feat: find missing files when using all:true option (#208)

* add example where a file should not be covered

* find files to include using globby

* insert empty coverage for missed files

* refactor a little

* change the icon for files without any statements

* confirm file not-covered is present in the final report

* search using default extension masks if include is not present

Author: bahmutov

Diff for: .circleci/config.yml

@@ -354,6 +354,43 @@ workflows:
                   ../../node_modules/.bin/only-covered main.js
                 working_directory: examples/support-files
 
+      - cypress/run:
+          attach-workspace: true
+          name: example-all-files
+          requires:
+            - cypress/install
+          # there are no jobs to follow this one
+          # so no need to save the workspace files (saves time)
+          no-workspace: true
+          start: npm start --prefix examples/all-files
+          wait-on: 'http://localhost:1234'
+          command: npx cypress run --project examples/all-files
+          # store screenshots and videos
+          store_artifacts: true
+          post-steps:
+            - run: cat examples/all-files/.nyc_output/out.json
+            - run: cat examples/all-files/coverage/coverage-final.json
+            # store the created coverage report folder
+            # you can click on it in the CircleCI UI
+            # to see live static HTML site
+            - store_artifacts:
+                path: examples/all-files/coverage
+            # make sure the examples captures 100% of code
+            - run:
+                command: npx nyc report --check-coverage true --lines 100
+                working_directory: examples/all-files
+            - run:
+                name: Check code coverage 📈
+                # we will check the final coverage report
+                # to make sure it only has files we are interested in
+                # because there are files covered at 0 in the report
+                command: |
+                  ../../node_modules/.bin/check-coverage main.js
+                  ../../node_modules/.bin/check-coverage second.js
+                  ../../node_modules/.bin/check-coverage not-covered.js
+                  ../../node_modules/.bin/only-covered --from coverage/coverage-final.json main.js second.js not-covered.js
+                working_directory: examples/all-files
+
       - cypress/run:
           attach-workspace: true
           name: example-exclude-files
@@ -467,3 +504,4 @@ workflows:
             - example-exclude-files
             - example-docker-paths
             - example-use-webpack
+            - example-all-files

