wip! use tap.spawn() for each test

test/nyc-test.js

@@ -1,47 +1,122 @@
-/* global describe, it */
-
 var _ = require('lodash')
 var fs = require('fs')
 var NYC = require('../')
 var path = require('path')
 var rimraf = require('rimraf')
 var sinon = require('sinon')
 var spawn = require('child_process').spawn
+var tap = require('tap')
+var tapMocha = require('tap/lib/mocha')
 
 require('chai').should()
-require('tap').mochaGlobals()
-
-describe('nyc', function () {
-  var fixtures = path.resolve(__dirname, './fixtures')
 
-  describe('cwd', function () {
-    function afterEach () {
-      delete process.env.NYC_CWD
-      rimraf.sync(path.resolve(fixtures, './nyc_output'))
+// All NYC instances that need to access disk should use fixturesDir as their
+// working directory.
+var fixturesDir = path.join(__dirname, 'fixtures')
+// The instances use a .nyc_output directory within the fixturesDir. This makes
+// it easier to clean up the data.
+var tempDir = path.join(fixturesDir, '.nyc_output')
+// Track all instances created in this process, to be cleaned up when the test
+// is done.
+var instances = []
+// Wrapper to instantiate NYC, forcing the tempDirectory option.
+function instantiate (opts) {
+  opts = _.assign({ tempDirectory: tempDir }, opts)
+  var nyc = new NYC(opts)
+  instances.push(nyc)
+  return nyc
+}
+// Deletes the .nyc_output directory. Overrides writeCoverageFile() on each
+// instance in case it wants to write coverage when the process exits.
+function cleanup () {
+  instances.forEach(function (nyc) {
+    nyc.writeCoverageFile = function () {}
+  })
+  instances = []
+  rimraf.sync(tempDir)
+}
+
+// If set, NYC_TEST_SPAWN contains the index of the test that should be
+// executed. Otherwise the test runner should be initialized.
+var spawnNthTest = parseInt(process.env.NYC_TEST_SPAWN || '-1', 10)
+// Increased after every call to it() below, allows for the current test to be
+// executed when in a tap.spawn() process.
+var testCounter = 0
+// Keep track of the nested tests. Deepest nested test is first.
+var stack = [tap.current()]
+
+// describe() and it() adopted from tap's mocha interface.
+function describe (name, fn) {
+  if (spawnNthTest === -1) {
+    // Initialize the test runner.
+    var c = stack[0]
+    if (!fn) {
+      c.test(name)
+    } else {
+      c.test(name, function (tt) {
+        stack.unshift(tt)
+        fn()
+        stack.shift()
+        tt.end()
+      })
+    }
+  } else if (fn) {
+    // Execute the function in order to get to the test that needs to be executed.
+    fn()
+  }
+}
+
+function it (name, fn) {
+  if (spawnNthTest === -1) {
+    // Initialize the test runner. It'll have to run the current file through
+    // tap.spawn(), setting the NYC_TEST_SPAWN variable.
+    if (fn) {
+      stack[0].spawn(process.execPath, process.argv.slice(1), { env: { NYC_TEST_SPAWN: testCounter } }, '(in child process)')
+    } else {
+      tapMocha.it(name)
     }
+  } else if (spawnNthTest === testCounter) {
+    // Execute this test.
+    tapMocha.it(name, function (done) {
+      try {
+        if (fn.length) {
+          fn(function (err) {
+            cleanup()
+            done(err)
+          })
+        } else {
+          fn()
+          cleanup()
+          done()
+        }
+      } catch (err) {
+        cleanup()
+        done(err)
+      }
+    })
+  }
 
-    it('sets cwd to process.cwd() if no environment variable is set', function () {
-      var nyc = new NYC()
+  testCounter++
+}
 
+describe('nyc', function () {
+  describe('cwd', function () {
+    it('sets cwd to process.cwd() if no environment variable is set', function () {
+      var nyc = instantiate()
       nyc.cwd.should.eql(process.cwd())
-      afterEach()
     })
 
     it('uses NYC_CWD environment variable for cwd if it is set', function () {
-      process.env.NYC_CWD = path.resolve(__dirname, './fixtures')
-
-      var nyc = new NYC()
+      process.env.NYC_CWD = fixturesDir
 
-      nyc.cwd.should.equal(path.resolve(__dirname, './fixtures'))
-      afterEach()
+      var nyc = instantiate()
+      nyc.cwd.should.equal(fixturesDir)
     })
   })
 
   describe('config', function () {
     it("loads 'exclude' patterns from package.json", function () {
-      var nyc = new NYC({
-        cwd: path.resolve(__dirname, './fixtures')
-      })
+      var nyc = instantiate({ cwd: fixturesDir })
 
       nyc.exclude.length.should.eql(5)
     })
@@ -65,7 +140,7 @@ describe('nyc', function () {
 
   describe('shouldInstrumentFile', function () {
     it('should exclude appropriately with defaults', function () {
-      var nyc = new NYC()
+      var nyc = instantiate()
 
