Added coverage support to jest preset (#76)

* Added coverage support to jest preset

* Documented jest coverage option

* Added missing documentation

docs/cli/README.md

@@ -69,6 +69,7 @@ Options:
   --presets  A list of Neutrino presets used to configure the build    [array] [default: []]
   --version  Show version number                                       [boolean]
   --help     Show help                                                 [boolean]
+  --coverage Collect test coverage information and generate report     [boolean] [default: false]
   --watch    Watch source files for changes and re-run tests           [boolean] [default: false]
 ```
 
@@ -91,6 +92,14 @@ You can also pass a flag `--watch` to watch source files for changes and re-run
 ❯ neutrino test --watch
 ```
 
+As well you can pass a flag `--coverage` to collect test coverage information and generate a report, if your preset
+supports it.
+
+```bash
+❯ neutrino test --coverage
+```
+
+
 ## Exit codes
 
 When the CLI creates an instance of Neutrino, it waits for all commands to either resolve or reject their Promise.

docs/presets/neutrino-preset-jest/README.md

@@ -8,6 +8,7 @@
 - Zero upfront configuration necessary to start testing
 - Babel compilation that compiles your tests using the same Babel options used by your source code
 - Source watching for re-running of tests on change
+- Collecting test coverage information and generating report
 - Easily extensible to customize your testing as needed
 
 ## Requirements
@@ -144,6 +145,29 @@ Use the command line [`files` parameters](/cli/README.md#neutrino-test) to execu
 `neutrino-preset-jest` can watch for changes on your source directory and subsequently re-run tests. Simply use the
 `--watch` flag with your `neutrino test` command.
 
+## Coverage reporting
+
+Jest has an integrated coverage reporter, which requires no configuration. To collect test coverage information and
+generate report run:
+
+```bash
+❯ neutrino test --coverage
+```
+
+You can also edit your package.json file and create a separate command for generating coverage report, which can be
+very helpful during continues integration of your project:
+
+```json
+{
+  "scripts": {
+    "coverage": "neutrino test --coverage"
+  }
+}
+```
+
+See the [Jest's documentation](https://facebook.github.io/jest/docs/configuration.html#collectcoveragefrom-array) for
+more configuration options for generating coverage reports.
+
 ## Customizing
 
 To override the test configuration, start with the documentation on [customization](/customization/README.md).

packages/neutrino-preset-jest/src/index.js

@@ -79,7 +79,7 @@ module.exports = neutrino => {
     const configFile = path.join(os.tmpdir(), 'config.json');
 
     return new Promise((resolve, reject) => {
-      const jestCliOptions = { config: configFile, watch: args.watch };
+      const jestCliOptions = { config: configFile, coverage: args.coverage, watch: args.watch };
 
       fs.writeFileSync(configFile, `${JSON.stringify(jest, null, 2)}\n`);
       runCLI(jestCliOptions, jest.rootDir || process.cwd(), result => {

packages/neutrino/bin/neutrino

@@ -17,6 +17,11 @@ const args = yargs
   .command('start', 'Build a project in development mode')
   .command('build', 'Compile the source directory to a bundled build')
   .command('test [files..]', 'Run all suites from the test directory or provided files', {
+    coverage: {
+      description: 'Collect test coverage information and generate report',
+      boolean: true,
+      default: false
+    },
     watch: {
       description: 'Watch source files for changes and re-run tests',
       boolean: true,