test(Router): cover default callback resolution through Synapsis

Use the conventional `.gitkeep` filename so Git tooling recognizes
these placeholder files by default.

.gitignore

@@ -0,0 +1,4 @@
+/vendor/
+/.phpunit.cache/
+*.sqlite
+/.publish/

Makefile

@@ -0,0 +1,197 @@
+# DuckBrain development harness — Makefile
+#
+# This file (along with tests/, phpunit.xml, composer.*, .gitignore) lives
+# ONLY on the develop branch. master is a publish-only vitrine that contains
+# nothing but the readable artifact: nobody commits to master directly, and
+# no file outside the WHITELIST below ever reaches it.
+#
+# Daily loop:
+#   make test     run the unit suite (sqlite :memory:, no containers, no
+#                 network; installs dev dependencies first if missing)
+#   ...then develop on develop and commit there as usual.
+#
+# Multi-engine regression net (run it whenever Model/Database change):
+#   make integration            full matrix: brings the test services up,
+#                               runs the Integration suite on sqlite, mysql
+#                               and pgsql, then takes the services down even
+#                               if a leg fails or you interrupt it
+#   make integration-engine ENGINE=mysql
+#                               single leg (assumes services are already up);
+#                               the fastest inner loop while iterating
+#   make db-up / make db-down   manage the rootless podman test containers
+#                               (mariadb:11, postgres:16-alpine); idempotent
+#
+#   Hard port constraint: the services must bind default ports 3306/5432 on
+#   localhost because Database.php's DSN has no port field; stop any local
+#   server on those ports first (db-up aborts naming the port).
+#
+# Publishing ritual (human only — AI agents must never run it; it commits):
+#   1. make publish MSG="feat: ..."   (MSG optional, defaults to "sync: <date>")
+#   2. review the new master commit (git log -1 refs/heads/master); if the
+#      generated message needs polish, rewrite it BEFORE pushing, e.g.
+#      from Emacs
+#   3. git push origin master         (manual on purpose: pushing is a
+#                                      decision, never a side effect)
+#
+# How publish builds master — wipe-and-rebuild mirror, no merges, no
+# cherry-picks (see design decisions behind establish-dev-publish-workflow):
+#   - refuses to run off develop or with a dirty working tree
+#   - checks master out into a disposable worktree under .publish/
+#     (your current working tree is never touched)
+#   - for each WHITELIST path: removes master's copy and checks out develop's,
+#     so deleted/renamed artifact files never survive as ghosts in master
+#   - BLACKLIST then subtracts noise found INSIDE whitelisted paths
+#   - creates the commit only when the artifact actually changed; its body
+#     lists the develop commits (after the last-sync tag) that touched
+#     WHITELIST paths — pure-noise commits are filtered out automatically
+#   - moves the last-sync tag to develop's tip, removes the worktree, and
+#     prints any root entry left out of WHITELIST (add it if it belongs to
+#     the artifact)
+
+SHELL := /bin/bash
+
+.PHONY: test publish db-up db-up-mariadb db-up-postgres db-down integration integration-engine
+
+PHPUNIT := vendor/bin/phpunit
+
+# Engine for single-leg integration runs (services must already be up).
+ENGINE ?= sqlite
+
+# --- publish configuration -------------------------------------------------
+WHITELIST     := src config.php index.php autoload.php .htaccess readme.org
+BLACKLIST     :=
+DEVELOP_BRANCH  := develop
+DEVELOP_REF     := refs/heads/$(DEVELOP_BRANCH)
+MASTER_BRANCH   := master
+MASTER_REF      := refs/heads/$(MASTER_BRANCH)
+LAST_SYNC_TAG  := last-sync
+MSG            ?= sync: $(shell date +%Y-%m-%d)
+
+# --- integration database services (podman rootless) -----------------------
+# Default ports are non-negotiable: Database.php's DSN carries no port field,
+# so the engines must answer on 3306/5432. If a local server owns those
+# ports, stop it before `make db-up`.
+MARIADB_NAME    := duckbrain-test-mariadb
+POSTGRES_NAME   := duckbrain-test-postgres
+MARIADB_IMAGE   := docker.io/library/mariadb:11
+POSTGRES_IMAGE  := docker.io/library/postgres:16-alpine
+TEST_DB_NAME    := duckbrain_test
+TEST_DB_USER    := duckbrain
+TEST_DB_PASS    := duckbrain
+DB_READY_SECS   := 240
+
+test:
+	@test -x $(PHPUNIT) || composer install --no-interaction
+	./$(PHPUNIT) --testsuite Unit
+
+publish:
+	@if [ "$$(git branch --show-current)" != "$(DEVELOP_BRANCH)" ]; then \
+		echo "ABORT: publish must be invoked from $(DEVELOP_BRANCH) (current: '$$(git branch --show-current)')"; \
+		exit 1; \
+	fi
+	@if [ -n "$$(git status --porcelain)" ]; then \
+		echo "ABORT: working tree is dirty; commit your changes on $(DEVELOP_BRANCH) before publishing:"; \
+		git status --short; \
+		exit 1; \
+	fi
+	git worktree remove --force .publish/master 2>/dev/null || true
+	git worktree add --quiet .publish/master $(MASTER_BRANCH)
+	@test "$$(git -C .publish/master symbolic-ref HEAD)" = "$(MASTER_REF)" || { \
+		echo "ABORT: publish worktree HEAD is not attached to $(MASTER_REF)"; \
+		git worktree remove --force .publish/master; exit 1; }
+	@for w in $(WHITELIST); do git -C .publish/master rm -rf --ignore-unmatch --quiet -- $$w; done
+	git -C .publish/master checkout $(DEVELOP_REF) -- $(WHITELIST)
+	@for b in $(BLACKLIST); do git -C .publish/master rm -rf --ignore-unmatch --quiet -- $$b; done
+	git -C .publish/master diff --quiet $(DEVELOP_REF) -- $(WHITELIST)
+	@if git -C .publish/master diff --cached --quiet; then \
+		echo "nothing to publish: master already mirrors $(DEVELOP_BRANCH)"; \
+	else \
+		set -e; \
+		if git rev-parse -q --verify tags/$(LAST_SYNC_TAG) >/dev/null; then \
+			RANGE=$(LAST_SYNC_TAG)..$(DEVELOP_REF); \
+		else \
+			echo "note: no $(LAST_SYNC_TAG) tag yet; summarizing full $(DEVELOP_BRANCH) history"; \
+			RANGE=$(DEVELOP_REF); \
+		fi; \
+		BODY=$$(git log $$RANGE --oneline -- $(WHITELIST)); \
+		{ printf '%s\n' "$(MSG)"; printf '\n'; printf '%s\n' "$$BODY"; } > .publish/msg.txt; \
+		git -C .publish/master commit --quiet -F "$$(pwd)/.publish/msg.txt"; \
+		echo "publish commit created; review/edit it (before pushing) with your git tool of choice"; \
+	fi
+	git tag -f $(LAST_SYNC_TAG) $(DEVELOP_REF) >/dev/null
+	git worktree remove .publish/master
+	@echo "root entries left behind in $(DEVELOP_BRANCH) (add to WHITELIST if they belong to the artifact):"; \
+	comm -23 <(git ls-tree --name-only $(DEVELOP_REF) | sort) \
+	         <(for x in $(WHITELIST) $(BLACKLIST); do echo $$x; done | sort) | sed 's/^/  - /'
+
+db-up: db-up-mariadb db-up-postgres
+
+db-up-mariadb:
+	@if podman ps -a --format '{{.Names}}' | grep -qx $(MARIADB_NAME); then \
+		echo "reusing $(MARIADB_NAME)"; podman start $(MARIADB_NAME) >/dev/null; \
+	else \
+		(echo > /dev/tcp/127.0.0.1/3306) 2>/dev/null && { \
+			echo "ABORT: port 3306 already in use; stop the local MySQL/MariaDB server or free the port before db-up"; exit 1; } || true; \
+		podman run -d --name $(MARIADB_NAME) \
+			-e MARIADB_ROOT_PASSWORD=$(TEST_DB_PASS) \
+			-e MARIADB_DATABASE=$(TEST_DB_NAME) \
+			-e MARIADB_USER=$(TEST_DB_USER) \
+			-e MARIADB_PASSWORD=$(TEST_DB_PASS) \
+			-p 127.0.0.1:3306:3306 $(MARIADB_IMAGE) >/dev/null; \
+	fi
+	@echo "waiting for $(MARIADB_NAME) to accept connections..."; \
+	for i in $$(seq 1 $(DB_READY_SECS)); do \
+		podman exec $(MARIADB_NAME) mariadb-admin ping -h 127.0.0.1 -u $(TEST_DB_USER) -p$(TEST_DB_PASS) --silent >/dev/null 2>&1 \
+			&& echo "$(MARIADB_NAME) ready" && exit 0; \
+		sleep 2; \
+	done; \
+	echo "TIMEOUT: $(MARIADB_NAME) never became ready; inspect: podman logs $(MARIADB_NAME)"; exit 1
+
+db-up-postgres:
+	@if podman ps -a --format '{{.Names}}' | grep -qx $(POSTGRES_NAME); then \
+		echo "reusing $(POSTGRES_NAME)"; podman start $(POSTGRES_NAME) >/dev/null; \
+	else \
+		(echo > /dev/tcp/127.0.0.1/5432) 2>/dev/null && { \
+			echo "ABORT: port 5432 already in use; stop the local PostgreSQL server or free the port before db-up"; exit 1; } || true; \
+		podman run -d --name $(POSTGRES_NAME) \
+			-e POSTGRES_DB=$(TEST_DB_NAME) \
+			-e POSTGRES_USER=$(TEST_DB_USER) \
+			-e POSTGRES_PASSWORD=$(TEST_DB_PASS) \
+			-p 127.0.0.1:5432:5432 $(POSTGRES_IMAGE) >/dev/null; \
+	fi
+	@echo "waiting for $(POSTGRES_NAME) to accept connections..."; \
+	for i in $$(seq 1 $(DB_READY_SECS)); do \
+		podman exec $(POSTGRES_NAME) pg_isready -U $(TEST_DB_USER) -d $(TEST_DB_NAME) >/dev/null 2>&1 \
+			&& echo "$(POSTGRES_NAME) ready" && exit 0; \
+		sleep 2; \
+	done; \
+	echo "TIMEOUT: $(POSTGRES_NAME) never became ready; inspect: podman logs $(POSTGRES_NAME)"; exit 1
+
+db-down:
+	@for c in $(MARIADB_NAME) $(POSTGRES_NAME); do \
+		if podman ps -a --format '{{.Names}}' | grep -qx $$c; then \
+			podman stop $$c >/dev/null 2>&1; podman rm $$c >/dev/null 2>&1; echo "removed $$c"; \
+		else \
+			echo "$$c not present"; \
+		fi; \
+	done
+
+integration:
+	@bash -c ' \
+		trap "$(MAKE) db-down" EXIT; \
+		trap "exit 130" INT; \
+		trap "exit 143" TERM; \
+		$(MAKE) --no-print-directory db-up || exit 1; \
+		rc=0; \
+		for e in sqlite mysql pgsql; do \
+			echo "============ leg: $$e ============"; \
+			$(MAKE) --no-print-directory integration-engine ENGINE=$$e || rc=1; \
+		done; \
+		echo "=================================="; \
+		if [ $$rc -eq 0 ]; then echo "integration: all legs green"; else echo "integration: at least one leg FAILED (rc=1)"; fi; \
+		exit $$rc \
+	'
+
+integration-engine:
+	@test -x $(PHPUNIT) || composer install --no-interaction
+	DUCKBRAIN_TEST_DB=$(ENGINE) ./$(PHPUNIT) --testsuite Integration --cache-directory .phpunit.cache/$(ENGINE)

