handle missing sourcemap

e2e/__tests__/v8Coverage.test.ts

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+/**
+ * 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 path from 'path';
+import runJest from '../runJest';
+
+const DIR = path.resolve(__dirname, '../v8-coverage');
+
+test('does not explode on missing sourcemap', () => {
+  const sourcemapDir = path.join(DIR, 'no-sourcemap');
+  const {stderr, status} = runJest(sourcemapDir, ['--v8-coverage'], {
+    stripAnsi: true,
+  });
+
+  expect(stderr).not.toContain('no such file or directory');
+  expect(status).toBe(0);
+});

e2e/v8-coverage/no-sourcemap/Thing.js

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+require('./x.css');
+
+module.exports = 42;

e2e/v8-coverage/no-sourcemap/__tests__/Thing.test.js

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+const Thing = require('../Thing');
+
+console.log(Thing);
+test.todo('whatever');

e2e/v8-coverage/no-sourcemap/cssTransform.js

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+module.exports = {
+  getCacheKey: () => 'cssTransform',
+  process: () => 'module.exports = {};',
+};

e2e/v8-coverage/no-sourcemap/package.json

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+{
+  "name": "no-sourcemap",
+  "version": "1.0.0",
+  "jest": {
+    "transform": {
+      "^.+\\.[jt]sx?$": "babel-jest",
+      "^.+\\.css$": "<rootDir>/cssTransform.js"
+    }
+  }
+}