diff --git a/packages/backend/test/tests/mfm.ts b/packages/backend/test/tests/mfm.ts
deleted file mode 100644
index 884f39d7f..000000000
--- a/packages/backend/test/tests/mfm.ts
+++ /dev/null
@@ -1,89 +0,0 @@
-import * as assert from 'assert';
-import * as mfm from 'mfm-js';
-
-import { toHtml } from '../../src/mfm/to-html.js';
-import { fromHtml } from '../../src/mfm/from-html.js';
-
-describe('toHtml', () => {
-	test('br', () => {
-		const input = 'foo\nbar\nbaz';
-		const output = '<p><span>foo<br>bar<br>baz</span></p>';
-		assert.equal(toHtml(mfm.parse(input)), output);
-	});
-
-	test('br alt', () => {
-		const input = 'foo\r\nbar\rbaz';
-		const output = '<p><span>foo<br>bar<br>baz</span></p>';
-		assert.equal(toHtml(mfm.parse(input)), output);
-	});
-});
-
-describe('fromHtml', () => {
-	test('p', () => {
-		assert.deepStrictEqual(fromHtml('<p>a</p><p>b</p>'), 'a\n\nb');
-	});
-
-	test('block element', () => {
-		assert.deepStrictEqual(fromHtml('<div>a</div><div>b</div>'), 'a\nb');
-	});
-
-	test('inline element', () => {
-		assert.deepStrictEqual(fromHtml('<ul><li>a</li><li>b</li></ul>'), 'a\nb');
-	});
-
-	test('block code', () => {
-		assert.deepStrictEqual(fromHtml('<pre><code>a\nb</code></pre>'), '```\na\nb\n```');
-	});
-
-	test('inline code', () => {
-		assert.deepStrictEqual(fromHtml('<code>a</code>'), '`a`');
-	});
-
-	test('quote', () => {
-		assert.deepStrictEqual(fromHtml('<blockquote>a\nb</blockquote>'), '> a\n> b');
-	});
-
-	test('br', () => {
-		assert.deepStrictEqual(fromHtml('<p>abc<br><br/>d</p>'), 'abc\n\nd');
-	});
-
-	test('link with different text', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/b">c</a> d</p>'), 'a [c](https://example.com/b) d');
-	});
-
-	test('link with different text, but not encoded', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/ä">c</a> d</p>'), 'a [c](<https://example.com/ä>) d');
-	});
-
-	test('link with same text', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/b">https://example.com/b</a> d</p>'), 'a https://example.com/b d');
-	});
-
-	test('link with same text, but not encoded', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/ä">https://example.com/ä</a> d</p>'), 'a <https://example.com/ä> d');
-	});
-
-	test('link with no url', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="b">c</a> d</p>'), 'a [c](b) d');
-	});
-
-	test('link without href', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a>c</a> d</p>'), 'a c d');
-	});
-
-	test('link without text', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/b"></a> d</p>'), 'a https://example.com/b d');
-	});
-
-	test('link without both', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a></a> d</p>'), 'a  d');
-	});
-
-	test('mention', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/@user" class="u-url mention">@user</a> d</p>'), 'a @user@example.com d');
-	});
-
-	test('hashtag', () => {
-		assert.deepStrictEqual(fromHtml('<p>a <a href="https://example.com/tags/a">#a</a> d</p>', ['#a']), 'a #a d');
-	});
-});
diff --git a/packages/backend/test/tests/reaction-lib.ts b/packages/backend/test/tests/reaction-lib.ts
deleted file mode 100644
index 2e767f769..000000000
--- a/packages/backend/test/tests/reaction-lib.ts
+++ /dev/null
@@ -1,83 +0,0 @@
-/*
-import * as assert from 'assert';
-
-import { toDbReaction } from '../src/misc/reaction-lib.js';
-
-describe('toDbReaction', async () => {
-	test('既存の文字列リアクションはそのまま', async () => {
-		assert.strictEqual(await toDbReaction('like'), 'like');
-	});
-
-	test('Unicodeプリンは寿司化不能とするため文字列化しない', async () => {
-		assert.strictEqual(await toDbReaction('🍮'), '🍮');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する like', async () => {
-		assert.strictEqual(await toDbReaction('👍'), 'like');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する love', async () => {
-		assert.strictEqual(await toDbReaction('❤️'), 'love');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する love 異体字セレクタなし', async () => {
-		assert.strictEqual(await toDbReaction('❤'), 'love');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する laugh', async () => {
-		assert.strictEqual(await toDbReaction('😆'), 'laugh');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する hmm', async () => {
-		assert.strictEqual(await toDbReaction('🤔'), 'hmm');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する surprise', async () => {