composer.json

@@ -0,0 +1,15 @@
+{
+    "name": "kj/duckbrain",
+    "description": "DuckBrain microframework - development harness (tests and tooling; never published to master).",
+    "type": "project",
+    "license": "MIT",
+    "require-dev": {
+        "fakerphp/faker": "^1.24",
+        "phpunit/phpunit": "^11.0"
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "Tests\\": "tests/"
+        }
+    }
+}

phpunit.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         bootstrap="tests/bootstrap.php"
+         colors="true"
+         cacheDirectory=".phpunit.cache"
+         executionOrder="depends,defects"
+         requireCoverageMetadata="false"
+         beStrictAboutOutputDuringTests="true"
+         failOnRisky="true"
+         failOnWarning="true">
+    <testsuites>
+        <testsuite name="Unit">
+            <directory>tests/Unit</directory>
+        </testsuite>
+        <testsuite name="Integration">
+            <directory>tests/Integration</directory>
+        </testsuite>
+    </testsuites>
+    <source>
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </source>
+</phpunit>

tests/Factories/Factory.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace Tests\Factories;
+
+use Faker\Factory as FakerFactory;
+use Faker\Generator;
+
+/**
+ * Factory - DuckBrain testing
+ *
+ * Clase base para crear fábricas de datos de prueba. Cada subclase
+ * define los atributos por defecto de un modelo y construye su
+ * instancia.
+ *
+ * @author KJ
+ * @website https://kj2.me
+ * @license MIT
+ */
+abstract class Factory
+{
+    protected static ?Generator $fake = null;
+
+    /**
+     * Devuelve una instancia de Faker (singleton por fábrica).
+     */
+    protected static function faker(): Generator
+    {
+        return static::$fake ??= FakerFactory::create();
+    }
+
+    /**
+     * Fusiona los atributos por defecto con los indicados.
+     *
+     * @param  array<string, mixed>  $attributes
+     * @return array<string, mixed>
+     */
+    protected static function attributes(array $attributes = []): array
+    {
+        return array_merge(static::definition(), $attributes);
+    }
+
+    /**
+     * Atributos por defecto de la fábrica.
+     *
+     * @return array<string, mixed>
+     */
+    abstract protected static function definition(): array;
+
+    /**
+     * Crea una instancia del modelo con los atributos dados.
+     *
+     * @param  array<string, mixed>  $attributes
+     */
+    abstract public static function create(array $attributes = []): object;
+}

tests/Integration/ModelCrudTest.php

@@ -0,0 +1,234 @@
+<?php
+
+namespace Tests\Integration;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use DateTime;
+use Libs\Database;
+use PDO;
+use ReflectionMethod;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelCrudTest - DuckBrain integration matrix
+ *
+ * Family: db, getInstance, getVars, className, table, add, save (new vs
+ * existing), update, delete, getById, getFirst, all, markAsSaved.
+ *
+ * Engine caveats respected here: all()/getFirst() carry no ORDER BY, so
+ * every assertion targets a specific id or a tally of rows created by this
+ * class. Rows accumulate across tests on persistent engines; nothing may
+ * assume an empty table.
+ */
+#[Group('integration')]
+final class ModelCrudTest extends TestCase
+{
+    /** @var list<int> Ids created by this test class (tally for counts). */
+    private static array $saved = [];
+
+    private static function schema(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+    }
+
+    private static function freshUser(): User
+    {
+        $n = count(self::$saved) + 1;
+
+        $user = new User();
+        $user->username  = 'user' . $n;
+        $user->email     = 'user' . $n . '@duckbrain.dev';
+        $user->bio       = 'bio ' . $n;
+        $user->age       = 20 + $n;
+        $user->isActive  = true;
+        $user->lastLogin = new DateTime('2026-09-05 10:00:00');
+        $user->save();
+
+        self::$saved[] = $user->id;
+
+        return $user;
+    }
+
+    private static function call(mixed $scope, string $method, array $args = []): mixed
+    {
+        return (new ReflectionMethod($scope, $method))->invokeArgs(is_object($scope) ? $scope : null, $args);
+    }
+
+    /** @return list<int> */
+    private static function idsOf(array $instances): array
+    {
+        $ids = array_map(static fn (User $u): int => (int) $u->id, $instances);
+        sort($ids);
+
+        return $ids;
+    }
+
+    #[Test]
+
+    public function classNameAndTableAreDerivedFromTheClass(): void
+    {
+        self::schema();
+
+        $this->assertSame('User', User::className());
+        $this->assertSame('users', self::call(User::class, 'table'));
+    }
+
+    #[Test]
+
+    public function dbIsTheSharedSingletonConnection(): void
+    {
+        self::schema();
+
+        $pdo = self::call(User::class, 'db');
+        $this->assertInstanceOf(PDO::class, $pdo);
+        $this->assertSame($pdo, self::call(User::class, 'db'));
+    }
+
+    #[Test]
+
+    public function saveInsertsThenUpdatesWithoutDuplicating(): void
+    {
+        self::schema();
+        $user = self::freshUser();
+
+        $this->assertGreaterThan(0, $user->id);
+        $this->assertCount(1, User::where('id', $user->id)->get());
+
+        $user->email = 'changed@duckbrain.dev';
+        $user->age   = 40;
+        $user->save();
+
+        $found = User::getById($user->id);
+        $this->assertSame('changed@duckbrain.dev', $found->email);
+        $this->assertSame(40, $found->age);
+        $this->assertCount(1, User::where('id', $user->id)->get(), 'second save() must UPDATE, not INSERT');
+    }
+
+    #[Test]
+
+    public function typedPropertiesSurviveTheRoundTrip(): void
+    {
+        self::schema();
+        $user = self::freshUser();
+        $user->email = null;
+        $user->save();
+
+        $found = User::getById($user->id);
+
+        $this->assertIsInt($found->id);
+        $this->assertNull($found->email, 'nullable typed property must hydrate back as null');
+        $this->assertIsInt($found->age);
+        $this->assertInstanceOf(DateTime::class, $found->lastLogin);
+        $this->assertTrue($found->isActive);
+    }
+
+    #[Test]
+
+    public function getByIdReturnsNullForMissingRows(): void
+    {
+        self::schema();
+
+        $this->assertNull(User::getById(99999));
+    }
+
+    #[Test]
+
+    public function getFirstRespectsTheWhereCondition(): void
+    {
+        self::schema();
+        $user = self::freshUser();
+
+        $found = User::where('id', $user->id)->getFirst();
+        $this->assertInstanceOf(User::class, $found);
+        $this->assertSame($user->id, $found->id);
+
+        $this->assertNull(User::where('id', 99999)->getFirst());
+    }
+
+    #[Test]
+
+    public function allReturnsEveryInstanceOfThisClass(): void
+    {
+        self::schema();
+        $a = self::freshUser();
+        $b = self::freshUser();
+
+        $all = self::idsOf(User::all());
+
+        $this->assertContains($a->id, $all);
+        $this->assertContains($b->id, $all);
+
+        // Defect-tolerant tally: rows deleted by other tests must not count.
+        $mine = [];
+        foreach (self::$saved as $id) {
+            if (User::getById($id) !== null) {
+                $mine[] = $id;
+            }
+        }
+        sort($mine);
+
+        $this->assertSame($mine, $all, 'all() must match exactly the live rows created by this class');
+    }
+
+    #[Test]
+
+    public function deleteRemovesTheRow(): void
+    {
+        self::schema();
+        $user = self::freshUser();
+
+        $user->delete();
+
+        $this->assertNull(User::getById($user->id));
+        $this->assertNotContains($user->id, self::idsOf(User::all()));
+    }
+
+    #[Test]
+
+    public function markAsSavedTurnsTheNextSaveIntoAnUpdate(): void
+    {
+        self::schema();
+        self::freshUser();
+        $before = count(User::all());
+
+        $ghost = new User();
+        $ghost->id       = 900;
+        $ghost->username = 'ghost';
+        $ghost->markAsSaved();
+        $ghost->save();
+
+        $this->assertNull(User::getById(900), 'markAsSaved() must prevent INSERT even with a manual id');
+        $this->assertCount($before, User::all());
+    }
+
+    #[Test]
+
+    public function getVarsExposesSnakeCasedCastColumns(): void
+    {
+        self::schema();
+        $user = self::freshUser();
+
+        $vars = self::call($user, 'getVars');
+
+        $this->assertSame(
+            ['age', 'bio', 'email', 'id', 'is_active', 'last_login', 'username'],
+            (static function (array $keys): array {
+                sort($keys);
+
+                return $keys;
+            })(array_keys($vars))
+        );
+        $this->assertSame('2026-09-05 10:00:00', $vars['last_login']);
+        $this->assertIsBool($vars['is_active']);
+    }
+}