       // Root package contains config.exclude
       // Restore exclude to default patterns
@@ -89,9 +164,7 @@ describe('nyc', function () {
     })
 
     it('should exclude appropriately with config.exclude', function () {
-      var nyc = new NYC({
-        cwd: fixtures
-      })
+      var nyc = instantiate({ cwd: fixturesDir })
       var shouldInstrumentFile = nyc.shouldInstrumentFile.bind(nyc)
 
       // config.excludes: "blarg", "blerg"
@@ -102,9 +175,7 @@ describe('nyc', function () {
     })
 
     it('should handle example symlinked node_module', function () {
-      var nyc = new NYC({
-        cwd: fixtures
-      })
+      var nyc = instantiate({ cwd: fixturesDir })
       var shouldInstrumentFile = nyc.shouldInstrumentFile.bind(nyc)
 
       var relPath = '../../nyc/node_modules/glob/glob.js'
@@ -121,7 +192,7 @@ describe('nyc', function () {
     })
 
     it('allows a file to be included rather than excluded', function () {
-      var nyc = new NYC()
+      var nyc = instantiate()
 
       // Root package contains config.exclude
       // Restore exclude to default patterns
@@ -137,10 +208,7 @@ describe('nyc', function () {
 
   describe('wrap', function () {
     it('wraps modules with coverage counters when they are required', function () {
-      var nyc = new NYC({
-        cwd: process.cwd()
-      })
-      nyc.wrap()
+      instantiate().wrap()
 
       // clear the module cache so that
       // we pull index.js in again and wrap it.
@@ -158,10 +226,7 @@ describe('nyc', function () {
           module._compile(fs.readFileSync(filename, 'utf8'))
         })
 
-        var nyc = new NYC({
-          cwd: process.cwd()
-        })
-        nyc.wrap()
+        instantiate().wrap()
 
         // clear the module cache so that
         // we pull index.js in again and wrap it.
@@ -209,9 +274,7 @@ describe('nyc', function () {
     })
 
     it('does not output coverage for files that have not been included, by default', function (done) {
-      var nyc = (new NYC({
-        cwd: process.cwd()
-      })).wrap()
+      var nyc = instantiate().wrap()
 
       var reports = _.filter(nyc._loadReports(), function (report) {
         return report['./test/fixtures/not-loaded.js']
@@ -292,8 +355,8 @@ describe('nyc', function () {
     it('handles multiple reporters', function (done) {
       var reporters = ['text-summary', 'text-lcov']
       var incr = 0
-      var nyc = new NYC({
-        cwd: process.cwd(),
+      var nyc = instantiate({
+        cwd: fixturesDir,
         reporter: reporters
       })
       var proc = spawn(process.execPath, ['./test/fixtures/sigint.js'], {
@@ -339,18 +402,14 @@ describe('nyc', function () {
 
     it('it handles having no .istanbul.yml in the root directory', function (done) {
       afterEach()
-      var nyc = new NYC()
-      nyc.wrap()
+      instantiate().wrap()
       return done()
     })
 
     it('uses the values in .istanbul.yml to instantiate the instrumenter', function (done) {
       writeConfig()
 
-      var nyc = new NYC({
-        istanbul: istanbul
-      })
-      nyc.wrap()
+      instantiate({ istanbul: istanbul }).wrap()
 
       istanbul.config.loadFile.calledWithMatch('.istanbul.yml').should.equal(true)
       istanbul.Instrumenter.calledWith({
@@ -365,11 +424,10 @@ describe('nyc', function () {
     })
 
     it('loads the .istanbul.yml configuration from NYC_CWD', function (done) {
-      var nyc = new NYC({
+      instantiate({
         istanbul: istanbul,
         cwd: './test/fixtures'
-      })
-      nyc.wrap()
+      }).wrap()
 
       istanbul.config.loadFile.calledWithMatch(path.join('test', 'fixtures', '.istanbul.yml')).should.equal(true)
       istanbul.Instrumenter.calledWith({
@@ -396,15 +454,15 @@ describe('nyc', function () {
 
       var yargv = require('yargs').argv
 
-      var munged = (new NYC()).mungeArgs(yargv)
+      var munged = instantiate().mungeArgs(yargv)
 
       munged.should.eql(['node', 'test/nyc-test.js'])
     })
   })
 
   describe('addAllFiles', function () {
     it('outputs an empty coverage report for all files that are not excluded', function (done) {
-      var nyc = (new NYC())
+      var nyc = instantiate()
       nyc.addAllFiles()
 
       var reports = _.filter(nyc._loadReports(), function (report) {
@@ -419,16 +477,16 @@ describe('nyc', function () {
     })
 
     it('tracks coverage appropriately once the file is required', function (done) {
-      var nyc = (new NYC({
-        cwd: process.cwd()
-      })).wrap()
+      var nyc = instantiate({
+        cwd: fixturesDir
+      }).wrap()
       require('./fixtures/not-loaded')
 
       nyc.writeCoverageFile()
       var reports = _.filter(nyc._loadReports(), function (report) {
-        return report['./test/fixtures/not-loaded.js']
+        return report['./not-loaded.js']
       })
-      var report = reports[0]['./test/fixtures/not-loaded.js']
+      var report = reports[0]['./not-loaded.js']
 
       reports.length.should.equal(1)
       report.s['1'].should.equal(1)