Add tests for saveInlineSnapshots()

packages/jest-snapshot/src/__mocks__/prettier.js

@@ -0,0 +1,18 @@
+const prettier = require.requireActual('prettier');
+
+module.exports = {
+  format: (text, opts) =>
+    prettier.format(
+      text,
+      Object.assign(
+        {
+          pluginSearchDirs: [
+            require('path').dirname(require.resolve('prettier')),
+          ],
+        },
+        opts,
+      ),
+    ),
+  getFileInfo: {sync: () => ({inferredParser: 'babylon'})},
+  resolveConfig: {sync: () => null},
+};

packages/jest-snapshot/src/__tests__/utils.test.js

@@ -6,6 +6,7 @@
  */
 
 jest.mock('fs');
+jest.mock('prettier');
 
 const fs = require('fs');
 const path = require('path');
@@ -14,6 +15,7 @@ const chalk = require('chalk');
 const {
   getSnapshotData,
   getSnapshotPath,
+  saveInlineSnapshots,
   keyToTestName,
   saveSnapshotFile,
   serialize,
@@ -26,15 +28,23 @@ const {
 const writeFileSync = fs.writeFileSync;
 const readFileSync = fs.readFileSync;
 const existsSync = fs.existsSync;
+const statSync = fs.statSync;
+const readdirSync = fs.readdirSync;
 beforeEach(() => {
   fs.writeFileSync = jest.fn();
   fs.readFileSync = jest.fn();
   fs.existsSync = jest.fn(() => true);
+  fs.statSync = jest.fn(filePath => ({
+    isDirectory: () => !filePath.endsWith('.js'),
+  }));
+  fs.readdirSync = jest.fn(() => []);
 });
 afterEach(() => {
   fs.writeFileSync = writeFileSync;
   fs.readFileSync = readFileSync;
   fs.existsSync = existsSync;
+  fs.statSync = statSync;
+  fs.readdirSync = readdirSync;
 });
 
 test('keyToTestName()', () => {
@@ -84,6 +94,88 @@ test('saveSnapshotFile() works with \r', () => {
   );
 });
 
+test('saveInlineSnapshots() replaces empty function call with a template literal', () => {
+  const filename = path.join(__dirname, 'my.test.js');
+  fs.readFileSync = jest.fn(() => `expect(1).toMatchInlineSnapshot();\n`);
+
+  saveInlineSnapshots([
+    {
+      frame: {column: 11, file: filename, line: 1},
+      snapshot: `1`,
+    },
+  ]);
+
+  expect(fs.writeFileSync).toHaveBeenCalledWith(
+    filename,
+    'expect(1).toMatchInlineSnapshot(`1`);\n',
+  );
+});
+
+test('saveInlineSnapshots() replaces existing template literal', () => {
+  const filename = path.join(__dirname, 'my.test.js');
+  fs.readFileSync = jest.fn(() => 'expect(1).toMatchInlineSnapshot(`2`);\n');
+
+  saveInlineSnapshots([
+    {
+      frame: {column: 11, file: filename, line: 1},
+      snapshot: `1`,
+    },
+  ]);
+
+  expect(fs.writeFileSync).toHaveBeenCalledWith(
+    filename,
+    'expect(1).toMatchInlineSnapshot(`1`);\n',
+  );
+});
+
+test('saveInlineSnapshots() replaces existing template literal with property matchers', () => {
+  const filename = path.join(__dirname, 'my.test.js');
+  fs.readFileSync = jest.fn(
+    () => 'expect(1).toMatchInlineSnapshot({}, `2`);\n',
+  );
+
+  saveInlineSnapshots([
+    {
+      frame: {column: 11, file: filename, line: 1},
+      snapshot: `1`,
+    },
+  ]);
+
+  expect(fs.writeFileSync).toHaveBeenCalledWith(
+    filename,
+    'expect(1).toMatchInlineSnapshot({}, `1`);\n',
+  );
+});
+
+test('saveInlineSnapshots() throws if frame does not match', () => {
+  const filename = path.join(__dirname, 'my.test.js');
+  fs.readFileSync = jest.fn(() => 'expect(1).toMatchInlineSnapshot();\n');
+
+  const save = () =>
+    saveInlineSnapshots([
+      {
+        frame: {column: 2 /* incorrect */, file: filename, line: 1},
+        snapshot: `1`,
+      },
+    ]);
+
+  expect(save).toThrowError(/Couldn't locate all inline snapshots./);
+});
+
+test('saveInlineSnapshots() throws if multiple calls to to the same location', () => {
+  const filename = path.join(__dirname, 'my.test.js');
+  fs.readFileSync = jest.fn(() => 'expect(1).toMatchInlineSnapshot();\n');
+
+  const frame = {column: 11, file: filename, line: 1};
+
+  const save = () =>
+    saveInlineSnapshots([{frame, snapshot: `1`}, {frame, snapshot: `2`}]);
+
+  expect(save).toThrowError(
+    /Multiple inline snapshots for the same call are not supported./,
+  );
+});
+
 test('getSnapshotData() throws when no snapshot version', () => {
   const filename = path.join(__dirname, 'old-snapshot.snap');
   fs.readFileSync = jest.fn(() => 'exports[`myKey`] = `<div>\n</div>`;\n');

packages/jest-snapshot/src/utils.js

@@ -265,7 +265,7 @@ const createParser = (snapshots: InlineSnapshot[], inferredParser: string) => (
       }
       if (snapshotsForFrame.length > 1) {
         throw new Error(
-          'Jest: Multiple inline snapshots for the same call are not supported.',
+          'Jest. Multiple inline snapshots for the same call are not supported.',
         );
       }
       const snapshotIndex = args.findIndex(