tests/Integration/ModelFailureTest.php

@@ -0,0 +1,100 @@
+<?php
+
+namespace Tests\Integration;
+
+use Exception;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use ReflectionMethod;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelFailureTest - DuckBrain integration matrix
+ *
+ * Family: query-failure state handling (findings F2 / spec model).
+ *
+ * All contamination is provoked and observed INSIDE a single test: the
+ * harness-wide resetQuery guard in Tests\TestCase::setUp() protects the
+ * next test, never the current one, so these assertions depend solely on
+ * Model::query()'s own bookkeeping.
+ */
+#[Group('integration')]
+final class ModelFailureTest extends TestCase
+{
+    /** @var list<int> */
+    private static array $ids = [];
+
+    private const BAD_SQL = 'SELECT * FROM table_that_does_not_exist';
+
+    public static function setUpBeforeClass(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+
+        foreach (['fer', 'fiona', 'frog'] as $name) {
+            $user = new User();
+            $user->username = $name;
+            $user->email    = $name . '@duckbrain.dev';
+            $user->age      = 33;
+            $user->save();
+            self::$ids[] = (int) $user->id;
+        }
+    }
+
+    private static function runQuery(string $sql, bool $resetQuery = true): void
+    {
+        (new ReflectionMethod(User::class, 'query'))->invokeArgs(null, [$sql, $resetQuery]);
+    }
+
+    private static function currentSql(): string
+    {
+        return (new ReflectionMethod(User::class, 'buildQuery'))->invoke(null);
+    }
+
+    #[Test]
+    public function failingQueryDoesNotContaminateTheNextQuery(): void
+    {
+        User::where('id', self::$ids[0]);
+
+        try {
+            self::runQuery(self::BAD_SQL);
+            $this->fail('a query against a missing table must throw');
+        } catch (Exception $e) {
+            $this->assertStringContainsString('Error at query to database', $e->getMessage());
+        }
+
+        // With the default resetQuery: true, the failed run must have left
+        // the builder as good as new; get() therefore sees all three rows.
+        $this->assertCount(3, User::get(), 'builder state leaked from the failed query');
+    }
+
+    #[Test]
+    public function failedKeepStateQueryLeavesTheWhereForRetry(): void
+    {
+        User::where('username', 'fiona');
+
+        try {
+            self::runQuery(self::BAD_SQL, false);
+            $this->fail('a query against a missing table must throw');
+        } catch (Exception $e) {
+            $this->assertStringContainsString('Error at query to database', $e->getMessage());
+        }
+
+        // resetQuery: false contracts to keep the where alive for the
+        // caller's deliberate retry (also guards against a fix that resets
+        // unconditionally).
+        $this->assertStringContainsString('WHERE', self::currentSql());
+
+        $retry = User::get();
+        $this->assertCount(1, $retry, 'retry after failure must reuse the kept where');
+        $this->assertSame('fiona', $retry[0]->username);
+    }
+}

tests/Integration/ModelFilterTest.php

@@ -0,0 +1,245 @@
+<?php
+
+namespace Tests\Integration;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use Libs\Model;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelFilterTest - DuckBrain integration matrix
+ *
+ * Family: select, from, where, and, or, whereIn, whereNotIn, whereNull,
+ * whereNotNull, whereExists, whereNotExists, limit, orderBy, count, plus
+ * resetQuery/buildQuery observed through behavior (state must not leak
+ * between executed queries).
+ */
+#[Group('integration')]
+final class ModelFilterTest extends TestCase
+{
+    /** @var list<int> ids of alice, bob, carol, dave */
+    private static array $ids = [];
+
+    public static function setUpBeforeClass(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+        self::createTable('posts', [
+            'id'      => 'pk',
+            'user_id' => 'number',
+            'title'   => 'string',
+            'content' => 'text',
+            'rating'  => 'number',
+        ]);
+
+        $rows = [
+            ['alice', 'alice@duckbrain.dev', 'first', 20, true],
+            ['bob', 'bob@duckbrain.dev', 'second', 30, true],
+            ['carol', null, 'third', 40, false],
+            ['dave', 'dave@duckbrain.dev', null, 50, true],
+        ];
+
+        foreach ($rows as [$username, $email, $bio, $age, $active]) {
+            $user = new User();
+            $user->username = $username;
+            $user->email    = $email;
+            $user->bio      = $bio;
+            $user->age      = $age;
+            $user->isActive = $active;
+            $user->save();
+            self::$ids[] = (int) $user->id;
+        }
+
+        // A post owned by alice only, for the EXISTS tests.
+        $post = new \Tests\Models\Post();
+        $post->userId  = self::$ids[0];
+        $post->title   = 'hello world';
+        $post->content = 'body';
+        $post->rating  = 4.5;
+        $post->save();
+    }
+
+    /** @return list<int> */
+    private static function sortedIds(array $instances): array
+    {
+        $ids = array_map(static fn (Model $m): int => (int) $m->id, $instances);
+        sort($ids);
+
+        return $ids;
+    }
+
+    #[Test]
+
+    public function whereEqualityAndOperatorForms(): void
+    {
+        $this->assertSame(
+            [self::$ids[1]],
+            self::sortedIds(User::where('username', 'bob')->get())
+        );
+        $this->assertSame(
+            [self::$ids[2], self::$ids[3]],
+            self::sortedIds(User::where('age', '>', '35')->get())
+        );
+    }
+
+    #[Test]
+
+    public function andNestsConditions(): void
+    {
+        $this->assertSame(
+            [self::$ids[3]],
+            self::sortedIds(User::where('age', '>', '25')->and('username', 'dave')->get())
+        );
+    }
+
+    #[Test]
+
+    public function orCombinesAlternativeConditions(): void
+    {
+        $this->assertSame(
+            [self::$ids[0], self::$ids[3]],
+            self::sortedIds(User::where('username', 'alice')->or('username', 'dave')->get())
+        );
+    }
+
+    #[Test]
+
+    public function whereInAndWhereNotIn(): void
+    {
+        $in = self::sortedIds(User::whereIn('username', ['alice', 'carol'])->get());
+        $this->assertSame([self::$ids[0], self::$ids[2]], $in);
+
+        $notIn = self::sortedIds(User::whereNotIn('username', ['alice', 'carol'])->get());
+        $this->assertSame([self::$ids[1], self::$ids[3]], $notIn);
+    }
+
+    #[Test]
+
+    public function whereNullAndWhereNotNull(): void
+    {
+        $this->assertSame(
+            [self::$ids[3]],
+            self::sortedIds(User::whereNull('bio')->get())
+        );
+        $this->assertSame(
+            [self::$ids[2]],
+            self::sortedIds(User::whereNull('email')->get())
+        );
+        $this->assertCount(3, User::whereNotNull('email')->get());
+    }
+
+    #[Test]
+
+    public function whereExistsAndWhereNotExists(): void
+    {
+        $correlated = 'SELECT 1 FROM posts WHERE posts.user_id = users.id';
+
+        $this->assertSame(
+            [self::$ids[0]],
+            self::sortedIds(User::whereExists($correlated)->get())
+        );
+        $this->assertSame(
+            [self::$ids[1], self::$ids[2], self::$ids[3]],
+            self::sortedIds(User::whereNotExists($correlated)->get())
+        );
+    }
+
+    #[Test]
+
+    public function selectAndFromRestrictTheProjection(): void
+    {
+        $rows = User::select('username')->from('users')->where('username', 'bob')->get();
+
+        $this->assertCount(1, $rows);
+        $this->assertSame('bob', $rows[0]->username);
+    }
+
+    #[Test]
+
+    public function limitSingleAndOffsetForms(): void
+    {
+        $firstTwo = User::orderBy('id', 'ASC')->limit(2)->get();
+        $this->assertSame(
+            [self::$ids[0], self::$ids[1]],
+            array_map(static fn (Model $m): int => (int) $m->id, $firstTwo)
+        );
+
+        // limit(offset, quantity) -> skip the first two.
+        $lastTwo = User::orderBy('id', 'ASC')->limit(2, 2)->get();
+        $this->assertSame(
+            [self::$ids[2], self::$ids[3]],
+            array_map(static fn (Model $m): int => (int) $m->id, $lastTwo)
+        );
+    }
+
+    #[Test]
+
+    public function orderByColumnAscendingAndDescending(): void
+    {
+        $asc = array_map(static fn (Model $m): string => (string) $m->age, User::orderBy('age', 'ASC')->get());
+        $this->assertSame(['20', '30', '40', '50'], array_map('strval', array_map('intval', $asc)));
+
+        $descFirst = User::orderBy('age', 'DESC')->getFirst();
+        $this->assertSame('dave', $descFirst->username);
+    }
+
+    #[Test]
+
+    public function countWithAndWithoutConditions(): void
+    {
+        $this->assertSame(4, User::count());
+        $this->assertSame(3, User::where('age', '>', '25')->count());
+    }
+
+    #[Test]
+
+    public function countWithUseLimit(): void
+    {
+        $this->assertSame(2, User::orderBy('id', 'ASC')->limit(2)->count(true, true));
+    }
+
+    #[Test]
+
+    public function countWithoutResetKeepsTheOriginalQuery(): void
+    {
+        User::where('age', '>', '25');
+        $count = User::count(false);
+
+        $this->assertSame(3, $count);
+        $this->assertSame(
+            [self::$ids[1], self::$ids[2], self::$ids[3]],
+            self::sortedIds(User::get()),
+            'count(false) must leave the where active; get() consumes it'
+        );
+    }
+
+    #[Test]
+
+    public function queryStateResetsAfterExecution(): void
+    {
+        $one = User::where('id', self::$ids[0])->getFirst();
+        $this->assertSame('alice', $one->username);
+
+        $this->assertCount(4, User::all(), 'where must not leak into the next query');
+        $this->assertCount(4, User::get());
+    }
+
+    #[Test]
+
+    public function orderByRandReturnsEveryRow(): void
+    {
+        // The readme matrix promises orderBy ok on the three engines.
+        // Model emits literal RAND(); sqlite and PostgreSQL know RANDOM().
+        // This test documents the promise; failures are findings, not noise.
+        $this->assertCount(4, User::orderBy('RAND')->get());
+    }
+}

