Writing Integration Tests Against a Temporary Database

Create a disposable SQLite database or isolated test instance and assert real SQL behavior.

The objective is to understand the behavior and operational limits, not only the method name.

What It Does

Create a disposable SQLite database or isolated test instance and assert real SQL behavior.

Prerequisites

Use a dedicated development environment and sample data. Where a snippet uses an injected connection, repository, request value or mailer, supply it from your own application setup.

Example 1: Basic Use

A focused working pattern for this topic. Names such as $pdo, $authContext and $repo represent dependencies provided by the application unless initialized in the snippet.

<?php
$db = new PDO('sqlite::memory:');
$db->exec('CREATE TABLE tokens (id INTEGER PRIMARY KEY, value TEXT UNIQUE)');
$db->prepare('INSERT INTO tokens (value) VALUES (?)')->execute(['test-token']);
assert($db->query('SELECT COUNT(*) FROM tokens')->fetchColumn() == 1);

Example 2: A Second Scenario

A second use case that adds a different operation or data flow specific to this topic.

<?php
$db = new PDO('sqlite::memory:',null,null,[PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION]);
$db->exec('CREATE TABLE emails (address TEXT UNIQUE)');
$db->prepare('INSERT INTO emails VALUES (?)')->execute(['[email protected]']);
assert((int)$db->query('SELECT COUNT(*) FROM emails')->fetchColumn() === 1);

Example 3: Practical Checks

A practical validation, failure or deployment concern specific to this topic.

<?php
$db = new PDO('sqlite::memory:');
$db->exec('CREATE TABLE parts (id INTEGER PRIMARY KEY, qty INTEGER)');
$db->prepare('INSERT INTO parts VALUES (?,?)')->execute([10, 5]);
assert((int)$db->query('SELECT qty FROM parts WHERE id=10')->fetchColumn() === 5);

Important Behavior and Edge Cases

A production schema, migrations and driver differences can still require a separate database-specific test suite.

For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.

Comparison with Related Approaches

Common Beginner Mistakes

Key Takeaways

• Create a disposable SQLite database or isolated test instance and assert real SQL behavior.
• A production schema, migrations and driver differences can still require a separate database-specific test suite.
• Use this workflow as a focused starting point rather than a substitute for application-level tests.

Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.