diff --git a/polygerrit-ui/app/utils/display-name-util_test.js b/polygerrit-ui/app/utils/display-name-util_test.js
deleted file mode 100644
index 9bb68dc..0000000
--- a/polygerrit-ui/app/utils/display-name-util_test.js
+++ /dev/null
@@ -1,200 +0,0 @@
-/**
- * @license
- * Copyright (C) 2019 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-import '../test/common-test-setup-karma.js';
-import {getDisplayName, getUserName, getGroupDisplayName, getAccountDisplayName, _testOnly_accountEmail} from './display-name-util.js';
-
-suite('display-name-utils tests', () => {
-  // eslint-disable-next-line no-unused-vars
-  const config = {
-    user: {
-      anonymous_coward_name: 'Anonymous Coward',
-    },
-  };
-
-  test('getDisplayName name only', () => {
-    const account = {
-      name: 'test-name',
-    };
-    assert.equal(getDisplayName(config, account),
-        'test-name');
-  });
-
-  test('getDisplayName prefer displayName', () => {
-    const account = {
-      name: 'test-name',
-      display_name: 'better-name',
-    };
-    assert.equal(getDisplayName(config, account),
-        'better-name');
-  });
-
-  test('getDisplayName prefer username default', () => {
-    const account = {
-      name: 'test-name',
-      username: 'user-name',
-    };
-    const config = {
-      accounts: {
-        default_display_name: 'USERNAME',
-      },
-    };
-    assert.equal(getDisplayName(config, account),
-        'user-name');
-  });
-
-  test('getDisplayName firstNameOnly', () => {
-    const account = {
-      name: 'firstname lastname',
-    };
-    assert.equal(getDisplayName(config, account, true), 'firstname');
-  });
-
-  test('getDisplayName prefer first name default', () => {
-    const account = {
-      name: 'firstname lastname',
-    };
-    const config = {
-      accounts: {
-        default_display_name: 'FIRST_NAME',
-      },
-    };
-    assert.equal(getDisplayName(config, account),
-        'firstname');
-  });
-
-  test('getDisplayName ignore leading whitespace for first name', () => {
-    const account = {
-      name: '   firstname lastname',
-    };
-    const config = {
-      accounts: {
-        default_display_name: 'FIRST_NAME',
-      },
-    };
-    assert.equal(getDisplayName(config, account),
-        'firstname');
-  });
-
-  test('getDisplayName full name default', () => {
-    const account = {
-      name: 'firstname lastname',
-    };
-    const config = {
-      accounts: {
-        default_display_name: 'FULL_NAME',
-      },
-    };
-    assert.equal(getDisplayName(config, account),
-        'firstname lastname');
-  });
-
-  test('getDisplayName name only', () => {
-    const account = {
-      name: 'test-name',
-    };
-    assert.deepEqual(getUserName(config, account),
-        'test-name');
-  });
-
-  test('getUserName username only', () => {
-    const account = {
-      username: 'test-user',
-    };
-    assert.deepEqual(getUserName(config, account),
-        'test-user');
-  });
-
-  test('getUserName email only', () => {
-    const account = {
-      email: 'test-user@test-url.com',
-    };
-    assert.deepEqual(getUserName(config, account),
-        'test-user@test-url.com');
-  });
-
-  test('getUserName returns not Anonymous Coward as the anon name', () => {
-    assert.deepEqual(getUserName(config, null),
-        'Anonymous');
-  });
-
-  test('getUserName for the config returning the anon name', () => {
-    const config = {
-      user: {
-        anonymous_coward_name: 'Test Anon',
-      },
-    };
-    assert.deepEqual(getUserName(config, null),
-        'Test Anon');
-  });
-
-  test('getAccountDisplayName - account with name only', () => {
-    assert.equal(
-        getAccountDisplayName(config,
-            {name: 'Some user name'}),
-        'Some user name');
-  });
-
-  test('getAccountDisplayName - account with email only', () => {
-    assert.equal(
-        getAccountDisplayName(config,
-            {email: 'my@example.com'}),
-        'my@example.com <my@example.com>');
-  });
-
-  test('getAccountDisplayName - account with name and status', () => {
-    assert.equal(
-        getAccountDisplayName(config, {
-          name: 'Some name',
-          status: 'OOO',
-        }),
-        'Some name (OOO)');
-  });
-
-  test('getAccountDisplayName - account with name and email', () => {
-    assert.equal(
-        getAccountDisplayName(config, {
-          name: 'Some name',
-          email: 'my@example.com',
-        }),
-        'Some name <my@example.com>');
-  });
-
-  test('getAccountDisplayName - account with name, email and status', () => {
-    assert.equal(
-        getAccountDisplayName(config, {
-          name: 'Some name',
-          email: 'my@example.com',
-          status: 'OOO',
-        }),
-        'Some name <my@example.com> (OOO)');
-  });
-
-  test('getGroupDisplayName', () => {
-    assert.equal(
-        getGroupDisplayName({name: 'Some user name'}),
-        'Some user name (group)');
-  });
-
-  test('_accountEmail', () => {
-    assert.equal(
-        _testOnly_accountEmail('email@gerritreview.com'),
-        '<email@gerritreview.com>');
-    assert.equal(_testOnly_accountEmail(undefined), '');
-  });
-});
-
diff --git a/polygerrit-ui/app/utils/display-name-util_test.ts b/polygerrit-ui/app/utils/display-name-util_test.ts
new file mode 100644
index 0000000..e6d4704
--- /dev/null
+++ b/polygerrit-ui/app/utils/display-name-util_test.ts
@@ -0,0 +1,225 @@
+/**
+ * @license
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  AccountInfo,