tests/Integration/ModelJoinTest.php

@@ -0,0 +1,145 @@
+<?php
+
+namespace Tests\Integration;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\Models\Post;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelJoinTest - DuckBrain integration matrix
+ *
+ * Family: innerJoin, leftJoin, rightJoin, crossJoin, groupBy.
+ *
+ * Data has orphans on both sides (carol/dave have no posts; no post lacks an
+ * owner) so join cardinality actually discriminates. Projections are always
+ * qualified and limited to driver-model columns: a bare SELECT * on
+ * rightJoin differs between engines BY DESIGN (the sqlite branch rewrites
+ * into a swapped LEFT JOIN, see readme "fixed"); asserting on ambiguous
+ * duplicate columns would test that rewrite detail, not the join promise.
+ */
+#[Group('integration')]
+final class ModelJoinTest extends TestCase
+{
+    /** @var array<string,int> username => id */
+    private static array $ids = [];
+
+    public static function setUpBeforeClass(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+        self::createTable('posts', [
+            'id'      => 'pk',
+            'user_id' => 'number',
+            'title'   => 'string',
+            'content' => 'text',
+            'rating'  => 'number',
+        ]);
+
+        foreach ([['alice', true], ['bob', true], ['carol', false], ['dave', true]] as $row) {
+            $user = new User();
+            $user->username = $row[0];
+            $user->email    = $row[0] . '@duckbrain.dev';
+            $user->age      = 30;
+            $user->isActive = $row[1];
+            $user->save();
+            self::$ids[$row[0]] = (int) $user->id;
+        }
+
+        foreach ([['p1', 'alice'], ['p2', 'alice'], ['p3', 'bob']] as [$title, $owner]) {
+            $post = new Post();
+            $post->title  = $title;
+            $post->userId = self::$ids[$owner];
+            $post->save();
+        }
+    }
+
+    /** @return list<string> sorted usernames of the result rows */
+    private static function names(array $rows): array
+    {
+        $names = array_map(static fn (User $u): string => (string) $u->username, $rows);
+        sort($names);
+
+        return $names;
+    }
+
+    #[Test]
+    public function leftJoinKeepsUsersWithoutPosts(): void
+    {
+        $rows = User::select('users.id', 'users.username')
+            ->leftJoin('posts', 'users.id', '=', 'posts.user_id')
+            ->get();
+
+        $this->assertSame(
+            ['alice', 'alice', 'bob', 'carol', 'dave'],
+            self::names($rows),
+            'LEFT JOIN must keep orphan users exactly once each'
+        );
+    }
+
+    #[Test]
+    public function innerJoinDropsBothOrphans(): void
+    {
+        $rows = User::select('users.id', 'users.username')
+            ->innerJoin('posts', 'users.id', '=', 'posts.user_id')
+            ->get();
+
+        $this->assertSame(['alice', 'alice', 'bob'], self::names($rows));
+    }
+
+    #[Test]
+    public function rightJoinKeepsEveryRowOfTheJoinedTable(): void
+    {
+        // sqlite takes the swapped-LEFT-JOIN rewrite; mysql/pgsql take the
+        // native RIGHT JOIN branch. Both must produce the same observable set.
+        $rows = User::select('users.id', 'users.username')
+            ->rightJoin('posts', 'users.id', '=', 'posts.user_id')
+            ->get();
+
+        $names = self::names($rows);
+        $this->assertCount(3, $rows, 'posts are the preserved side: 3 rows');
+        $this->assertSame(['alice', 'alice', 'bob'], $names);
+        $this->assertNotContains('carol', $names, 'users without posts vanish from a RIGHT JOIN over posts');
+    }
+
+    #[Test]
+    public function crossJoinProducesTheCartesianProduct(): void
+    {
+        $rows = User::select('users.id', 'posts.id')
+            ->crossJoin('posts')
+            ->get();
+
+        $this->assertCount(12, $rows, '4 users x 3 posts');
+
+        // Qualified both-id columns: the last one wins on every engine
+        // (users.* comes first), so the surviving id set is 1..3.
+        $surviving = array_unique(array_map(static fn (User $u): int => (int) $u->id, $rows));
+        sort($surviving);
+        $this->assertSame([1, 2, 3], $surviving);
+    }
+
+    #[Test]
+    public function groupByCollapsesRowsPerGroup(): void
+    {
+        $statuses = User::select('users.is_active')->groupBy('users.is_active')->get();
+        $this->assertCount(2, $statuses, 'active and inactive groups');
+
+        $owners = User::select('users.id', 'users.username')
+            ->innerJoin('posts', 'users.id', '=', 'posts.user_id')
+            ->groupBy('users.id')
+            ->get();
+        $names = self::names($owners);
+        sort($names);
+
+        $this->assertSame(['alice', 'bob'], $names, 'one row per user that owns posts');
+    }
+}

tests/Integration/ModelSearchTest.php

@@ -0,0 +1,130 @@
+<?php
+
+namespace Tests\Integration;
+
+use DateTime;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelSearchTest - DuckBrain integration matrix
+ *
+ * Family: search (mysql CONCAT branch vs sqlite/pgsql CAST||LIKE branch),
+ * plus filters that bind every supported column type and must agree on
+ * matches across engines. Search terms are chosen case-insensitively stable
+ * (MySQL LIKE is case-insensitive by collation, PostgreSQL's is not).
+ */
+#[Group('integration')]
+final class ModelSearchTest extends TestCase
+{
+    /** @var array<string,int> */
+    private static array $ids = [];
+
+    public static function setUpBeforeClass(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+
+        $seed = [
+            ['alice', 'alice@duckbrain.dev', 'alpha keeper',   20, true],
+            ['bob',   'bob@duckbrain.dev',   'beta reader',    30, true],
+            ['carol', 'carol@duckbrain.dev', 'gamma dreamer',  40, false],
+            ['dave',  'dave@duckbrain.dev',  'delta builder',  50, true],
+        ];
+
+        foreach ($seed as [$username, $email, $bio, $age, $active]) {
+            $user = new User();
+            $user->username  = $username;
+            $user->email     = $email;
+            $user->bio       = $bio;
+            $user->age       = $age;
+            $user->isActive  = $active;
+            $user->lastLogin = new DateTime('2026-09-05 10:00:00');
+            $user->save();
+            self::$ids[$username] = (int) $user->id;
+        }
+    }
+
+    /** @return list<int> */
+    private static function idsOf(array $rows): array
+    {
+        $ids = array_map(static fn (User $u): int => (int) $u->id, $rows);
+        sort($ids);
+
+        return $ids;
+    }
+
+    #[Test]
+    public function searchMatchesAcrossAllDefaultColumns(): void
+    {
+        // 'ali' occurs only in alice's username/bio space.
+        $this->assertSame(
+            [self::$ids['alice']],
+            self::idsOf(User::search('ali')->get())
+        );
+    }
+
+    #[Test]
+    public function searchFindsNumericValueThroughTextCasting(): void
+    {
+        // The number column must be matched by its textual form: sqlite
+        // casts REAL to '30.0' while mysql/pgsql yield '30'; both contain 30.
+        $this->assertSame(
+            [self::$ids['bob']],
+            self::idsOf(User::search('30')->get())
+        );
+    }
+
+    #[Test]
+    public function searchHonorsExplicitColumnList(): void
+    {
+        $this->assertSame(
+            [self::$ids['alice']],
+            self::idsOf(User::search('lpha', ['bio'])->get())
+        );
+        $this->assertSame(
+            [self::$ids['carol']],
+            self::idsOf(User::search('arol', ['username', 'email'])->get())
+        );
+    }
+
+    #[Test]
+    public function searchCombinesWithWhere(): void
+    {
+        $this->assertSame(
+            [self::$ids['alice']],
+            self::idsOf(User::where('is_active', '1')->search('li')->get())
+        );
+    }
+
+    #[Test]
+    public function everyColumnTypeFiltersConsistently(): void
+    {
+        $this->assertSame([self::$ids['alice']], self::idsOf(User::where('id', self::$ids['alice'])->get()));
+        $this->assertSame([self::$ids['bob']], self::idsOf(User::where('email', 'bob@duckbrain.dev')->get()));
+        $this->assertSame([self::$ids['carol']], self::idsOf(User::where('is_active', '0')->get()));
+        $this->assertCount(4, User::where('last_login', '>', '2026-09-05 09:00:00')->get());
+        $this->assertSame([self::$ids['dave']], self::idsOf(User::where('age', '>=', '50')->get()));
+    }
+
+    #[Test]
+    public function booleanFalseSurvivesTheRoundTrip(): void
+    {
+        // Promise of the matrix: typed properties hydrate faithfully on the
+        // three engines. PostgreSQL reports boolean false as 'f' and the
+        // core casts nothing -> this is the R2 probe.
+        $carol = User::getById(self::$ids['carol']);
+
+        $this->assertNotNull($carol);
+        $this->assertFalse($carol->isActive, 'inactive user must hydrate as bool false');
+    }
+}

