diff --git a/tests/Service/DumpFilenameParserTest.php b/tests/Service/DumpFilenameParserTest.php
new file mode 100644
index 0000000..354b1e5
--- /dev/null
+++ b/tests/Service/DumpFilenameParserTest.php
@@ -0,0 +1,54 @@
+<?php declare(strict_types=1);
+
+namespace AeonDumpManager\Tests\Service;
+
+use AeonDumpManager\Service\DumpFilenameParser;
+use PHPUnit\Framework\TestCase;
+
+class DumpFilenameParserTest extends TestCase
+{
+    private DumpFilenameParser $parser;
+
+    protected function setUp(): void
+    {
+        $this->parser = new DumpFilenameParser();
+    }
+
+    public function testFormatProducesExpectedPattern(): void
+    {
+        $dateTime = new \DateTimeImmutable('2026-09-14 15:04:05');
+
+        self::assertSame('dump_2026-09-14_15-04-05.sql.gz', $this->parser->format($dateTime));
+    }
+
+    public function testParseRoundTripsWithFormat(): void
+    {
+        $dateTime = new \DateTimeImmutable('2026-09-14 15:04:05');
+        $filename = $this->parser->format($dateTime);
+
+        self::assertEquals($dateTime, $this->parser->parse($filename));
+    }
+
+    /**
+     * @dataProvider invalidFilenameProvider
+     */
+    public function testParseRejectsInvalidFilenames(string $filename): void
+    {
+        self::assertNull($this->parser->parse($filename));
+    }
+
+    public static function invalidFilenameProvider(): iterable
+    {
+        yield 'wrong extension' => ['dump_2026-09-14_15-04-05.sql'];
+        yield 'no prefix' => ['2026-09-14_15-04-05.sql.gz'];
+        yield 'path traversal' => ['../dump_2026-09-14_15-04-05.sql.gz'];
+        yield 'garbage' => ['not-a-dump.sql.gz'];
+        yield 'empty' => [''];
+    }
+
+    public function testIsValid(): void
+    {
+        self::assertTrue($this->parser->isValid('dump_2026-09-14_15-04-05.sql.gz'));
+        self::assertFalse($this->parser->isValid('../etc/passwd'));
+    }
+}
diff --git a/tests/Service/MySqlVariantTest.php b/tests/Service/MySqlVariantTest.php
new file mode 100644
index 0000000..fb6020c
--- /dev/null
+++ b/tests/Service/MySqlVariantTest.php
@@ -0,0 +1,25 @@
+<?php declare(strict_types=1);
+
+namespace AeonDumpManager\Tests\Service;
+
+use AeonDumpManager\Service\MySqlVariant;
+use PHPUnit\Framework\TestCase;
+
+class MySqlVariantTest extends TestCase
+{
+    /**
+     * @dataProvider versionProvider
+     */
+    public function testIsMariaDb(string $version, bool $expected): void
+    {
+        self::assertSame($expected, MySqlVariant::isMariaDb($version));
+    }
+
+    public static function versionProvider(): iterable
+    {
+        yield 'plain mysql' => ['8.0.36', false];
+        yield 'mariadb with legacy prefix' => ['5.5.5-10.11.2-MariaDB', true];
+        yield 'mariadb without legacy prefix' => ['10.11.2-MariaDB', true];
+        yield 'mariadb lowercase' => ['10.11.2-mariadb', true];
+    }
+}