-		assert.strictEqual(await toDbReaction('😮'), 'surprise');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する congrats', async () => {
-		assert.strictEqual(await toDbReaction('🎉'), 'congrats');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する angry', async () => {
-		assert.strictEqual(await toDbReaction('💢'), 'angry');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する confused', async () => {
-		assert.strictEqual(await toDbReaction('😥'), 'confused');
-	});
-
-	test('プリン以外の既存のリアクションは文字列化する rip', async () => {
-		assert.strictEqual(await toDbReaction('😇'), 'rip');
-	});
-
-	test('それ以外はUnicodeのまま', async () => {
-		assert.strictEqual(await toDbReaction('🍅'), '🍅');
-	});
-
-	test('異体字セレクタ除去', async () => {
-		assert.strictEqual(await toDbReaction('㊗️'), '㊗');
-	});
-
-	test('異体字セレクタ除去 必要なし', async () => {
-		assert.strictEqual(await toDbReaction('㊗'), '㊗');
-	});
-
-	test('fallback - undefined', async () => {
-		assert.strictEqual(await toDbReaction(undefined), 'like');
-	});
-
-	test('fallback - null', async () => {
-		assert.strictEqual(await toDbReaction(null), 'like');
-	});
-
-	test('fallback - empty', async () => {
-		assert.strictEqual(await toDbReaction(''), 'like');
-	});
-
-	test('fallback - unknown', async () => {
-		assert.strictEqual(await toDbReaction('unknown'), 'like');
-	});
-});
-*/
diff --git a/packages/backend/test/tests/extract-mentions.ts b/packages/backend/test/unit/extract-mentions.ts
similarity index 81%
rename from packages/backend/test/tests/extract-mentions.ts
rename to packages/backend/test/unit/extract-mentions.ts
index e81d04c2d..66d32be1c 100644
--- a/packages/backend/test/tests/extract-mentions.ts
+++ b/packages/backend/test/unit/extract-mentions.ts
@@ -1,11 +1,11 @@
 import * as assert from 'assert';
 
 import { parse } from 'mfm-js';
-import { extractMentions } from '../../src/misc/extract-mentions.js';
+import { extractMentions } from '@/misc/extract-mentions.js';
 
 describe('Extract mentions', () => {
 	test('simple', () => {
-		const ast = parse('@foo @bar @baz')!;
+		const ast = parse('@foo @bar @baz');
 		const mentions = extractMentions(ast);
 		assert.deepStrictEqual(mentions, [{
 			username: 'foo',
@@ -23,7 +23,7 @@ describe('Extract mentions', () => {
 	});
 
 	test('nested', () => {
-		const ast = parse('@foo **@bar** @baz')!;
+		const ast = parse('@foo **@bar** @baz');
 		const mentions = extractMentions(ast);
 		assert.deepStrictEqual(mentions, [{
 			username: 'foo',
diff --git a/packages/backend/test/unit/mfm.ts b/packages/backend/test/unit/mfm.ts
new file mode 100644
index 000000000..d7ef14dfa
--- /dev/null
+++ b/packages/backend/test/unit/mfm.ts
@@ -0,0 +1,109 @@
+import * as assert from 'assert';
+import * as mfm from 'mfm-js';
+import { Test } from '@nestjs/testing';
+
+import { CoreModule } from '@/core/CoreModule.js';
+import { MfmService } from '@/core/MfmService.js';
+import { GlobalModule } from '@/GlobalModule.js';
+
+describe('toHtml', () => {
+	let mfmService: MfmService;
+
+	beforeEach(async () => {
+		const app = await Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		}).compile();
+		mfmService = app.get<MfmService>(MfmService);
+	});
+
+	test('br', () => {
+		const input = 'foo\nbar\nbaz';
+		const output = '<p><span>foo<br>bar<br>baz</span></p>';
+		assert.equal(mfmService.toHtml(mfm.parse(input)), output);
+	});
+
+	test('br alt', () => {
+		const input = 'foo\r\nbar\rbaz';
+		const output = '<p><span>foo<br>bar<br>baz</span></p>';
+		assert.equal(mfmService.toHtml(mfm.parse(input)), output);
+	});
+});
+
+describe('fromHtml', () => {
+	let mfmService: MfmService;
+
+	beforeEach(async () => {
+		const app = await Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		}).compile();
+		mfmService = app.get<MfmService>(MfmService);
+	});
+
+	test('p', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a</p><p>b</p>'), 'a\n\nb');
+	});
+
+	test('block element', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<div>a</div><div>b</div>'), 'a\nb');
+	});
+
+	test('inline element', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<ul><li>a</li><li>b</li></ul>'), 'a\nb');
+	});
+
+	test('block code', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<pre><code>a\nb</code></pre>'), '```\na\nb\n```');
+	});
+
+	test('inline code', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<code>a</code>'), '`a`');
+	});
+
+	test('quote', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<blockquote>a\nb</blockquote>'), '> a\n> b');
