diff --git a/package.json b/package.json
index 3bbd8ce..3aa6ecd 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
     "lint:staged": "nice-move lint staged",
     "prepare": "git config core.hooksPath .githooks",
     "prepublishOnly": "npm run lint:staged && npm test",
+    "snapshot": "ava --fail-fast -u -w",
     "test": "ava --fail-fast"
   },
   "dependencies": {
diff --git a/test/snapshots/test.mjs.md b/test/snapshots/test.mjs.md
new file mode 100644
index 0000000..ef05d50
--- /dev/null
+++ b/test/snapshots/test.mjs.md
@@ -0,0 +1,120 @@
+# Snapshot report for `test/test.mjs`
+
+The actual snapshot is saved in `test.mjs.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## preprocess
+
+> Snapshot 1
+
+    {
+      filename: 'fake.htm/0/html-script-module.js',
+      text: `␊
+                                ␊
+            'use strict';␊
+          `,
+    }
+
+> Snapshot 2
+
+    {
+      filename: 'fake.htm/1/html-script-legacy.js',
+      text: `␊
+                                ␊
+                         ␊
+                   ␊
+                  ␊
+            alert();␊
+          `,
+    }
+
+## module
+
+> Snapshot 1
+
+    {
+      errorCount: 0,
+      fatalErrorCount: 0,
+      filePath: 'D:\\open\\eslint-plugin-html\\fake.html',
+      fixableErrorCount: 0,
+      fixableWarningCount: 1,
+      messages: [
+        {
+          column: 7,
+          endColumn: 20,
+          endLine: 3,
+          fix: {
+            range: [
+              34,
+              47,
+            ],
+            text: '',
+          },
+          line: 3,
+          message: '\'use strict\' is unnecessary inside of modules.',
+          messageId: 'module',
+          nodeType: 'ExpressionStatement',
+          ruleId: 'strict',
+          severity: 1,
+        },
+      ],
+      source: `␊
+          <script type="module">␊
+            'use strict';␊
+          </script>␊
+        `,
+      suppressedMessages: [],
+      usedDeprecatedRules: [],
+      warningCount: 1,
+    }
+
+## legacy
+
+> Snapshot 1
+
+    {
+      errorCount: 0,
+      fatalErrorCount: 0,
+      filePath: 'D:\\open\\eslint-plugin-html\\fake.htm',
+      fixableErrorCount: 0,
+      fixableWarningCount: 0,
+      messages: [
+        {
+          column: 7,
+          endColumn: 15,
+          endLine: 3,
+          line: 3,
+          message: 'Use the global form of \'use strict\'.',
+          messageId: 'global',
+          nodeType: 'Program',
+          ruleId: 'strict',
+          severity: 1,
+        },
+      ],
+      source: `␊
+          <script>␊
+            alert();␊
+          </script>␊
+        `,
+      suppressedMessages: [],
+      usedDeprecatedRules: [],
+      warningCount: 1,
+    }
+
+## fix
+
+> Snapshot 1
+
+    `␊
+        <script>␊
+          'use strict';␊
+    ␊
+          alert();␊
+        </script>␊
+        abc␊
+      `
+
+> Snapshot 2
+
+    []
diff --git a/test/snapshots/test.mjs.snap b/test/snapshots/test.mjs.snap
new file mode 100644
index 0000000..71cf0a2
Binary files /dev/null and b/test/snapshots/test.mjs.snap differ
diff --git a/test/test.mjs b/test/test.mjs
index 843c3b9..8f284d0 100644
--- a/test/test.mjs
+++ b/test/test.mjs
@@ -20,14 +20,8 @@ test('preprocess', (t) => {
 
   const [first, second] = processor.preprocess(code, 'fake.htm');
 
-  t.deepEqual(first, {
-    filename: 'fake.htm/0/html-script-module.js',
-    text: "\n                          \n      'use strict';\n    ",
-  });
-  t.deepEqual(second, {
-    filename: 'fake.htm/1/html-script-legacy.js',
-    text: '\n                          \n                   \n             \n            \n      alert();\n    ',
-  });
+  t.snapshot(first);
+  t.snapshot(second);
 });
 
 test('module', async (t) => {
@@ -41,14 +35,7 @@ test('module', async (t) => {
     filePath: 'fake.html',
   });
 
-  t.true(
-    result.messages.some(
-      (message) =>
-        message.ruleId === 'strict' &&
-        message.column === 7 &&
-        message.severity === 1,
-    ),
-  );
+  t.snapshot(result);
 });
 
 test('legacy', async (t) => {
@@ -62,14 +49,7 @@ test('legacy', async (t) => {
     filePath: 'fake.htm',
   });
 
-  t.true(
-    result.messages.some(
-      (message) =>
-        message.ruleId === 'strict' &&
-        message.column === 7 &&
-        message.severity === 1,
-    ),
-  );
+  t.snapshot(result);
 });
 
 test('fix', (t) => {
@@ -81,15 +61,6 @@ test('fix', (t) => {
     abc
   `;
 
-  const expected = html`
-    <script>
-      'use strict';
-
-      alert();
-    </script>
-    abc
-  `;
-
   const messages = linter.verifyAndFix(
     code,
     {
@@ -108,6 +79,6 @@ test('fix', (t) => {
   );
 
   t.true(messages.fixed);
-  t.is(messages.output, expected);
-  t.deepEqual(messages.messages, []);
+  t.snapshot(messages.output);
+  t.snapshot(messages.messages);
 });