+  DefaultDisplayNameConfig,
+  EmailAddress,
+  GroupName,
+  ServerInfo,
+} from '../api/rest-api';
+import '../test/common-test-setup-karma';
+import {
+  getDisplayName,
+  getUserName,
+  getGroupDisplayName,
+  getAccountDisplayName,
+  _testOnly_accountEmail,
+} from './display-name-util';
+import {
+  createAccountsConfig,
+  createGroupInfo,
+  createServerInfo,
+} from '../test/test-data-generators';
+
+suite('display-name-utils tests', () => {
+  const config: ServerInfo = {
+    ...createServerInfo(),
+    user: {
+      anonymous_coward_name: 'Anonymous Coward',
+    },
+  };
+
+  test('getDisplayName name only', () => {
+    const account = {
+      name: 'test-name',
+    };
+    assert.equal(getDisplayName(config, account), 'test-name');
+  });
+
+  test('getDisplayName prefer displayName', () => {
+    const account = {
+      name: 'test-name',
+      display_name: 'better-name',
+    };
+    assert.equal(getDisplayName(config, account), 'better-name');
+  });
+
+  test('getDisplayName prefer username default', () => {
+    const account = {
+      name: 'test-name',
+      username: 'user-name',
+    };
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      accounts: {
+        ...createAccountsConfig(),
+        default_display_name: DefaultDisplayNameConfig.USERNAME,
+      },
+    };
+    assert.equal(getDisplayName(config, account), 'user-name');
+  });
+
+  test('getDisplayName firstNameOnly', () => {
+    const account = {
+      name: 'firstname lastname',
+    };
+    assert.equal(getDisplayName(config, account, true), 'firstname');
+  });
+
+  test('getDisplayName prefer first name default', () => {
+    const account = {
+      name: 'firstname lastname',
+    };
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      accounts: {
+        ...createAccountsConfig(),
+        default_display_name: DefaultDisplayNameConfig.FIRST_NAME,
+      },
+    };
+    assert.equal(getDisplayName(config, account), 'firstname');
+  });
+
+  test('getDisplayName ignore leading whitespace for first name', () => {
+    const account = {
+      name: '   firstname lastname',
+    };
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      accounts: {
+        ...createAccountsConfig(),
+        default_display_name: DefaultDisplayNameConfig.FIRST_NAME,
+      },
+    };
+    assert.equal(getDisplayName(config, account), 'firstname');
+  });
+
+  test('getDisplayName full name default', () => {
+    const account = {
+      name: 'firstname lastname',
+    };
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      accounts: {
+        ...createAccountsConfig(),
+        default_display_name: DefaultDisplayNameConfig.FULL_NAME,
+      },
+    };
+    assert.equal(getDisplayName(config, account), 'firstname lastname');
+  });
+
+  test('getDisplayName name only', () => {
+    const account = {
+      name: 'test-name',
+    };
+    assert.deepEqual(getUserName(config, account), 'test-name');
+  });
+
+  test('getUserName username only', () => {
+    const account = {
+      username: 'test-user',
+    };
+    assert.deepEqual(getUserName(config, account), 'test-user');
+  });
+
+  test('getUserName email only', () => {
+    const account: AccountInfo = {
+      email: 'test-user@test-url.com' as EmailAddress,
+    };
+    assert.deepEqual(getUserName(config, account), 'test-user@test-url.com');
+  });
+
+  test('getUserName returns not Anonymous Coward as the anon name', () => {
+    assert.deepEqual(getUserName(config, undefined), 'Anonymous');
+  });
+
+  test('getUserName for the config returning the anon name', () => {
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      user: {
+        anonymous_coward_name: 'Test Anon',
+      },
+    };
+    assert.deepEqual(getUserName(config, undefined), 'Test Anon');
+  });
+
+  test('getAccountDisplayName - account with name only', () => {
+    assert.equal(
+      getAccountDisplayName(config, {name: 'Some user name'}),
+      'Some user name'
+    );
+  });
+
+  test('getAccountDisplayName - account with email only', () => {
+    assert.equal(
+      getAccountDisplayName(config, {
+        email: 'my@example.com' as EmailAddress,
+      }),
+      'my@example.com <my@example.com>'
+    );
+  });
+
+  test('getAccountDisplayName - account with name and status', () => {
+    assert.equal(
+      getAccountDisplayName(config, {
+        name: 'Some name',
+        status: 'OOO',
+      }),
+      'Some name (OOO)'
+    );
+  });
+
+  test('getAccountDisplayName - account with name and email', () => {
+    assert.equal(
+      getAccountDisplayName(config, {
+        name: 'Some name',
+        email: 'my@example.com' as EmailAddress,
+      }),
+      'Some name <my@example.com>'
+    );
+  });
+
+  test('getAccountDisplayName - account with name, email and status', () => {
+    assert.equal(
+      getAccountDisplayName(config, {
+        name: 'Some name',
+        email: 'my@example.com' as EmailAddress,
+        status: 'OOO',
+      }),
+      'Some name <my@example.com> (OOO)'
+    );
+  });
+
+  test('getGroupDisplayName', () => {
+    assert.equal(
+      getGroupDisplayName({
+        ...createGroupInfo(),
+        name: 'Some user name' as GroupName,
+      }),
+      'Some user name (group)'
+    );
+  });
+
+  test('_accountEmail', () => {
+    assert.equal(
+      _testOnly_accountEmail('email@gerritreview.com'),
+      '<email@gerritreview.com>'
+    );
+    assert.equal(_testOnly_accountEmail(undefined), '');
+  });
+});