tests/Integration/ModelTransactionTest.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace Tests\Integration;
+
+use Exception;
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use ReflectionMethod;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * ModelTransactionTest - DuckBrain integration matrix
+ *
+ * Family: beginTransaction, commit, rollBack, plus the implicit rollBack
+ * that Model.php performs when a query fails mid-transaction (and the
+ * Exception it rethrows wrapping the PDO error).
+ */
+#[Group('integration')]
+final class ModelTransactionTest extends TestCase
+{
+    public static function setUpBeforeClass(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+    }
+
+    private static function seed(string $username): User
+    {
+        $user = new User();
+        $user->username = $username;
+        $user->email    = $username . '@duckbrain.dev';
+        $user->age      = 25;
+        $user->save();
+
+        return $user;
+    }
+
+    #[Test]
+    public function commitMakesPendingWritesVisible(): void
+    {
+        User::beginTransaction();
+        $user = self::seed('committed_alice');
+        $this->assertTrue(User::commit());
+
+        $this->assertNotNull(User::getById($user->id));
+    }
+
+    #[Test]
+    public function rollBackDiscardsPendingWrites(): void
+    {
+        User::beginTransaction();
+        $user = self::seed('rolled_bob');
+        $this->assertTrue(User::rollBack());
+
+        $this->assertNull(User::getById($user->id));
+    }
+
+    #[Test]
+    public function aFailingQueryRollsBackTheOpenTransaction(): void
+    {
+        User::beginTransaction();
+        $user = self::seed('wrecked_carol');
+
+        // Dirty the builder BEFORE failing: only a leftover-free result after
+        // the exception proves query() itself cleaned up (finding F2).
+        User::where('age', '>', '30');
+
+        try {
+            (new ReflectionMethod(User::class, 'query'))
+                ->invokeArgs(null, ['SELECT * FROM table_that_does_not_exist']);
+            $this->fail('a failing query inside a transaction must throw');
+        } catch (Exception $e) {
+            $this->assertStringContainsString('Error at query to database', $e->getMessage());
+        }
+
+        $this->assertFalse(self::db()->inTransaction(), 'the exception path must close the transaction');
+
+        $sqlAfterFailure = (new ReflectionMethod(User::class, 'buildQuery'))->invoke(null);
+        $this->assertSame(
+            'SELECT * FROM users',
+            $sqlAfterFailure,
+            'a failed query must leave the builder at its default state'
+        );
+
+        $this->assertNull(User::where('username', 'wrecked_carol')->getFirst(), 'pending insert must be undone');
+    }
+}

tests/Integration/SchemaSmokeTest.php

@@ -0,0 +1,91 @@
+<?php
+
+namespace Tests\Integration;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\Attributes\Test;
+use DateTime;
+use InvalidArgumentException;
+use Tests\Models\User;
+use Tests\TestCase;
+
+/**
+ * SchemaSmokeTest - DuckBrain test harness
+ *
+ * Integration smoke test: the six logical column types must translate into
+ * valid DDL for the current engine and round-trip a row. Runs on all three
+ * legs (sqlite, mysql, pgsql) unchanged.
+ */
+#[Group('integration')]
+final class SchemaSmokeTest extends TestCase
+{
+    #[Test]
+    public function allLogicalTypesCreateAndRoundTrip(): void
+    {
+        self::createTable('smoke_types', [
+            'id'         => 'pk',
+            'label'      => 'string',
+            'body'       => 'text',
+            'amount'     => 'number',
+            'active'     => 'bool',
+            'created_at' => 'timestamp',
+        ]);
+
+        $insert = self::db()->prepare(
+            'INSERT INTO smoke_types (label, body, amount, active, created_at) VALUES (?, ?, ?, ?, ?)'
+        );
+        $insert->execute(['widget', 'a longer free-form body', 12.5, true, '2026-09-05 12:34:56']);
+
+        $row = self::db()->query('SELECT * FROM smoke_types')->fetch();
+
+        $this->assertSame(1, (int) $row['id']);
+        $this->assertSame('widget', $row['label']);
+        $this->assertSame('a longer free-form body', $row['body']);
+        $this->assertEquals(12.5, (float) $row['amount']);
+        $this->assertTrue(filter_var($row['active'], FILTER_VALIDATE_BOOLEAN));
+        $this->assertStringStartsWith('2026-09-05 12:34:56', (string) $row['created_at']);
+    }
+
+    #[Test]
+
+    public function saveAssignsPrimaryKeyAndGetByIdRoundTrips(): void
+    {
+        self::createTable('users', [
+            'id'         => 'pk',
+            'username'   => 'string',
+            'email'      => 'string',
+            'bio'        => 'text',
+            'age'        => 'number',
+            'is_active'  => 'bool',
+            'last_login' => 'timestamp',
+        ]);
+
+        $user = new User();
+        $user->username  = 'keyjay';
+        $user->email     = 'kj@duckbrain.dev';
+        $user->bio       = 'framework keeper';
+        $user->age       = 29;
+        $user->isActive  = true;
+        $user->lastLogin = new DateTime('2026-09-05 10:00:00');
+        $user->save();
+
+        $this->assertSame(1, $user->id, 'save() should assign the generated primary key');
+
+        $found = User::getById(1);
+        $this->assertNotNull($found);
+        $this->assertSame('keyjay', $found->username);
+        $this->assertSame(29, $found->age);
+        $this->assertTrue($found->isActive);
+        $this->assertInstanceOf(DateTime::class, $found->lastLogin);
+        $this->assertSame('2026-09-05 10:00:00', $found->lastLogin->format('Y-m-d H:i:s'));
+    }
+
+    #[Test]
+
+    public function unknownLogicalTypeFails(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+
+        self::createTable('smoke_bad', ['x' => 'money']);
+    }
+}

tests/Models/Post.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Tests\Models;
+
+use Libs\Model;
+
+/**
+ * Post - DuckBrain test fixture
+ *
+ * Second table of the integration matrix, joined to Users through user_id.
+ * Column names avoid SQL reserved words on every engine.
+ */
+final class Post extends Model
+{
+    public ?int $id;
+    public ?int $userId;
+    public string $title;
+    public ?string $content;
+    public ?float $rating;
+}

tests/Models/User.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Tests\Models;
+
+use DateTime;
+use Libs\Model;
+
+/**
+ * User - DuckBrain test fixture
+ *
+ * Public model used by the integration matrix. $id is declared WITHOUT a
+ * default so it stays uninitialized until the database assigns it:
+ * Model::getVars() skips uninitialized typed properties, which lets
+ * AUTOINCREMENT / AUTO_INCREMENT / SERIAL generate the primary key and
+ * Model::add() assign it back to the instance.
+ */
+final class User extends Model
+{
+    public ?int $id;
+    public string $username;
+    public ?string $email;
+    public ?string $bio;
+    public ?int $age;
+    public bool $isActive = false;
+    public ?DateTime $lastLogin;
+}

tests/TestCase.php

@@ -0,0 +1,136 @@
+<?php
+
+namespace Tests;
+
+use Libs\Database;
+use Libs\Model;
+use PDO;
+use PHPUnit\Framework\TestCase as FrameworkTestCase;
+
+/**
+ * TestCase - DuckBrain test harness
+ *
+ * Base class for the framework's own tests. Deliberately lightweight: this
+ * repo has no migrations/ nor duckbrain-commands, so each test defines its
+ * schema with raw DDL through createTable(), and tables registered there are
+ * dropped automatically after the class finishes.
+ */
+abstract class TestCase extends FrameworkTestCase
+{
+    /**
+     * @var list<string> Tables created through createTable() for this class.
+     */
+    private static array $tables = [];
+
+    /**
+     * Clears Model's static query-builder state before every test.
+     *
+     * A query that dies mid-flight (unsupported function, constraint
+     * violation, ...) never reaches Model's internal resetQuery(), so
+     * leftovers would leak into the next test otherwise. This keeps the
+     * suite order-independent regardless of PHPUnit's executionOrder.
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        (new \ReflectionMethod(Model::class, 'resetQuery'))->invoke(null);
+    }
+
+    /**
+     * Returns the PDO connection to the in-memory test database.
+     *
+     * @return PDO
+     */
+    protected static function db(): PDO
+    {
+        return Database::getInstance(DB_TYPE, DB_HOST, DB_NAME, DB_USER, DB_PASS);
+    }
+
+    /**
+     * DDL fragments per engine for each logical column type.
+     *
+     * @var array<string,array<string,string>>
+     */
+    private const TYPE_DDL = [
+        'sqlite' => [
+            'pk'        => 'INTEGER PRIMARY KEY AUTOINCREMENT',
+            'string'    => 'VARCHAR(255)',
+            'text'      => 'TEXT',
+            'number'    => 'REAL',
+            'bool'      => 'INTEGER',
+            'timestamp' => 'TEXT',
+        ],
+        'mysql' => [
+            'pk'        => 'INT AUTO_INCREMENT PRIMARY KEY',
+            'string'    => 'VARCHAR(255)',
+            'text'      => 'TEXT',
+            'number'    => 'DOUBLE',
+            'bool'      => 'TINYINT(1)',
+            'timestamp' => 'DATETIME',
+        ],
+        'pgsql' => [
+            'pk'        => 'SERIAL PRIMARY KEY',
+            'string'    => 'VARCHAR(255)',
+            'text'      => 'TEXT',
+            'number'    => 'DOUBLE PRECISION',
+            'bool'      => 'BOOLEAN',
+            'timestamp' => 'TIMESTAMP',
+        ],
+    ];
+
+    /**
+     * Creates a table in the test database from logical column types and
+     * registers it for cleanup. The DDL is translated per engine, so the
+     * same declaration works on sqlite, MySQL/MariaDB and PostgreSQL.
+     *
+     * @param string $name
+     *                     Table name (avoid SQL reserved words).
+     *
+     * @param array<string,string> $columns
+     *                                       Map of column name to logical type:
+     *                                       pk|string|text|number|bool|timestamp.
+     */
+    protected static function createTable(string $name, array $columns): void
+    {
+        $types = self::TYPE_DDL[DB_TYPE] ?? throw new \InvalidArgumentException(
+            'No type translation for DB_TYPE ' . DB_TYPE
+        );
+
+        $ddl = [];
+        foreach ($columns as $column => $type) {
+            $fragment = $types[$type] ?? throw new \InvalidArgumentException(
+                "Unknown logical type '{$type}' for column '{$column}'; "
+                . 'expected: ' . implode(', ', array_keys($types))
+            );
+            $ddl[] = $column . ' ' . $fragment;
+        }
+
+        static::db()->exec("CREATE TABLE IF NOT EXISTS {$name} (" . implode(', ', $ddl) . ')');
+        static::$tables[] = $name;
+    }
+
+    /**
+     * Never let an aborted test leak an open transaction into the next one.
+     */
+    protected function tearDown(): void
+    {
+        if (static::db()->inTransaction()) {
+            static::db()->rollBack();
+        }
+
+        parent::tearDown();
+    }
+
+    /**
+     * Drops every table registered through createTable() during this class.
+     */
+    public static function tearDownAfterClass(): void
+    {
+        foreach (array_unique(static::$tables) as $table) {
+            static::db()->exec("DROP TABLE IF EXISTS {$table}");
+        }
+
+        static::$tables = [];
+    }
+}

