testGetMimeTypeByExtension(); $this->testGetExtensionByMimeType(); } public function testGetMimeTypeByExtension() { // Test when extension exists $this->assertEquals('text/x-php', MimeType::getMimeTypeByExtension('php')); $this->assertNull(MimeType::getMimeTypeByExtension('unknown_extension')); } public function testGetExtensionByMimeType() { $this->assertEquals('php', MimeType::getExtensionByMimeType('text/x-php')); $this->assertNull(MimeType::getExtensionByMimeType('unknown_mime_type')); } }