fix: pass on error to callback for better error messages (#262)

src/karma-webpack.js

@@ -175,7 +175,7 @@ Plugin.prototype.make = function(compilation, callback) {
 
     var dep = new SingleEntryDependency(entry)
 
-    compilation.addEntry('', dep, path.relative(this.basePath, file).replace(/\\/g, '/'), function() {
+    compilation.addEntry('', dep, path.relative(this.basePath, file).replace(/\\/g, '/'), function(err) {
       // If the module fails because of an File not found error, remove the test file
       if (dep.module && dep.module.error &&
         dep.module.error.error &&
@@ -185,7 +185,7 @@ Plugin.prototype.make = function(compilation, callback) {
         })
         this.middleware.invalidate()
       }
-      callback()
+      callback(err)
     }.bind(this))
   }.bind(this), callback)
 }

test/unit/plugin.test.js

@@ -0,0 +1,24 @@
+import {assert} from 'chai'
+import {webpackPlugin} from '../../src/karma-webpack'
+
+describe('Plugin', function() {
+  describe('#make()', function() {
+    it('should pass through error from compilation', function(done) {
+      var emitterMock = {
+        on() {}
+      }
+      var compilationMock = {
+        addEntry(name, dep, file, cb) {
+          cb(new Error('test error'))
+        }
+      }
+      var Plugin = new webpackPlugin[1]({}, {}, {}, '', [], [], [], emitterMock)
+
+      Plugin.addFile('test.js')
+      Plugin.make(compilationMock, function(err) {
+        assert.equal(err.message, 'test error')
+        done()
+      })
+    })
+  })
+})