Diff for: README.md

@@ -298,6 +298,8 @@ For example, if you want to only include files in the `app` folder, but exclude
 }
 ```
 
+**Note:** if you have `all: true` NYC option set, this plugin will check the produced `.nyc_output/out.json` before generating the final report. If the `out.json` file does not have information for some files that should be there according to `include` list, then an empty placeholder will be included, see [PR 208](https://github.com/cypress-io/code-coverage/pull/208).
+
 ## Disable plugin
 
 You can skip the client-side code coverage hooks by setting the environment variable `coverage` to `false`.

Diff for: common-utils.js

@@ -0,0 +1,37 @@
+// @ts-check
+function combineNycOptions({
+  pkgNycOptions,
+  nycrc,
+  nycrcJson,
+  defaultNycOptions
+}) {
+  // last option wins
+  const nycOptions = Object.assign(
+    {},
+    defaultNycOptions,
+    nycrc,
+    nycrcJson,
+    pkgNycOptions
+  )
+
+  if (typeof nycOptions.reporter === 'string') {
+    nycOptions.reporter = [nycOptions.reporter]
+  }
+  if (typeof nycOptions.extension === 'string') {
+    nycOptions.extension = [nycOptions.extension]
+  }
+
+  return nycOptions
+}
+
+const defaultNycOptions = {
+  'report-dir': './coverage',
+  reporter: ['lcov', 'clover', 'json'],
+  extension: ['.js', '.cjs', '.mjs', '.ts', '.tsx', '.jsx'],
+  excludeAfterRemap: true
+}
+
+module.exports = {
+  combineNycOptions,
+  defaultNycOptions
+}

Diff for: cypress/integration/combine-spec.js

@@ -1,4 +1,4 @@
-const { combineNycOptions, defaultNycOptions } = require('../../task-utils')
+const { combineNycOptions, defaultNycOptions } = require('../../common-utils')
 describe('Combine NYC options', () => {
   it('overrides defaults', () => {
     const pkgNycOptions = {

Diff for: examples/all-files/.babelrc

@@ -0,0 +1,3 @@
+{
+  "plugins": ["istanbul"]
+}

Diff for: examples/all-files/README.md

@@ -0,0 +1 @@
+# example: all files

Diff for: examples/all-files/cypress.json

@@ -0,0 +1,4 @@
+{
+  "fixturesFolder": false,
+  "baseUrl": "http://localhost:1234"
+}

Diff for: examples/all-files/cypress/integration/spec.js

@@ -0,0 +1,12 @@
+/// <reference types="cypress" />
+it('works', () => {
+  cy.visit('/')
+  cy.contains('Page body')
+
+  cy.window()
+    .invoke('reverse', 'super')
+    .should('equal', 'repus')
+
+  // application's code should be instrumented
+  cy.window().should('have.property', '__coverage__')
+})

Diff for: examples/all-files/cypress/plugins/index.js

@@ -0,0 +1,5 @@
+module.exports = (on, config) => {
+  require('../../../../task')(on, config)
+  on('file:preprocessor', require('../../../../use-babelrc'))
+  return config
+}

Diff for: examples/all-files/cypress/support/commands.js

@@ -0,0 +1,2 @@
+import '../../../../support'
+console.log('this is commands file')

Diff for: examples/all-files/cypress/support/index.js

@@ -0,0 +1 @@
+require('./commands')

Diff for: examples/all-files/index.html

@@ -0,0 +1,17 @@
+<body>
+  Page body
+  <script src="main.js"></script>
+  <script src="second.js"></script>
+  <script>
+    // use functions creates in "main.js"
+    if (add(2, 3) !== 5) {
+      throw new Error('wrong addition')
+    }
+    if (sub(2, 3) !== -1) {
+      throw new Error('wrong subtraction')
+    }
+    if (reverse('foo') !== 'oof') {
+      throw new Error('wrong string reverse')
+    }
+  </script>
+</body>

Diff for: examples/all-files/main.js

@@ -0,0 +1,3 @@
+window.add = (a, b) => a + b
+
+window.sub = (a, b) => a - b

Diff for: examples/all-files/not-covered.js

@@ -0,0 +1,7 @@
+// this file is NOT included from "index.html"
+// thus it is not instrumented and not included
+// in the final code coverage numbers
+function throwsError() {
+  throw new Error('NO')
+}
+throwsError()

Diff for: examples/all-files/package.json

@@ -0,0 +1,19 @@
+{
+  "name": "example-all-files",
+  "description": "Report all files",
+  "scripts": {
+    "start": "../../node_modules/.bin/parcel serve index.html",
+    "cy:open": "../../node_modules/.bin/cypress open",
+    "cy:run": "../../node_modules/.bin/cypress run",
+    "dev": "../../node_modules/.bin/start-test 1234 cy:open",
+    "e2e": "../../node_modules/.bin/start-test 1234 cy:run",
+    "report": "../../node_modules/.bin/nyc report"
+  },
+  "nyc": {
+    "all": true,
+    "include": "*.js"
+  },
+  "devDependencies": {
+    "@babel/core": "7.9.0"
+  }
+}

Diff for: examples/all-files/second.js

@@ -0,0 +1,7 @@
+// this file should be excluded from the final coverage numbers
+// using "nyc.exclude" list in package.json
+window.reverse = s =>
+  s
+    .split('')
+    .reverse()
+    .join('')

Diff for: package-lock.json

@@ -50,8 +50,9 @@
     "@cypress/browserify-preprocessor": "2.2.1",
     "debug": "4.1.1",
     "execa": "4.0.0",
-    "nyc": "15.0.1",
-    "istanbul-lib-coverage": "3.0.0"
+    "globby": "11.0.0",
+    "istanbul-lib-coverage": "3.0.0",
+    "nyc": "15.0.1"
   },
   "devDependencies": {
     "@babel/core": "7.9.0",