tests/Unit/BootstrapTest.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\Attributes\Test;
+use Libs\Neuron;
+use PDO;
+use Tests\TestCase;
+
+/**
+ * BootstrapTest - DuckBrain test harness
+ *
+ * Prueba de humo de la infraestructura: autoload de composer + framework,
+ * constantes de la DB de prueba y conexión PDO realmente utilizable. Si
+ * algo del entorno está mal, esta prueba falla primero con el diagnóstico.
+ */
+final class BootstrapTest extends TestCase
+{
+    #[Test]
+    public function frameworkClassesAreAutoloaded(): void
+    {
+        $this->assertTrue(
+            class_exists(Neuron::class),
+            'MISSING AUTOLOAD: autoload.php did not resolve Libs\Neuron; check ROOT_CORE and run from the project root'
+        );
+
+        $neuron = new Neuron(['key' => 'value']);
+        $this->assertSame('value', $neuron->key);
+        $this->assertNull($neuron->doesNotExist);
+    }
+
+    #[Test]
+
+    public function databaseConstantsPointToInMemorySqlite(): void
+    {
+        $this->assertSame(
+            'sqlite',
+            DB_TYPE,
+            'MISSING OVERRIDE: DB_TYPE comes from config.php; the bootstrap must define the DB_* constants BEFORE requiring autoload.php'
+        );
+        $this->assertSame(':memory:', DB_NAME, 'DB_NAME should be :memory: so tests never touch disks or servers');
+    }
+
+    #[Test]
+
+    public function testDatabaseIsUsable(): void
+    {
+        $db = self::db();
+        $this->assertInstanceOf(PDO::class, $db, 'Could not obtain the test PDO connection');
+        $this->assertSame($db, self::db(), 'Database::getInstance should return the same singleton');
+
+        $db->exec('CREATE TABLE smoke (id INTEGER PRIMARY KEY, v TEXT)');
+        $db->prepare('INSERT INTO smoke (v) VALUES (?)')->execute(['quack']);
+        $this->assertSame('quack', $db->query('SELECT v FROM smoke')->fetchColumn());
+        $db->exec('DROP TABLE smoke');
+    }
+}

tests/Unit/NeuronTest.php

@@ -0,0 +1,69 @@
+<?php
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\Attributes\Test;
+use Libs\Neuron;
+use Tests\TestCase;
+
+/**
+ * NeuronTest - DuckBrain test harness
+ *
+ * Regression net para el contenedor de valores del core: construcción
+ * desde array/objeto, propiedades dinámicas y null en inexistentes.
+ */
+final class NeuronTest extends TestCase
+{
+    #[Test]
+    public function constructFromAssociativeArray(): void
+    {
+        $n = new Neuron(['username' => 'kj', 'level' => 3]);
+
+        $this->assertSame('kj', $n->username);
+        $this->assertSame(3, $n->level);
+    }
+
+    #[Test]
+
+    public function constructFromObjectCopiesPublicProperties(): void
+    {
+        $source = new \stdClass();
+        $source->id = 7;
+        $source->email = 'kj@example.com';
+
+        $n = new Neuron($source);
+
+        $this->assertSame(7, $n->id);
+        $this->assertSame('kj@example.com', $n->email);
+    }
+
+    #[Test]
+
+    public function undefinedPropertyIsNullWithoutNotice(): void
+    {
+        $n = new Neuron();
+
+        $this->assertNull($n->thisDoesNotExist);
+    }
+
+    #[Test]
+
+    public function dynamicPropertiesCanBeAssignedAndRead(): void
+    {
+        $n = new Neuron();
+        $n->fresh = ['a', 'b'];
+
+        $this->assertSame(['a', 'b'], $n->fresh);
+    }
+
+    #[Test]
+
+    public function nestedValuesArePreservedVerbatim(): void
+    {
+        $payload = ['meta' => ['tags' => ['x', 'y'], 'n' => null]];
+        $n = new Neuron($payload);
+
+        $this->assertSame($payload['meta'], $n->meta);
+        $this->assertNull($n->meta['n']);
+    }
+}

tests/Unit/RequestTest.php

@@ -0,0 +1,138 @@
+<?php
+
+namespace Tests\Unit;
+
+use Exception;
+use Libs\Request;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+/**
+ * RequestTest - DuckBrain test harness
+ *
+ * Cubre el modelo de fallo por excepcion del Request: la validacion lanza
+ * con code 422 y el mensaje unico de Validator::message() (con overrides de
+ * messages()/attributes()), en lugar de responder HTTP y hacer exit() como
+ * hacia antes. Que estas pruebas puedan ejecutar expectException ya demuestra
+ * que el constructor no termina el proceso.
+ */
+final class RequestTest extends TestCase
+{
+    private array $serverBackup = [];
+    private array $getBackup = [];
+    private array $postBackup = [];
+
+    protected function setUp(): void
+    {
+        $this->serverBackup = $_SERVER;
+        $this->getBackup = $_GET;
+        $this->postBackup = $_POST;
+
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+        $_SERVER['REQUEST_URI'] = '/test';
+        $_SERVER['DOCUMENT_ROOT'] = '/nonexistent-docroot';
+        unset($_SERVER['CONTENT_TYPE'], $_SERVER['HTTP_ACCEPT']);
+        $_GET = [];
+        $_POST = [];
+    }
+
+    protected function tearDown(): void
+    {
+        $_SERVER = $this->serverBackup;
+        $_GET = $this->getBackup;
+        $_POST = $this->postBackup;
+    }
+
+    #[Test]
+    public function failedValidationThrowsWithHttp422Code(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_POST = ['age' => '5'];
+
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('The age must be at least 18.');
+        $this->expectExceptionCode(422);
+
+        new class extends Request {
+            public function rules(): array
+            {
+                return ['age' => 'required|min:18'];
+            }
+        };
+    }
+
+    #[Test]
+    public function messagesOverrideWinsForFailedRule(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_POST = ['age' => '5'];
+
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('Way too short');
+
+        new class extends Request {
+            public function rules(): array
+            {
+                return ['age' => 'required|min:18'];
+            }
+
+            public function messages(): array
+            {
+                return ['age.min' => 'Way too short'];
+            }
+        };
+    }
+
+    #[Test]
+    public function attributesRenameTheFieldInDefaultMessage(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_POST = ['age' => '5'];
+
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('The applicant age must be at least 18.');
+
+        new class extends Request {
+            public function rules(): array
+            {
+                return ['age' => 'required|min:18'];
+            }
+
+            public function attributes(): array
+            {
+                return ['age' => 'applicant age'];
+            }
+        };
+    }
+
+    #[Test]
+    public function getRulesFailureThrowsToo(): void
+    {
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('The q field is required.');
+
+        new class extends Request {
+            public function getRules(): array
+            {
+                return ['q' => 'required'];
+            }
+        };
+    }
+
+    #[Test]
+    public function validDataDoesNotThrow(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_POST = ['age' => '20'];
+
+        $request = new class extends Request {
+            public function rules(): array
+            {
+                return ['age' => 'required|min:18'];
+            }
+        };
+
+        $this->assertSame('20', $request->post->age);
+        $this->assertSame('/test', $request->path);
+    }
+}