+	});
+
+	test('br', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>abc<br><br/>d</p>'), 'abc\n\nd');
+	});
+
+	test('link with different text', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/b">c</a> d</p>'), 'a [c](https://example.com/b) d');
+	});
+
+	test('link with different text, but not encoded', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/ä">c</a> d</p>'), 'a [c](<https://example.com/ä>) d');
+	});
+
+	test('link with same text', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/b">https://example.com/b</a> d</p>'), 'a https://example.com/b d');
+	});
+
+	test('link with same text, but not encoded', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/ä">https://example.com/ä</a> d</p>'), 'a <https://example.com/ä> d');
+	});
+
+	test('link with no url', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="b">c</a> d</p>'), 'a [c](b) d');
+	});
+
+	test('link without href', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a>c</a> d</p>'), 'a c d');
+	});
+
+	test('link without text', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/b"></a> d</p>'), 'a https://example.com/b d');
+	});
+
+	test('link without both', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a></a> d</p>'), 'a  d');
+	});
+
+	test('mention', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/@user" class="u-url mention">@user</a> d</p>'), 'a @user@example.com d');
+	});
+
+	test('hashtag', () => {
+		assert.deepStrictEqual(mfmService.fromHtml('<p>a <a href="https://example.com/tags/a">#a</a> d</p>', ['#a']), 'a #a d');
+	});
+});
diff --git a/packages/backend/test/unit/reaction-lib.ts b/packages/backend/test/unit/reaction-lib.ts
new file mode 100644
index 000000000..ac8e143a5
--- /dev/null
+++ b/packages/backend/test/unit/reaction-lib.ts
@@ -0,0 +1,90 @@
+import * as assert from 'assert';
+import { Test } from '@nestjs/testing';
+
+import { CoreModule } from '@/core/CoreModule.js';
+import { ReactionService } from '@/core/ReactionService.js';
+import { GlobalModule } from '@/GlobalModule.js';
+
+describe('toDbReaction', () => {
+	let reactionService: ReactionService;
+
+	beforeEach(async () => {
+		const app = await Test.createTestingModule({
+			imports: [GlobalModule, CoreModule],
+		}).compile();
+		reactionService = app.get<ReactionService>(ReactionService);
+	});
+
+	test('絵文字リアクションはそのまま', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('👍'), '👍');
+		assert.strictEqual(await reactionService.toDbReaction('🍅'), '🍅');
+	});
+
+	test('既存のリアクションは絵文字化する pudding', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('pudding'), '🍮');
+	});
+
+	test('既存のリアクションは絵文字化する like', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('like'), '👍');
+	});
+
+	test('既存のリアクションは絵文字化する love', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('love'), '❤');
+	});
+
+	test('既存のリアクションは絵文字化する laugh', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('laugh'), '😆');
+	});
+
+	test('既存のリアクションは絵文字化する hmm', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('hmm'), '🤔');
+	});
+
+	test('既存のリアクションは絵文字化する surprise', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('surprise'), '😮');
+	});
+
+	test('既存のリアクションは絵文字化する congrats', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('congrats'), '🎉');
+	});
+
+	test('既存のリアクションは絵文字化する angry', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('angry'), '💢');
+	});
+
+	test('既存のリアクションは絵文字化する confused', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('confused'), '😥');
+	});
+
+	test('既存のリアクションは絵文字化する rip', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('rip'), '😇');
+	});
+
+	test('既存のリアクションは絵文字化する star', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('star'), '⭐');
+	});
+
+	test('異体字セレクタ除去', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('㊗️'), '㊗');
+	});
+
+	test('異体字セレクタ除去 必要なし', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('㊗'), '㊗');
+	});
+
+	test('fallback - undefined', async () => {
+		assert.strictEqual(await reactionService.toDbReaction(undefined), '👍');
+	});
+
+	test('fallback - null', async () => {
+		assert.strictEqual(await reactionService.toDbReaction(null), '👍');
+	});
+
+	test('fallback - empty', async () => {
+		assert.strictEqual(await reactionService.toDbReaction(''), '👍');
+	});
+
+	test('fallback - unknown', async () => {
+		assert.strictEqual(await reactionService.toDbReaction('unknown'), '👍');
+	});
+});