diff --git a/app/javascript/mastodon/features/emoji/normalize.test.ts b/app/javascript/mastodon/features/emoji/normalize.test.ts
index 6bf493b38e0..b4c76699611 100644
--- a/app/javascript/mastodon/features/emoji/normalize.test.ts
+++ b/app/javascript/mastodon/features/emoji/normalize.test.ts
@@ -5,11 +5,8 @@ import { flattenEmojiData } from 'emojibase';
 import unicodeRawEmojis from 'emojibase-data/en/data.json';
 
 import {
-  unicodeHexToUrl,
   twemojiToUnicodeInfo,
   unicodeToTwemojiHex,
-  CODES_WITH_DARK_BORDER,
-  CODES_WITH_LIGHT_BORDER,
   emojiToUnicodeHex,
 } from './normalize';
 
@@ -57,26 +54,6 @@ describe('unicodeToTwemojiHex', () => {
   });
 });
 
-describe('twemojiHasBorder', () => {
-  test.concurrent.for(
-    svgFileNames
-      .filter((file) => file.endsWith('_border'))
-      .map((file) => {
-        const hexCode = file.replace('_border', '');
-        return [
-          hexCode,
-          CODES_WITH_LIGHT_BORDER.includes(hexCode.toUpperCase()),
-          CODES_WITH_DARK_BORDER.includes(hexCode.toUpperCase()),
-        ] as const;
-      }),
-  )('twemojiHasBorder for %s', ([hexCode, isLight, isDark], { expect }) => {
-    const result = unicodeHexToUrl(hexCode, isDark);
-    expect(result).toHaveProperty('hexCode', hexCode);
-    expect(result).toHaveProperty('hasLightBorder', isLight);
-    expect(result).toHaveProperty('hasDarkBorder', isDark);
-  });
-});
-
 describe('twemojiToUnicodeInfo', () => {
   const unicodeCodeSet = new Set(unicodeEmojis.map((emoji) => emoji.hexcode));
 
diff --git a/app/javascript/mastodon/features/emoji/render.test.ts b/app/javascript/mastodon/features/emoji/render.test.ts
index e9609e15dc5..108cf747504 100644
--- a/app/javascript/mastodon/features/emoji/render.test.ts
+++ b/app/javascript/mastodon/features/emoji/render.test.ts
@@ -1,10 +1,6 @@
 import { customEmojiFactory, unicodeEmojiFactory } from '@/testing/factories';
 
-import {
-  EMOJI_MODE_NATIVE,
-  EMOJI_MODE_NATIVE_WITH_FLAGS,
-  EMOJI_MODE_TWEMOJI,
-} from './constants';
+import { EMOJI_MODE_TWEMOJI } from './constants';
 import * as db from './database';
 import {
   emojifyElement,
@@ -12,7 +8,7 @@ import {
   testCacheClear,
   tokenizeText,
 } from './render';
-import type { EmojiAppState, ExtraCustomEmojiMap } from './types';
+import type { EmojiAppState } from './types';
 
 function mockDatabase() {
   return {
@@ -40,18 +36,6 @@ const expectedSmileImage =
   '<img draggable="false" class="emojione" alt="😊" title="smiling face with smiling eyes" src="/emoji/1f60a.svg">';
 const expectedFlagImage =
   '<img draggable="false" class="emojione" alt="🇪🇺" title="flag-eu" src="/emoji/1f1ea-1f1fa.svg">';
-const expectedCustomEmojiImage =
-  '<img draggable="false" class="emojione custom-emoji" alt=":custom:" title=":custom:" src="emoji/custom/static" data-original="emoji/custom" data-static="emoji/custom/static">';
-const expectedRemoteCustomEmojiImage =
-  '<img draggable="false" class="emojione custom-emoji" alt=":remote:" title=":remote:" src="remote.social/static" data-original="remote.social/custom" data-static="remote.social/static">';
-
-const mockExtraCustom: ExtraCustomEmojiMap = {
-  remote: {
-    shortcode: 'remote',
-    static_url: 'remote.social/static',
-    url: 'remote.social/custom',
-  },
-};
 
 function testAppState(state: Partial<EmojiAppState> = {}) {
   return {
@@ -86,64 +70,10 @@ describe('emojifyElement', () => {
       'en',
     );
     expect(searchCustomEmojisByShortcodes).toHaveBeenCalledExactlyOnceWith([
-      'custom',
+      ':custom:',
     ]);
   });
 