tests/Unit/RouterTest.php

@@ -0,0 +1,317 @@
+<?php
+
+namespace Tests\Unit;
+
+use Exception;
+use Libs\Neuron;
+use Libs\Request;
+use Libs\Router;
+use LogicException;
+use PDOException;
+use PHPUnit\Framework\Attributes\RunInSeparateProcess;
+use PHPUnit\Framework\Attributes\Test;
+use ReflectionClass;
+use ReflectionProperty;
+use Tests\TestCase;
+use TypeError;
+
+/**
+ * RouterTest - DuckBrain test harness
+ *
+ * Cubre la respuesta de error que produce Router::defaultException(): el
+ * status derivado del code de la excepcion con guard de rango 400-599 y la
+ * negociacion por Accept entre representacion JSON y texto plano. Tambien la
+ * frontera de Router::apply(): que toda excepcion de la cadena (middlewares,
+ * callback final, notFound) llegue al $exceptionCallback deteniendo la
+ * ejecucion sin exit() y dejando intacto el flujo normal. Tambien que los
+ * valores por defecto declarados en las propiedades $notFoundCallback y
+ * $exceptionCallback (callables string) se resuelvan de punta a punta a
+ * traves de Synapsis::resolve() dentro de apply().
+ */
+final class RouterTest extends TestCase
+{
+    private array $serverBackup = [];
+    private array $getBackup = [];
+    private array $postBackup = [];
+
+    protected function setUp(): void
+    {
+        $this->serverBackup = $_SERVER;
+        $this->getBackup = $_GET;
+        $this->postBackup = $_POST;
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+        unset($_SERVER['HTTP_ACCEPT']);
+        @http_response_code(200); // Ver tearDown: inofensivo mientras no haya un header('HTTP/...') activo.
+        $this->resetRouterState();
+    }
+
+    protected function tearDown(): void
+    {
+        $_SERVER = $this->serverBackup;
+        $_GET = $this->getBackup;
+        $_POST = $this->postBackup;
+        // El @ cubre el warning de PHP 8.5 ("...has no effect") que dispara
+        // cualquier http_response_code() posterior a un header('HTTP/...'),
+        // inevitable en el proceso aislado del test de notFound (el valor
+        // se aplica igualmente, como confirma el getter).
+        @http_response_code(200);
+        $this->resetRouterState();
+    }
+
+    private function resetRouterState(): void
+    {
+        foreach (['get', 'post', 'put', 'patch', 'delete'] as $method) {
+            (new ReflectionProperty(Router::class, $method))->setValue(null, []);
+        }
+        Router::$params = new Neuron();
+        Router::$notFoundCallback = 'Libs\Router::defaultNotFound';
+        Router::$exceptionCallback = 'Libs\Router::defaultException';
+    }
+
+    private function render(\Throwable $exception): string
+    {
+        ob_start();
+        Router::defaultException($exception);
+
+        return ob_get_clean();
+    }
+
+    #[Test]
+    public function intCodeInHttpStatusRangeBecomesResponseStatus(): void
+    {
+        $output = $this->render(new Exception('The edad must be at least 18.', 422));
+
+        $this->assertSame(422, http_response_code());
+        $this->assertStringContainsString('The edad must be at least 18.', $output);
+    }
+
+    #[Test]
+    public function stringSqlStateCodeFallsBackToServerError(): void
+    {
+        $this->render(new PDOException('SQLSTATE[23000]: Integrity constraint violation', '23000'));
+
+        $this->assertSame(500, http_response_code(), 'A string SQLSTATE code must never reach http_response_code');
+    }
+
+    #[Test]
+    public function intCodeOutOfRangeFallsBackToServerError(): void
+    {
+        $this->render(new Exception('arbitrary code', 7));
+
+        $this->assertSame(500, http_response_code());
+    }
+
+    #[Test]
+    public function throwableWithoutMeaningfulCodeAnswersServerError(): void
+    {
+        $this->render(new TypeError('must be of the type int'));
+
+        $this->assertSame(500, http_response_code());
+    }
+
+    #[Test]
+    public function plainTextIsDefaultRepresentation(): void
+    {
+        $output = $this->render(new Exception('boom', 418));
+
+        $this->assertStringStartsWith("boom\n", $output);
+        $this->assertStringContainsString('#0', $output, 'Plain text must include the full trace');
+    }
+
+    #[Test]
+    public function jsonRepresentationWhenClientAcceptsJson(): void
+    {
+        $_SERVER['HTTP_ACCEPT'] = 'application/json';
+
+        $output = $this->render(new Exception('The e must be a valid email address.', 422));
+
+        $payload = json_decode($output, true);
+        $this->assertIsArray($payload, 'Accept: application/json must produce a JSON body');
+        $this->assertSame(422, http_response_code());
+        $this->assertSame('The e must be a valid email address.', $payload['error']);
+        $this->assertSame('Exception', $payload['exception']);
+        $this->assertArrayHasKey('file', $payload);
+        $this->assertArrayHasKey('line', $payload);
+        $this->assertIsArray($payload['trace']);
+        $this->assertIsString($payload['trace'][0], 'The trace must be serialized as readable lines, not raw frames');
+    }
+
+    #[Test]
+    public function middlewareExceptionStopsTheRemainingChain(): void
+    {
+        $log = [];
+        $caught = [];
+        Router::$exceptionCallback = function (\Throwable $exception) use (&$caught): void {
+            $caught[] = $exception;
+        };
+
+        Router::get('/chain', function () use (&$log): void {
+            $log[] = 'final';
+        });
+        Router::middleware(function () use (&$log): void {
+            $log[] = 'mw-late-registered';
+        });
+        Router::middleware(function () use (&$log): void {
+            throw new Exception('chain break', 422);
+        });
+        Router::middleware(function () use (&$log): void {
+            $log[] = 'mw-first-registered';
+        });
+
+        Router::apply('/chain');
+
+        // Callbacks run in reverse registration order: the last registered middleware
+        // ran first, the thrower stopped everything after it, and apply() returned
+        // normally (this line being reached proves there was no exit()).
+        $this->assertSame(['mw-first-registered'], $log);
+        $this->assertCount(1, $caught, 'The route chain must deliver exactly one exception to the callback');
+        $this->assertSame('chain break', $caught[0]->getMessage());
+        $this->assertSame(422, $caught[0]->getCode());
+    }
+
+    #[Test]
+    public function finalCallbackExceptionIsDeliveredToTheExceptionCallback(): void
+    {
+        $caught = [];
+        Router::$exceptionCallback = function (\Throwable $exception) use (&$caught): void {
+            $caught[] = get_class($exception) . ': ' . $exception->getMessage();
+        };
+
+        Router::get('/throwing', function (): void {
+            throw new LogicException('controller boom');
+        });
+
+        Router::apply('/throwing');
+
+        $this->assertSame(['LogicException: controller boom'], $caught);
+    }
+
+    #[Test]
+    public function notFoundCallbackExceptionReachesTheExceptionCallback(): void
+    {
+        $caught = [];
+        Router::$exceptionCallback = function (\Throwable $exception) use (&$caught): void {
+            $caught[] = $exception;
+        };
+        Router::$notFoundCallback = function (): void {
+            throw new Exception('not found exploded', 418);
+        };
+
+        Router::apply('/no-such-route');
+
+        $this->assertCount(1, $caught);
+        $this->assertSame('not found exploded', $caught[0]->getMessage());
+        $this->assertSame(418, $caught[0]->getCode());
+    }
+
+    #[Test]
+    public function normalFlowStillPrintsReturnedData(): void
+    {
+        Router::$exceptionCallback = function (): void {
+            $this->fail('The exception callback must not run on a successful request');
+        };
+
+        Router::get('/ok', function (): array {
+            return ['status' => 'ok'];
+        });
+
+        ob_start();
+        Router::apply('/ok');
+        $output = ob_get_clean();
+
+        $this->assertSame('{"status":"ok"}', $output);
+        $this->assertSame(200, http_response_code());
+    }
+
+    #[Test]
+    public function customOnInvalidExceptionReachesTheExceptionCallbackThroughTheBoundary(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'POST';
+        $_SERVER['REQUEST_URI'] = '/signup';
+        $_SERVER['DOCUMENT_ROOT'] = '/nonexistent-docroot';
+        $_POST = ['age' => '5'];
+
+        $caught = [];
+        Router::$exceptionCallback = function (\Throwable $exception) use (&$caught): void {
+            $caught[] = $exception;
+        };
+
+        $finalRan = false;
+        Router::post('/signup', function (StrictSignup $request) use (&$finalRan): void {
+            $finalRan = true;
+        });
+
+        Router::apply('/signup');
+
+        // The Request was built by the container for the final callback and its
+        // custom onInvalid() threw during dependency resolution: the custom type
+        // must arrive intact to the callback, and the final callback must not run.
+        $this->assertCount(1, $caught);
+        $this->assertInstanceOf(RequestRejected::class, $caught[0]);
+        $this->assertSame('The age must be at least 18.', $caught[0]->getMessage());
+        $this->assertSame(400, $caught[0]->getCode(), 'The status channel must survive custom exception types');
+        $this->assertFalse($finalRan, 'A Request that throws during DI resolution must stop the route');
+    }
+
+    #[Test]
+    public function declaredDefaultExceptionCallbackRendersThroughTheBoundary(): void
+    {
+        // Se fuerza el valor declarado en la clase, no el que reasigna
+        // resetRouterState(): es justo el camino property default ->
+        // Synapsis::resolve(string callable) que debe seguir funcionando.
+        Router::$exceptionCallback = (new ReflectionClass(Router::class))
+            ->getDefaultProperties()['exceptionCallback'];
+
+        Router::get('/default-exception', function (): void {
+            throw new Exception('rendered by the default handler', 422);
+        });
+
+        ob_start();
+        Router::apply('/default-exception');
+        $output = ob_get_clean();
+
+        $this->assertSame(422, http_response_code(), 'The declared default handler must derive the status from the code');
+        $this->assertStringContainsString('rendered by the default handler', $output);
+        $this->assertStringContainsString('#0', $output, 'The declared default handler must render the plain text trace');
+    }
+
+    #[Test]
+    #[RunInSeparateProcess]
+    public function declaredDefaultNotFoundCallbackRendersThe404Body(): void
+    {
+        Router::$notFoundCallback = (new ReflectionClass(Router::class))
+            ->getDefaultProperties()['notFoundCallback'];
+
+        ob_start();
+        Router::apply('/no-such-route');
+        $output = ob_get_clean();
+
+        // Proceso aislado: defaultNotFound() emite header('HTTP/1.0 404 ...') y en
+        // PHP 8.5 eso hace que TODO http_response_code() posterior avise, sin forma
+        // de limpiar el estado en el mismo proceso. En CLI el header no toca
+        // http_response_code(), asi que la asercion util es el cuerpo renderizado.
+        $this->assertStringContainsString('Error 404 - Page Not Found', $output);
+    }
+}
+
+// phpcs:disable PSR1.Classes.ClassDeclaration.MultipleClasses
+/**
+ * Fixtures locales de la prueba de simetría: un tipo de excepcion propio que
+ * un Request hijo lanza desde su onInvalid() reescrito.
+ */
+final class RequestRejected extends Exception
+{
+}
+
+final class StrictSignup extends Request
+{
+    public function rules(): array
+    {
+        return ['age' => 'required|min:18'];
+    }
+
+    public function onInvalid(string $error): never
+    {
+        throw new RequestRejected($error, 400);
+    }
+}

tests/Unit/SynapsisTest.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace Tests\Unit;
+
+use Exception;
+use Libs\Neuron;
+use Libs\Synapsis;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+/**
+ * SynapsisTest - DuckBrain test harness
+ *
+ * Cubre la inyeccion de argumentos por nombre en resolve(): la clave de
+ * $named gana sobre el default de un opcional y sobre la resolucion DI por
+ * tipo, la coincidencia es por nombre y no por posicion, y las claves
+ * sobrantes se ignoran en silencio (riesgo documentado en design.md).
+ */
+final class SynapsisTest extends TestCase
+{
+    #[Test]
+    public function namedValueWinsOverOptionalDefault(): void
+    {
+        $result = Synapsis::resolve(
+            fn ($config = 'default') => $config,
+            ['config' => 'forced']
+        );
+
+        $this->assertSame('forced', $result, 'A named argument must take precedence over an optional default');
+    }
+
+    #[Test]
+    public function namedValueWinsOverTypeBasedResolution(): void
+    {
+        $real = new Exception('the real one', 422);
+
+        $result = Synapsis::resolve(
+            fn (Exception $exception) => $exception,
+            ['exception' => $real]
+        );
+
+        $this->assertSame($real, $result, 'The injected instance must be the named one, not a container-built empty Exception');
+    }
+
+    #[Test]
+    public function namedParametersMatchByNameNotPosition(): void
+    {
+        $real = new Exception('matched by name');
+
+        [$b, $exception] = Synapsis::resolve(
+            fn (Neuron $b, Exception $exception) => [$b, $exception],
+            ['exception' => $real]
+        );
+
+        $this->assertInstanceOf(Neuron::class, $b, 'Parameters without a named match must keep resolving through DI');
+        $this->assertSame($real, $exception, 'Position of the named parameter must not matter');
+    }
+
+    #[Test]
+    public function unmatchedNamedKeysAreIgnored(): void
+    {
+        $result = Synapsis::resolve(
+            fn ($x = 'untouched') => $x,
+            ['foo' => 1]
+        );
+
+        $this->assertSame('untouched', $result, 'A key matching no parameter must be silently ignored');
+    }
+
+    #[Test]
+    public function renamedParameterFallsBackToContainerResolution(): void
+    {
+        $real = new Exception('never arrives');
+
+        // The handler renamed its parameter to $e, so the 'exception' key
+        // matches nothing and $e degrades to DI: a fresh empty Exception.
+        $result = Synapsis::resolve(
+            fn (Exception $e) => $e,
+            ['exception' => $real]
+        );
+
+        $this->assertNotSame($real, $result, 'A renamed handler parameter must not receive the named value');
+        $this->assertSame('', $result->getMessage(), 'The degradation outcome is a container-built empty Exception');
+    }
+}

