diff --git a/tests/phpunit/mocks/DummyServicesTrait.php b/tests/phpunit/mocks/DummyServicesTrait.php
index c7864423546..ae6f9e865c5 100644
--- a/tests/phpunit/mocks/DummyServicesTrait.php
+++ b/tests/phpunit/mocks/DummyServicesTrait.php
@@ -205,6 +205,7 @@ trait DummyServicesTrait {
 	 * @param array $options Supported keys:
 	 *    - validInterwikis: array of interwiki info to pass to getDummyInterwikiLookup
 	 *    - throwMockExceptions: boolean, see above
+	 *    - any of the options passed to getDummyNamespaceInfo (the same $options is passed on)
 	 *
 	 * @return MediaWikiTitleCodec
 	 */
@@ -215,13 +216,10 @@ trait DummyServicesTrait {
 		];
 		$config = $options + $baseConfig;
 
-		$namespaceInfo = $this->getDummyNamespaceInfo();
+		$namespaceInfo = $this->getDummyNamespaceInfo( $options );
 
 		/** @var Language|MockObject $language */
-		$language = $this->createNoOpMock(
-			Language::class,
-			[ 'ucfirst', 'lc', 'getNsIndex', 'needsGenderDistinction', 'getNsText' ]
-		);
+		$language = $this->createMock( Language::class );
 		$language->method( 'ucfirst' )->willReturnCallback( 'ucfirst' );
 		$language->method( 'lc' )->willReturnCallback(
 			static function ( $str, $first ) {
@@ -263,7 +261,7 @@ trait DummyServicesTrait {
 		$language->method( 'needsGenderDistinction' )->willReturn( false );
 
 		/** @var GenderCache|MockObject $genderCache */
-		$genderCache = $this->createNoOpMock( GenderCache::class );
+		$genderCache = $this->createMock( GenderCache::class );
 
 		$interwikiLookup = $this->getDummyInterwikiLookup( $config['validInterwikis'] );
 
@@ -361,10 +359,17 @@ trait DummyServicesTrait {
 	}
 
 	/**
-	 * @param array $options Valid keys are any of the configuration options passed, plus
-	 *   'logger' (defaults to a NullLogger), 'validInterwikis' (defaults to 'interwiki'),
-	 *   and 'textFormatter' (defaults to a mock where the 'format' method (the only one
-	 *   used by UserNameUtils) just returns the key of the MessageValue provided)
+	 * @param array $options Supported keys:
+	 *   - any of the configuration options used in the ServiceOptions
+	 *   - logger: logger to use, defaults to a NullLogger
+	 *   - textFormatter: ITextFormatter to use, defaults to a mock where the 'format' method
+	 *     (the only one used by UserNameUtils) just returns the key of the MessageValue provided)
+	 *   - titleParser: TitleParser to use, otherwise we will use getDummyTitleParser()
+	 *   - any of the options passed to getDummyTitleParser (the same $options is passed on if
+	 *     no titleParser is provided) (we change the default for "validInterwikis" to be
+	 *     [ 'interwiki' ] instead of an empty array if not provided)
+	 *   - hookContainer: specific HookContainer to use, default to creating an empty one via
+	 *     $this->createHookContainer()
 	 * @return UserNameUtils
 	 */
 	private function getDummyUserNameUtils( array $options = [] ) {
@@ -385,7 +390,7 @@ trait DummyServicesTrait {
 		// create a mock in each test. Note that the actual Language::ucfirst is a bit
 		// more complicated than this, but since the tests are all in English the plain
 		// php `ucfirst` should be enough.
-		$contentLang = $this->createNoOpMock( Language::class, [ 'ucfirst' ] );
+		$contentLang = $this->createMock( Language::class, [ 'ucfirst' ] );
 		$contentLang->method( 'ucfirst' )
 			->willReturnCallback( static function ( $str ) {
 				return ucfirst( $str );
@@ -404,16 +409,21 @@ trait DummyServicesTrait {
 				);
 		}
 
-		// The TitleParser from DummyServicesTrait::getDummyTitleParser is really a
-		// MediaWikiTitleCodec object, and by passing `throwMockExceptions` we replace
-		// the actual creation of `MalformedTitleException`s with mocks - see
-		// MediaWikiTitleCodec::overrideCreateMalformedTitleExceptionCallback()
-		// The UserNameUtils code doesn't care about the message in the exception,
-		// just whether it is thrown.
-		$titleParser = $this->getDummyTitleParser( [
-			'validInterwikis' => ( $options['validInterwikis'] ?? [ 'interwiki' ] ),
-			'throwMockExceptions' => true,
-		] );
+		$titleParser = $options['titleParser'] ?? false;
+		if ( !$titleParser ) {
+			// The TitleParser from DummyServicesTrait::getDummyTitleParser is really a
+			// MediaWikiTitleCodec object, and by passing `throwMockExceptions` we replace
+			// the actual creation of `MalformedTitleException`s with mocks - see
+			// MediaWikiTitleCodec::overrideCreateMalformedTitleExceptionCallback()
+			// The UserNameUtils code doesn't care about the message in the exception,
+			// just whether it is thrown.
+			$titleParser = $this->getDummyTitleParser(
+				$options + [
+					'validInterwikis' => [ 'interwiki' ],
+					'throwMockExceptions' => true
+				]
+			);
+		}
 
