feat: Create automatically fixtures output.js files for new tests (#27)

package.json

@@ -16,7 +16,9 @@
     "validate": "kcd-scripts validate",
     "precommit": "kcd-scripts precommit"
   },
-  "files": ["dist"],
+  "files": [
+    "dist"
+  ],
   "keywords": [],
   "author": "Kent C. Dodds <kent@doddsfamily.us> (http://kentcdodds.com/)",
   "license": "MIT",
@@ -45,7 +47,12 @@
       "max-lines": 0
     }
   },
-  "eslintIgnore": ["node_modules", "coverage", "dist", "fixtures"],
+  "eslintIgnore": [
+    "node_modules",
+    "coverage",
+    "dist",
+    "fixtures"
+  ],
   "babel": {
     "presets": [
       [
@@ -54,7 +61,9 @@
           "targets": {
             "node": "4.5"
           },
-          "exclude": ["transform-regenerator"]
+          "exclude": [
+            "transform-regenerator"
+          ]
         }
       ]
     ],

src/__tests__/fixtures/fixtures/without-output-file/code.js

@@ -0,0 +1 @@
+'use strict';

src/__tests__/index.js

@@ -6,7 +6,14 @@ import * as babel from 'babel-core'
 import pluginTester from '../'
 import identifierReversePlugin from './helpers/identifier-reverse-plugin'
 
-let errorSpy, describeSpy, itSpy, itOnlySpy, itSkipSpy, equalSpy, transformSpy
+let errorSpy,
+  describeSpy,
+  itSpy,
+  itOnlySpy,
+  itSkipSpy,
+  equalSpy,
+  transformSpy,
+  writeFileSyncSpy
 
 const noop = () => {}
 const titleTesterMock = (title, testFn) => testFn()
@@ -24,6 +31,9 @@ beforeEach(() => {
   itOnlySpy = global.it.only
   itSkipSpy = global.it.skip
   transformSpy = jest.spyOn(babel, 'transform')
+  writeFileSyncSpy = jest
+    .spyOn(fs, 'writeFileSync')
+    .mockImplementation(() => {})
 })
 
 afterEach(() => {
@@ -33,6 +43,7 @@ afterEach(() => {
   itSpy.mockRestore()
   itSkipSpy.mockRestore()
   transformSpy.mockRestore()
+  writeFileSyncSpy.mockRestore()
 })
 
 test('plugin is required', () => {
@@ -246,10 +257,11 @@ test('can pass tests in fixtures relative to the filename', async () => {
     }),
   )
   expect(describeSpy).toHaveBeenCalledTimes(1)
-  expect(itSpy).toHaveBeenCalledTimes(2)
+  expect(itSpy).toHaveBeenCalledTimes(3)
   expect(itSpy.mock.calls).toEqual([
     [`changed`, expect.any(Function)],
     [`unchanged`, expect.any(Function)],
+    [`without output file`, expect.any(Function)],
   ])
 })
 
@@ -267,6 +279,21 @@ test('can fail tests in fixtures at an absolute path', async () => {
   }
 })
 
+test('creates output file for new tests', async () => {
+  await pluginTester(
+    getOptions({
+      filename: __filename,
+      fixtures: 'fixtures/fixtures',
+      tests: null,
+    }),
+  )
+
+  expect(writeFileSyncSpy.mock.calls[0]).toEqual([
+    expect.stringMatching(/\/output\.js$/),
+    "'use strict';",
+  ])
+})
+
 test('uses the fixture filename in babelOptions', async () => {
   const fixture = getFixturePath('fixture1.js')
   const tests = [

src/index.js

@@ -243,8 +243,15 @@ function testFixtures({
           .transformFileSync(codePath, babelOptions)
           .code.trim()
 
+        const outputPath = path.join(fixtureDir, `${fixtureOutputName}.js`)
+
+        if (!fs.existsSync(outputPath)) {
+          fs.writeFileSync(outputPath, actual)
+          return
+        }
+
         const output = fs
-          .readFileSync(path.join(fixtureDir, `${fixtureOutputName}.js`), 'utf8')
+          .readFileSync(outputPath, 'utf8')
           .trim()
 
         assert.equal(actual, output, 'actual output does not match output.js')