tests/Unit/ValidatorTest.php

@@ -0,0 +1,192 @@
+<?php
+
+namespace Tests\Unit;
+
+use PHPUnit\Framework\Attributes\Test;
+use Libs\Neuron;
+use Libs\Validator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Tests\TestCase;
+
+/**
+ * ValidatorTest - DuckBrain test harness
+ *
+ * Regression net de las reglas escalares, el batch validateList()
+ * (paro en el primer fallo + $lastFailed) y message(). Las reglas de
+ * archivo (file/image/mimes) requieren fixtures de $_FILES y se dejan
+ * para la suite multi-motor de integración.
+ */
+final class ValidatorTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Validator::$lastFailed = '';
+    }
+
+    public static function scalarRuleProvider(): array
+    {
+        return [
+            'valid email'           => ['email', 'kj@duckbrain.dev', true],
+            'invalid email'         => ['email', 'not-an-email', false],
+            'valid url'             => ['url', 'https://kj2.me', true],
+            'invalid url'           => ['url', 'kj2.me', false],
+            'int from string'       => ['int', '42', true],
+            'int with decimals'      => ['int', '42.5', false],
+            'float'                  => ['float', '3.14', true],
+            'number e-notation'      => ['number', '1e3', true],
+            'bool yes'               => ['bool', 'yes', true],
+            'bool garbage'            => ['bool', 'quizas', false],
+            'strict string'        => ['string', '42', true],
+            'string rejects int'     => ['string', 42, false],
+            'array'                  => ['array', [1], true],
+            'array rejects string'   => ['array', 'x', false],
+        ];
+    }
+
+    #[DataProvider('scalarRuleProvider')]
+    #[Test]
+    public function scalarRules(string $rule, mixed $value, bool $expected): void
+    {
+        $this->assertSame($expected, Validator::checkRule($value, $rule), "rule {$rule} with " . var_export($value, true));
+    }
+
+    #[Test]
+
+    public function existsAndRequiredDisagreeOnEmptyString(): void
+    {
+        $this->assertTrue(Validator::checkRule('', 'exists'));
+        $this->assertFalse(Validator::checkRule('', 'required'));
+        $this->assertFalse(Validator::checkRule(null, 'exists'));
+    }
+
+    #[Test]
+
+    public function sizeRulesMeasureStringNumberAndArray(): void
+    {
+        $this->assertTrue(Validator::checkRule('abc', 'min:3'));
+        $this->assertFalse(Validator::checkRule('abc', 'min:4'));
+        $this->assertTrue(Validator::checkRule(10, 'max:10'));
+        $this->assertTrue(Validator::checkRule([1, 2, 3], 'between:2,3'));
+        $this->assertTrue(Validator::checkRule('hey', 'size:3'));
+        $this->assertFalse(Validator::checkRule('hey', 'size:4'));
+    }
+
+    #[Test]
+
+    public function regexKeepsColonsAndCommasInsidePattern(): void
+    {
+        $this->assertTrue(Validator::checkRule('a,b', 'regex:/^a,b$/'));
+        $this->assertFalse(Validator::checkRule('a;b', 'regex:/^a,b$/'));
+    }
+
+    #[Test]
+
+    public function enumIsLooseComparison(): void
+    {
+        $this->assertTrue(Validator::checkRule('1', 'enum:1,2,3'));
+        $this->assertFalse(Validator::checkRule('9', 'enum:1,2,3'));
+    }
+
+    #[Test]
+
+    public function notNegatesNextRule(): void
+    {
+        $this->assertTrue(Validator::checkRule('3.5', 'not:int'));
+        $this->assertFalse(Validator::checkRule('42', 'not:int'));
+    }
+
+    #[Test]
+
+    public function parseRule(): void
+    {
+        $this->assertSame(['required', ''], Validator::parseRule('required'));
+        $this->assertSame(['enum', 'a,b'], Validator::parseRule('enum:a,b'));
+        $this->assertSame(['regex', '/^a,b$/'], Validator::parseRule('regex:/^a,b$/'));
+    }
+
+    #[Test]
+
+    public function validateListPassesFullyValidBatch(): void
+    {
+        $data = new Neuron(['username' => 'kj', 'email' => 'kj@duckbrain.dev']);
+
+        $this->assertTrue(Validator::validateList(
+            ['username' => 'required|string|min:2', 'email' => 'required|email'],
+            $data
+        ));
+        $this->assertSame('', Validator::$lastFailed);
+    }
+
+    #[Test]
+
+    public function validateListStopsAtFirstFailure(): void
+    {
+        $data = new Neuron(['email' => 'not-an-email', 'name' => null]);
+
+        $this->assertFalse(Validator::validateList(
+            ['email' => 'required|email', 'name' => 'required'],
+            $data
+        ));
+        $this->assertSame('email.email', Validator::$lastFailed);
+    }
+
+    #[Test]
+
+    public function validateListNullableSkipsRestWhenEmpty(): void
+    {
+        $rules = ['bio' => 'nullable|min:10'];
+
+        $this->assertTrue(Validator::validateList($rules, new Neuron(['bio' => null])));
+        $this->assertFalse(Validator::validateList($rules, new Neuron(['bio' => 'too-short'])));
+    }
+
+    #[Test]
+
+    public function validateListConfirmedUsesSiblingField(): void
+    {
+        $rules = ['password' => 'required|confirmed'];
+
+        $ok = new Neuron(['password' => 'secret', 'password_confirmation' => 'secret']);
+        $bad = new Neuron(['password' => 'secret', 'password_confirmation' => 'different']);
+
+        $this->assertTrue(Validator::validateList($rules, $ok));
+        $this->assertFalse(Validator::validateList($rules, $bad));
+        $this->assertSame('password.confirmed', Validator::$lastFailed);
+    }
+
+    #[Test]
+
+    public function messageBuildsHumanTextFromLastFailed(): void
+    {
+        $this->assertSame(
+            'The email must be a valid email address.',
+            Validator::message('email.email')
+        );
+        $this->assertSame(
+            'The age must be between 5 and 10.',
+            Validator::message('age.between:5,10')
+        );
+        $this->assertSame(
+            'The selected status is invalid. Allowed: a, b, c.',
+            Validator::message('status.enum:a,b,c')
+        );
+        $this->assertSame(
+            'The reason field is required when mode is other.',
+            Validator::message('reason.required_if:mode,other')
+        );
+    }
+
+    #[Test]
+
+    public function messageRespectsAttributesAndOverrides(): void
+    {
+        $this->assertSame(
+            'The user name field is required.',
+            Validator::message('username.required', [], ['username' => 'user name'])
+        );
+        $this->assertSame(
+            'custom',
+            Validator::message('username.min:3', ['username.min:3' => 'custom'])
+        );
+    }
+}

tests/bootstrap.php

@@ -0,0 +1,56 @@
+<?php
+
+// Test bootstrap for the DuckBrain development harness.
+// Run PHPUnit from the project root (autoload.php resolves config.php via cwd).
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+// Engine selection: DUCKBRAIN_TEST_DB=sqlite|mysql|pgsql (default: sqlite).
+// sqlite uses an in-memory database, so the unit suite never needs services.
+$engine = strtolower(getenv('DUCKBRAIN_TEST_DB') ?: 'sqlite');
+
+$profiles = [
+    'sqlite' => [
+        'type' => 'sqlite',
+        'host' => 'localhost',
+        'name' => ':memory:',
+        'user' => '',
+        'pass' => '',
+    ],
+    'mysql' => [
+        'type' => 'mysql',
+        'host' => '127.0.0.1',
+        'name' => 'duckbrain_test',
+        'user' => 'duckbrain',
+        'pass' => 'duckbrain',
+    ],
+    'pgsql' => [
+        'type' => 'pgsql',
+        'host' => '127.0.0.1',
+        'name' => 'duckbrain_test',
+        'user' => 'duckbrain',
+        'pass' => 'duckbrain',
+    ],
+];
+
+if (!isset($profiles[$engine])) {
+    fwrite(
+        STDERR,
+        "Invalid DUCKBRAIN_TEST_DB '{$engine}'. Expected one of: "
+        . implode(', ', array_keys($profiles)) . "\n"
+    );
+    exit(1);
+}
+
+// Define DB constants BEFORE config.php so the test database wins over the
+// real configuration (config.php's define() warnings are suppressed by @).
+// Each field can be overridden without losing the engine's other defaults.
+$profile = $profiles[$engine];
+
+define('DB_TYPE', $profile['type']);
+define('DB_HOST', getenv('DUCKBRAIN_TEST_HOST') ?: $profile['host']);
+define('DB_NAME', getenv('DUCKBRAIN_TEST_NAME') ?: $profile['name']);
+define('DB_USER', getenv('DUCKBRAIN_TEST_USER') ?: $profile['user']);
+define('DB_PASS', getenv('DUCKBRAIN_TEST_PASS') ?: $profile['pass']);
+
+@require_once __DIR__ . '/../autoload.php';