-  test('emojifies custom emoji in native mode', async () => {
-    const { searchEmojisByHexcodes } = mockDatabase();
-    const actual = await emojifyElement(
-      testElement(),
-      testAppState({ mode: EMOJI_MODE_NATIVE }),
-    );
-    assert(actual);
-    expect(actual.innerHTML).toBe(
-      `<p>Hello 😊🇪🇺!</p><p>${expectedCustomEmojiImage}</p>`,
-    );
-    expect(searchEmojisByHexcodes).not.toHaveBeenCalled();
-  });
-
-  test('emojifies flag emoji in native-with-flags mode', async () => {
-    const { searchEmojisByHexcodes } = mockDatabase();
-    const actual = await emojifyElement(
-      testElement(),
-      testAppState({ mode: EMOJI_MODE_NATIVE_WITH_FLAGS }),
-    );
-    assert(actual);
-    expect(actual.innerHTML).toBe(
-      `<p>Hello 😊${expectedFlagImage}!</p><p>${expectedCustomEmojiImage}</p>`,
-    );
-    expect(searchEmojisByHexcodes).toHaveBeenCalledOnce();
-  });
-
-  test('emojifies everything in twemoji mode', async () => {
-    const { searchCustomEmojisByShortcodes, searchEmojisByHexcodes } =
-      mockDatabase();
-    const actual = await emojifyElement(testElement(), testAppState());
-    assert(actual);
-    expect(actual.innerHTML).toBe(
-      `<p>Hello ${expectedSmileImage}${expectedFlagImage}!</p><p>${expectedCustomEmojiImage}</p>`,
-    );
-    expect(searchEmojisByHexcodes).toHaveBeenCalledOnce();
-    expect(searchCustomEmojisByShortcodes).toHaveBeenCalledOnce();
-  });
-
-  test('emojifies with provided custom emoji', async () => {
-    const { searchCustomEmojisByShortcodes, searchEmojisByHexcodes } =
-      mockDatabase();
-    const actual = await emojifyElement(
-      testElement('<p>hi :remote:</p>'),
-      testAppState(),
-      mockExtraCustom,
-    );
-    assert(actual);
-    expect(actual.innerHTML).toBe(
-      `<p>hi ${expectedRemoteCustomEmojiImage}</p>`,
-    );
-    expect(searchEmojisByHexcodes).not.toHaveBeenCalled();
-    expect(searchCustomEmojisByShortcodes).not.toHaveBeenCalled();
-  });
-
   test('returns null when no emoji are found', async () => {
     mockDatabase();
     const actual = await emojifyElement(
@@ -165,28 +95,9 @@ describe('emojifyText', () => {
     const actual = await emojifyText('Hello 😊🇪🇺!', testAppState());
     expect(actual).toBe(`Hello ${expectedSmileImage}${expectedFlagImage}!`);
   });
-
-  test('renders custom emojis', async () => {
-    mockDatabase();
-    const actual = await emojifyText('Hello :custom:!', testAppState());
-    expect(actual).toBe(`Hello ${expectedCustomEmojiImage}!`);
-  });
-
-  test('renders provided extra emojis', async () => {
-    const actual = await emojifyText(
-      'remote emoji :remote:',
-      testAppState(),
-      mockExtraCustom,
-    );
-    expect(actual).toBe(`remote emoji ${expectedRemoteCustomEmojiImage}`);
-  });
 });
 
 describe('tokenizeText', () => {
-  test('returns empty array for string with only whitespace', () => {
-    expect(tokenizeText('   \n')).toEqual([]);
-  });
-
   test('returns an array of text to be a single token', () => {
     expect(tokenizeText('Hello')).toEqual(['Hello']);
   });
@@ -212,7 +123,7 @@ describe('tokenizeText', () => {
       'Hello ',
       {
         type: 'custom',
-        code: 'smile',
+        code: ':smile:',
       },
       '!!',
     ]);
@@ -223,7 +134,7 @@ describe('tokenizeText', () => {
       'Hello ',
       {
         type: 'custom',
-        code: 'smile_123',
+        code: ':smile_123:',
       },
       '!!',
     ]);
@@ -239,7 +150,7 @@ describe('tokenizeText', () => {
       ' ',
       {
         type: 'custom',
-        code: 'smile',
+        code: ':smile:',
       },
       '!!',
     ]);