Implement support for transforming snapshot resolvers

e2e/__tests__/transform.test.ts

@@ -7,6 +7,7 @@
 
 import {tmpdir} from 'os';
 import * as path from 'path';
+import * as fs from 'graceful-fs';
 import {wrap} from 'jest-snapshot-serializer-raw';
 import {onNodeVersions} from '@jest/test-utils';
 import {
@@ -207,6 +208,39 @@ describe('transformer caching', () => {
   });
 });
 
+describe('transform-snapshotResolver', () => {
+  const dir = path.resolve(
+    __dirname,
+    '..',
+    'transform/transform-snapshotResolver',
+  );
+  const snapshotDir = path.resolve(dir, '__snapshots__');
+  const snapshotFile = path.resolve(snapshotDir, 'snapshot.test.js.snap');
+
+  const cleanupTest = () => {
+    if (fs.existsSync(snapshotFile)) {
+      fs.unlinkSync(snapshotFile);
+    }
+    if (fs.existsSync(snapshotDir)) {
+      fs.rmdirSync(snapshotDir);
+    }
+  };
+
+  beforeEach(cleanupTest);
+  afterAll(cleanupTest);
+
+  it('should transform the snapshotResolver', () => {
+    const result = runJest(dir, ['-w=1', '--no-cache', '--ci=false']);
+
+    expect(result.stderr).toMatch('1 snapshot written from 1 test suite');
+
+    const contents = require(snapshotFile);
+    expect(contents).toHaveProperty(
+      'snapshots are written to custom location 1',
+    );
+  });
+});
+
 describe('transform-environment', () => {
   const dir = path.resolve(__dirname, '../transform/transform-environment');
 

e2e/transform/transform-snapshotResolver/__tests__/snapshot.test.js

@@ -0,0 +1,10 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+test('snapshots are written to custom location', () => {
+  expect('foobar').toMatchSnapshot();
+});

e2e/transform/transform-snapshotResolver/babel.config.js

@@ -0,0 +1,18 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+module.exports = {
+  presets: [
+    '@babel/preset-typescript',
+    [
+      '@babel/preset-env',
+      {
+        targets: {node: 'current'},
+      },
+    ],
+  ],
+};

e2e/transform/transform-snapshotResolver/customSnapshotResolver.ts

@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {SnapshotResolver} from 'jest-snapshot';
+
+const snapshotResolver: SnapshotResolver = {
+  resolveSnapshotPath: (testPath, snapshotExtension) =>
+    testPath.replace('__tests__', '__snapshots__') + snapshotExtension,
+
+  resolveTestPath: (snapshotFilePath, snapshotExtension) =>
+    snapshotFilePath
+      .replace('__snapshots__', '__tests__')
+      .slice(0, -(snapshotExtension || '').length),
+
+  testPathForConsistencyCheck: 'foo/__tests__/bar.test.js',
+};
+
+export default snapshotResolver;

e2e/transform/transform-snapshotResolver/package.json

@@ -0,0 +1,10 @@
+{
+  "jest": {
+    "testEnvironment": "node",
+    "snapshotResolver": "<rootDir>/customSnapshotResolver.ts"
+  },
+  "dependencies": {
+    "@babel/preset-env": "^7.0.0",
+    "@babel/preset-typescript": "^7.0.0"
+  }
+}

e2e/transform/transform-snapshotResolver/tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "compilerOptions": {
+    "module": "commonjs"
+  }
+}