put tests around @shackpank's work on .istanbul.yml

Author: Benjamin Coe

README.md

@@ -74,6 +74,17 @@ adding the following configuration:
 }}
 ```
 
+## Configuring Istanbul
+
+Behind the scenes nyc uses [istanbul](https://www.npmjs.com/package/istanbul). You
+can place a `.istanbul.yml` file in your project's root directory to pass config
+setings to istanbul's code instrumenter:
+
+```yml
+instrumentation:
+  preserve-comments: true
+```
+
 ## Integrating With Coveralls
 
 [coveralls.io](https://coveralls.io) is a great tool for adding

index.js

@@ -2,14 +2,6 @@
 
 var _ = require('lodash'),
   fs = require('fs'),
-  istanbul = require('istanbul'),
-  instrumenterConfig = istanbul.config.loadFile().instrumentation.config,
-  instrumenter = new istanbul.Instrumenter({
-    coverageVariable: instrumenterConfig.variable,
-    embedSource: instrumenterConfig['embed-source'],
-    noCompact: !instrumenterConfig.compact,
-    preserveComments: instrumenterConfig['preserve-comments']
-  }),
   mkdirp = require('mkdirp'),
   path = require('path'),
   rimraf = require('rimraf'),
@@ -24,7 +16,8 @@ function NYC (opts) {
     ),
     tempDirectory: './nyc_output',
     cwd: process.env.NYC_CWD || process.cwd(),
-    reporter: 'text'
+    reporter: 'text',
+    istanbul: require('istanbul')
   }, opts)
 
   var config = require(path.resolve(this.cwd, './package.json')).config || {}
@@ -36,9 +29,26 @@ function NYC (opts) {
     return new RegExp(p)
   })
 
+  this.instrumenter = this._createInstrumenter()
+
   mkdirp.sync(this.tmpDirectory())
 }
 
+NYC.prototype._createInstrumenter = function () {
+  var configFile = path.resolve(this.cwd, './.istanbul.yml')
+
+  if (!fs.existsSync(configFile)) configFile = undefined
+
+  var instrumenterConfig = this.istanbul.config.loadFile(configFile).instrumentation.config
+
+  return new this.istanbul.Instrumenter({
+    coverageVariable: '__coverage__',
+    embedSource: instrumenterConfig['embed-source'],
+    noCompact: !instrumenterConfig.compact,
+    preserveComments: instrumenterConfig['preserve-comments']
+  })
+}
+
 NYC.prototype.cleanup = function () {
   if (!process.env.NYC_CWD) rimraf.sync(this.tmpDirectory())
 }
@@ -58,7 +68,7 @@ NYC.prototype._wrapRequire = function () {
     }
 
     if (instrument) {
-      content = instrumenter.instrumentSync(
+      content = _this.instrumenter.instrumentSync(
         content,
         './' + relFile
       )
@@ -96,8 +106,8 @@ NYC.prototype.wrap = function (bin) {
 }
 
 NYC.prototype.report = function (_collector, _reporter) {
-  var collector = _collector || new istanbul.Collector(),
-    reporter = _reporter || new istanbul.Reporter()
+  var collector = _collector || new this.istanbul.Collector(),
+    reporter = _reporter || new this.istanbul.Reporter()
 
   this._loadReports().forEach(function (report) {
     collector.add(report)

package.json

@@ -43,6 +43,7 @@
   "devDependencies": {
     "chai": "^2.3.0",
     "coveralls": "^2.11.2",
+    "sinon": "^1.14.1",
     "standard": "^3.7.3",
     "tap": "1.0.4"
   },

test/fixtures/.istanbul.yml

@@ -0,0 +1,2 @@
+instrumentation:
+  preserve-comments: true

test/nyc-test.js

@@ -5,6 +5,7 @@ var _ = require('lodash'),
   NYC = require('../'),
   path = require('path'),
   rimraf = require('rimraf'),
+  sinon = require('sinon'),
   spawn = require('child_process').spawn
 
 require('chai').should()
@@ -127,4 +128,63 @@ describe('nyc', function () {
       })
     })
   })
+
+  describe('.istanbul.yml configuration', function () {
+    var istanbul = require('istanbul')
+    var configSpy = sinon.spy(istanbul.config, 'loadFile')
+    var instrumenterSpy = sinon.spy(istanbul, 'Instrumenter')
+
+    function writeConfig () {
+      fs.writeFileSync('./.istanbul.yml', 'instrumentation:\n\tpreserve-comments: true', 'utf-8')
+    }
+
+    function afterEach () {
+      configSpy.reset()
+      instrumenterSpy.reset()
+      rimraf.sync('./.istanbul.yml')
+    }
+
+    it('it handles having no .istanbul.yml in the root directory', function (done) {
+      afterEach()
+      var nyc = new NYC()
+      return done()
+    })
+
+    it('uses the values in .istanbul.yml to instantiate the instrumenter', function (done) {
+      writeConfig()
+
+      var nyc = new NYC({
+        istanbul: istanbul
+      })
+
+      istanbul.config.loadFile.calledWithMatch('.istanbul.yml').should.equal(true)
+      istanbul.Instrumenter.calledWith({
+        coverageVariable: '__coverage__',
+        embedSource: false,
+        noCompact: false,
+        preserveComments: false
+      }).should.equal(true)
+
+      afterEach()
+      return done();
+    })
+
+    it('loads the .istanbul.yml configuration from NYC_CWD', function (done) {
+      var nyc = new NYC({
+        istanbul: istanbul,
+        cwd: './test/fixtures'
+      })
+
+      istanbul.config.loadFile.calledWithMatch('test/fixtures/.istanbul.yml').should.equal(true)
+      istanbul.Instrumenter.calledWith({
+        coverageVariable: '__coverage__',
+        embedSource: false,
+        noCompact: false,
+        preserveComments: true
+      }).should.equal(true)
+
+      afterEach()
+      return done()
+    })
+  })
 })