feat(jest-snapshot): Support Error.cause in snapshots

dubzzz · dubzzz · commit 338be2a567a1 · 2023-02-28T14:23:41.000Z
diff --git a/e2e/__tests__/__snapshots__/toThrowErrorMatchingInlineSnapshot.test.ts.snap b/e2e/__tests__/__snapshots__/toThrowErrorMatchingInlineSnapshot.test.ts.snap
@@ -18,6 +18,37 @@ exports[`updates existing snapshot: updated snapshot 1`] = `
 "
 `;
 
+exports[`works fine when function throws error with cause: initial write with cause 1`] = `
+"test('works fine when function throws error', () => {
+  expect(() => {
+    throw new Error('apple', {
+      cause: new Error('banana', {
+        cause: new Error('orange'),
+      }),
+    });
+  }).toThrowErrorMatchingInlineSnapshot(\`
+    "apple
+    Cause: banana
+    Cause: orange"
+  \`);
+});
+"
+`;
+
+exports[`works fine when function throws error with string cause: initial write with cause 1`] = `
+"test('works fine when function throws error', () => {
+  expect(() => {
+    throw new Error('apple', {
+      cause: 'here is a cause',
+    });
+  }).toThrowErrorMatchingInlineSnapshot(\`
+    "apple
+    Cause: here is a cause"
+  \`);
+});
+"
+`;
+
 exports[`works fine when function throws error: initial write 1`] = `
 "test('works fine when function throws error', () => {
   expect(() => {
diff --git a/e2e/__tests__/toThrowErrorMatchingInlineSnapshot.test.ts b/e2e/__tests__/toThrowErrorMatchingInlineSnapshot.test.ts
@@ -43,6 +43,55 @@ test('works fine when function throws error', () => {
   }
 });
 
+test('works fine when function throws error with cause', () => {
+  const filename = 'works-fine-when-function-throws-error-with-cause.test.js';
+  const template = makeTemplate(`
+    test('works fine when function throws error', () => {
+      expect(() => {
+        throw new Error('apple', {
+          cause: new Error('banana', {
+            cause: new Error('orange')
+          })
+        });
+      })
+        .toThrowErrorMatchingInlineSnapshot();
+    });
+  `);
+
+  {
+    writeFiles(TESTS_DIR, {[filename]: template()});
+    const {stderr, exitCode} = runJest(DIR, ['-w=1', '--ci=false', filename]);
+    const fileAfter = readFile(filename);
+    expect(stderr).toMatch('1 snapshot written from 1 test suite.');
+    expect(fileAfter).toMatchSnapshot('initial write with cause');
+    expect(exitCode).toBe(0);
+  }
+});
+
+test('works fine when function throws error with string cause', () => {
+  const filename =
+    'works-fine-when-function-throws-error-with-string-cause.test.js';
+  const template = makeTemplate(`
+    test('works fine when function throws error', () => {
+      expect(() => {
+        throw new Error('apple', {
+          cause: 'here is a cause'
+        });
+      })
+        .toThrowErrorMatchingInlineSnapshot();
+    });
+  `);
+
+  {
+    writeFiles(TESTS_DIR, {[filename]: template()});
+    const {stderr, exitCode} = runJest(DIR, ['-w=1', '--ci=false', filename]);
+    const fileAfter = readFile(filename);
+    expect(stderr).toMatch('1 snapshot written from 1 test suite.');
+    expect(fileAfter).toMatchSnapshot('initial write with cause');
+    expect(exitCode).toBe(0);
+  }
+});
+
 test('updates existing snapshot', () => {
   const filename = 'updates-existing-snapshot.test.js';
   const template = makeTemplate(`
diff --git a/packages/jest-snapshot/src/index.ts b/packages/jest-snapshot/src/index.ts
@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {types} from 'util';
 import * as fs from 'graceful-fs';
 import type {Config} from '@jest/types';
 import type {MatcherFunctionWithContext} from 'expect';
@@ -522,12 +523,25 @@ const _toThrowErrorMatchingSnapshot = (
     );
   }
 
+  let message = error.message;
+  while ('cause' in error) {
+    error = error.cause;
+    if (types.isNativeError(error) || error instanceof Error) {
+      message += `\nCause: ${error.message}`;
+    } else {
+      if (typeof error === 'string') {
+        message += `\nCause: ${error}`;
+      }
+      break;
+    }
+  }
+
   return _toMatchSnapshot({
     context,
     hint,
     inlineSnapshot,
     isInline,
     matcherName,
-    received: error.message,
+    received: message,
   });
 };