 		return new UserNameUtils(
 			$serviceOptions,
@@ -421,7 +431,7 @@ trait DummyServicesTrait {
 			$logger,
 			$titleParser,
 			$textFormatter,
-			$this->createHookContainer()
+			$options['hookContainer'] ?? $this->createHookContainer()
 		);
 	}
 
diff --git a/tests/phpunit/includes/ParamValidator/TypeDef/UserDefTest.php b/tests/phpunit/unit/includes/ParamValidator/TypeDef/UserDefTest.php
similarity index 89%
rename from tests/phpunit/includes/ParamValidator/TypeDef/UserDefTest.php
rename to tests/phpunit/unit/includes/ParamValidator/TypeDef/UserDefTest.php
index ba7ca63a4b8..03494c67c79 100644
--- a/tests/phpunit/includes/ParamValidator/TypeDef/UserDefTest.php
+++ b/tests/phpunit/unit/includes/ParamValidator/TypeDef/UserDefTest.php
@@ -2,8 +2,8 @@
 
 namespace MediaWiki\ParamValidator\TypeDef;
 
-use MediaWiki\Interwiki\ClassicInterwikiLookup;
-use MediaWiki\MediaWikiServices;
+use MediaWiki\HookContainer\HookContainer;
+use MediaWiki\Tests\Unit\DummyServicesTrait;
 use MediaWiki\User\UserIdentity;
 use MediaWiki\User\UserIdentityLookup;
 use MediaWiki\User\UserIdentityValue;
@@ -14,11 +14,10 @@ use Wikimedia\ParamValidator\TypeDef\TypeDefTestCase;
 use Wikimedia\ParamValidator\ValidationException;
 
 /**
- * @TODO convert to a unit test, all dependencies are injected
- *
  * @covers MediaWiki\ParamValidator\TypeDef\UserDef
  */
 class UserDefTest extends TypeDefTestCase {
+	use DummyServicesTrait;
 
 	protected function getInstance( SimpleCallbacks $callbacks, array $options ) {
 		// The UserIdentityLookup that we have knows about 5 users, with ids
@@ -48,50 +47,32 @@ class UserDefTest extends TypeDefTestCase {
 				return null;
 			}
 		);
+
+		// DummyServicesTrait will call $this->createHookContainer() if we didn't pass
+		// one, but that method is only available from MediaWikiTestCaseTrait - just
+		// create a simple mock that doesn't do anything, because we
+		// don't care about hooks here
+		$hookContainer = $this->createMock( HookContainer::class );
+		$hookContainer->method( 'run' )->willReturn( true );
+		// We can throw mock exceptions because the UserDef code doesn't care about
+		// the messages in the exceptions, just if they are thrown
+		$titleParser = $this->getDummyTitleParser( [
+			'validInterwikis' => [ 'interwiki' ],
+			'throwMockExceptions' => true,
+			'hookContainer' => $hookContainer, // for the NamespaceInfo
+		] );
+		$userNameUtils = $this->getDummyUserNameUtils( [
+			'titleParser' => $titleParser, // don't create a new one
+			'hookContainer' => $hookContainer,
+		] );
 		return new UserDef(
 			$callbacks,
 			$userIdentityLookup,
-			MediaWikiServices::getInstance()->getTitleParser(),
-			MediaWikiServices::getInstance()->getUserNameUtils()
+			$titleParser,
+			$userNameUtils
 		);
 	}
 
-	private $wgInterwikiCache = null;
-
-	protected function setUp(): void {
-		global $wgInterwikiCache;
-
-		parent::setUp();
-
-		// We don't have MediaWikiIntegrationTestCase's methods available, so we have to do it ourself.
-		$this->wgInterwikiCache = $wgInterwikiCache;
-		$wgInterwikiCache = ClassicInterwikiLookup::buildCdbHash( [
-			[
-				'iw_prefix' => 'interwiki',
-				'iw_url' => 'http://example.com/',
-				'iw_local' => 0,
-				'iw_trans' => 0,
-			],
-		] );
-		// UserNameUtils holds TitleParser (aka _MediaWikiTitleCodec) holds InterwikiLookup
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'InterwikiLookup' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( '_MediaWikiTitleCodec' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'TitleParser' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'UserNameUtils' );
-	}
-
-	protected function tearDown(): void {
-		global $wgInterwikiCache;
-
-		$wgInterwikiCache = $this->wgInterwikiCache;
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'InterwikiLookup' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( '_MediaWikiTitleCodec' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'TitleParser' );
-		MediaWikiServices::getInstance()->resetServiceForTesting( 'UserNameUtils' );
-
-		parent::tearDown();
-	}
-
 	public function provideValidate() {
 		// General tests of string inputs
 		$data = [