fix: do not dispose collectors before they are written

lib/reporter.js

@@ -59,8 +59,11 @@ var CoverageReporter = function (rootConfig, helper, logger) {
       log.error(e)
     }
 
-    if (!--pendingFileWritings) {
-      // cleanup collectors
+    --pendingFileWritings
+  }
+
+  function disposeCollectors () {
+    if (pendingFileWritings <= 0) {
       Object.keys(collectors).forEach(function (key) {
         collectors[key].dispose()
       })
@@ -154,11 +157,14 @@ var CoverageReporter = function (rootConfig, helper, logger) {
           helper.mkdirIfNotExists(outputDir, function () {
             log.debug('Writing coverage to %s', outputDir)
             writeReport(reporter, collector)
+            disposeCollectors()
           })
         }
 
       })
     })
+
+    disposeCollectors()
   }
 
   this.onExit = function (done) {

test/reporter.spec.coffee

@@ -355,3 +355,26 @@ describe 'reporter', ->
       expect(options.args[1].watermarks.branches).to.deep.equal(mockDefaultWatermarks.branches)
       expect(options.args[1].watermarks.functions).to.deep.equal(mockDefaultWatermarks.functions)
       expect(options.args[1].watermarks.lines).to.deep.equal(watermarks.lines)
+
+    it 'should not write reports after disposing the collector', ->
+      run = ->
+        reporter = new m.CoverageReporter rootConfig, mockHelper, mockLogger
+        reporter.onRunStart()
+        browsers.forEach (b) -> reporter.onBrowserStart b
+        reporter.onRunComplete browsers
+
+      rootConfig.coverageReporter.reporters = [
+        { type: 'text' }
+        { type: 'html' }
+      ]
+
+      mockDispose.reset()
+      mockWriteReport.reset()
+      mockMkdir.reset()
+
+      run()
+
+      mockMkdir.getCall(0).args[1]()
+
+      expect(mockDispose).not.to.have.been.calledBefore mockWriteReport
+