Add a test logger

This is meant to make it easier to do unit tests and also assert
what's in the log.

I know it's bad practices to test against implementation details but
sometimes there are not other good options

src/Logger/TestLogger.php

@@ -0,0 +1,87 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\Logger;
+
+use PHPUnit\Framework\Assert;
+use Psr\Log\AbstractLogger;
+use Psr\Log\LogLevel;
+
+/**
+ * @phpstan-type LogRecord array{
+ *      level: string,
+ *      message: string|\Stringable,
+ *      context: array<string, mixed>
+ *  }
+ */
+final class TestLogger extends AbstractLogger
+{
+	/** @var array<array-key, LogRecord> */
+	protected array $buffer = [];
+
+	/**
+	 * @inheritdoc
+	 * @phpstan-param LogLevel::* $level
+	 * @param array<string, mixed> $context
+	 */
+	public function log($level, string|\Stringable $message, array $context = []): void
+	{
+		$this->buffer[] = [
+			'level' => $level,
+			'message' => $message,
+			'context' => $context,
+		];
+	}
+
+	/**
+	 * @param int $index
+	 * @return false|LogRecord
+	 */
+	public function getLogAt(int $index): false|array
+	{
+		if (!isset($this->buffer[$index])) {
+			return false;
+		}
+
+		return $this->buffer[$index];
+	}
+
+	public function assertBufferContainsMessage(string $message, int $expectedCount = 1): void
+	{
+		$found = 0;
+		foreach ($this->buffer as $buffer) {
+			if ($buffer['message'] === $message) {
+				$found++;
+			}
+		}
+
+		Assert::assertSame($expectedCount, $found);
+	}
+
+	/**
+	 * @param \Closure(LogRecord): bool $check
+	 */
+	public function assertBufferContains(\Closure $check): void
+	{
+		$found = 0;
+		foreach ($this->buffer as $buffer) {
+			if ($check($buffer)) {
+				$found++;
+			}
+		}
+
+		Assert::assertTrue($found !== 0);
+	}
+
+	public function reset(): void
+	{
+		$this->buffer = [];
+	}
+
+	/**
+	 * @return array<array-key, LogRecord>
+	 */
+	public function getBuffer(): array
+	{
+		return $this->buffer;
+	}
+}

tests/Logger/TestLoggerTest.php

@@ -0,0 +1,50 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Logger\Logger;
+
+use PHPUnit\Framework\TestCase;
+
+final class TestLoggerTest extends TestCase
+{
+	public function testAssert(): void
+	{
+		$logger = new TestLogger();
+		$logger->debug('Test message');
+		$logger->info('Info message');
+		$logger->info('Info message');
+		$logger->error('Error message');
+
+		$logger->assertBufferContainsMessage('Info message', 2);
+	}
+
+	public function testCustomCheck(): void
+	{
+		$logger = new TestLogger();
+		$logger->debug('Test message', [
+			'test' => 1,
+		]);
+		$logger->notice('Test message', [
+			'test' => 1,
+		]);
+		$logger->info('Test message', [
+			'test' => 1,
+		]);
+		$logger->error('Test message', [
+			'test' => 1,
+		]);
+
+		$logger->assertBufferContains(fn (array $record) => $record['context']['test'] === 1);
+	}
+
+	public function testReset(): void
+	{
+		$logger = new TestLogger();
+		$logger->debug('Test message');
+
+		$this->assertCount(1, $logger->getBuffer());
+
+		$logger->reset();
+
+		$this->assertCount(0, $logger->getBuffer());
+	}
+}