diff --git a/src/bundle.spec.ts b/src/bundle.spec.ts
index 73df1f8d..eca71605 100644
--- a/src/bundle.spec.ts
+++ b/src/bundle.spec.ts
@@ -7,83 +7,78 @@ import { ChangedFile } from './util/interfaces';
 describe('bundle task', () => {
 
   describe('bundle', () => {
-    it('should return the value rollup task returns', (done: Function) => {
+    it('should return the value rollup task returns', () => {
       // arrange
       spyOn(rollup, rollup.rollup.name).and.returnValue(Promise.resolve());
       const context = { bundler: Constants.BUNDLER_ROLLUP};
 
       // act
-      bundle.bundle(context).then(() => {
+      return bundle.bundle(context).then(() => {
         // assert
         expect(rollup.rollup).toHaveBeenCalled();
-        done();
       });
     });
 
-    it('should throw when rollup throws', (done: Function) => {
+    it('should throw when rollup throws', () => {
       const errorText = 'simulating an error';
       // arrange
       spyOn(rollup, rollup.rollup.name).and.returnValue(Promise.reject(new Error(errorText)));
       const context = { bundler: Constants.BUNDLER_ROLLUP};
 
       // act
-      bundle.bundle(context).then(() => {
+      return bundle.bundle(context).then(() => {
         throw new Error('Should never happen');
       }).catch(err => {
         // assert
         expect(rollup.rollup).toHaveBeenCalled();
         expect(err.message).toBe(errorText);
-        done();
       });
     });
 
-    it('should return the value webpack task returns', (done: Function) => {
+    it('should return the value webpack task returns', () => {
       // arrange
       spyOn(webpack, webpack.webpack.name).and.returnValue(Promise.resolve());
       const context = { bundler: Constants.BUNDLER_WEBPACK};
 
       // act
-      bundle.bundle(context).then(() => {
+      return bundle.bundle(context).then(() => {
         // assert
         expect(webpack.webpack).toHaveBeenCalled();
-        done();
       });
     });
 
-    it('should throw when rollup throws', (done: Function) => {
+    it('should throw when rollup throws', () => {
       const errorText = 'simulating an error';
       // arrange
       spyOn(webpack, webpack.webpack.name).and.returnValue(Promise.reject(new Error(errorText)));
       const context = { bundler: Constants.BUNDLER_WEBPACK};
 
       // act
-      bundle.bundle(context).then(() => {
+      return bundle.bundle(context).then(() => {
         throw new Error('Should never happen');
       }).catch(err => {
         // assert
         expect(webpack.webpack).toHaveBeenCalled();
         expect(err.message).toBe(errorText);
-        done();
       });
     });
   });
 
   describe('bundleUpdate', () => {
-    it('should return the value rollup returns', (done: Function) => {
+    it('should return the value rollup returns', () => {
       // arrange
       spyOn(rollup, rollup.rollupUpdate.name).and.returnValue(Promise.resolve());
       const context = { bundler: Constants.BUNDLER_ROLLUP};
       const changedFiles: ChangedFile[] = [];
 
       // act
-      bundle.bundleUpdate(changedFiles, context).then(() => {
+      return bundle.bundleUpdate(changedFiles, context).then(() => {
         // assert
         expect(rollup.rollupUpdate).toHaveBeenCalledWith(changedFiles, context);
-        done();
       });
     });
 
-    it('should throw when rollup throws', (done: Function) => {
+    it('should throw when rollup throws', () => {
       const errorText = 'simulating an error';
       // arrange
       spyOn(rollup, rollup.rollupUpdate.name).and.returnValue(Promise.reject(new Error(errorText)));
@@ -91,31 +86,29 @@ describe('bundle task', () => {
       const changedFiles: ChangedFile[] = [];
 
       // act
-      bundle.bundleUpdate(changedFiles, context).then(() => {
+      return bundle.bundleUpdate(changedFiles, context).then(() => {
         throw new Error('Should never happen');
       }).catch(err => {
         // assert
         expect(rollup.rollupUpdate).toHaveBeenCalled();
         expect(err.message).toBe(errorText);
-        done();
       });
     });
 
-    it('should return the value webpack returns', (done: Function) => {
+    it('should return the value webpack returns', () => {
       // arrange
       spyOn(webpack, webpack.webpackUpdate.name).and.returnValue(Promise.resolve());
       const context = { bundler: Constants.BUNDLER_WEBPACK};
       const changedFiles: ChangedFile[] = [];
 
       // act
-      bundle.bundleUpdate(changedFiles, context).then(() => {
+      return bundle.bundleUpdate(changedFiles, context).then(() => {
         // assert
         expect(webpack.webpackUpdate).toHaveBeenCalledWith(changedFiles, context);
-        done();
       });
     });
 
-    it('should throw when webpack throws', (done: Function) => {
+    it('should throw when webpack throws', () => {
       const errorText = 'simulating an error';
       try {
         // arrange
@@ -124,13 +117,12 @@ describe('bundle task', () => {
         const changedFiles: ChangedFile[] = [];
 
         // act
-        bundle.bundleUpdate(changedFiles, context).then(() => {
+        return bundle.bundleUpdate(changedFiles, context).then(() => {
           throw new Error('Should never happen');
         }).catch(err => {
           // assert
           expect(webpack.webpackUpdate).toHaveBeenCalled();
           expect(err.message).toBe(errorText);
-          done();
         });
 
       } catch (ex) {
diff --git a/src/webpack/loader-impl.spec.ts b/src/webpack/loader-impl.spec.ts
index 87ec82d6..33497936 100644
--- a/src/webpack/loader-impl.spec.ts
+++ b/src/webpack/loader-impl.spec.ts
@@ -107,10 +107,9 @@ describe('webpack loader', () => {
     spyOn(helpers, helpers.getContext.name).and.returnValue(mockContext);
     spyOn(mockContext.fileCache, mockContext.fileCache.get.name).and.returnValue(null);
     spyOn(mockContext.fileCache, mockContext.fileCache.set.name);
-    spyOn(helpers, helpers.readFileAsync.name).and.returnValue(Promise.reject(new Error(cantReadFileError)));
-
-    // act
-    loader.webpackLoader(sourceString, mockSourceMap, mockWebpackObject);
+    spyOn(helpers, helpers.readFileAsync.name).and.callFake(() => {
+      return Promise.reject(new Error(cantReadFileError));
+    });
 
     // assert
     const assertFunction = () => {
@@ -118,6 +117,9 @@ describe('webpack loader', () => {
       expect(spy.calls.mostRecent().args[0].message).toEqual(cantReadFileError);
       done();
     };
+
+    // act
+    return loader.webpackLoader(sourceString, mockSourceMap, mockWebpackObject);
   });
 
   it('should callback with content from disk', (done: Function) => {
diff --git a/src/webpack/loader-impl.ts b/src/webpack/loader-impl.ts
index 5953616e..1223d89b 100644
--- a/src/webpack/loader-impl.ts
+++ b/src/webpack/loader-impl.ts
@@ -14,22 +14,10 @@ export function webpackLoader(source: string, map: any, webpackContex: any) {
   const javascriptPath = changeExtension(absolutePath, '.js');
   const sourceMapPath = javascriptPath + '.map';
 
-  let javascriptFile: File = null;
-  let mapFile: File = null;
-
-  const promises: Promise<File>[] = [];
-  let readJavascriptFilePromise = readFile(context.fileCache, javascriptPath);
-  promises.push(readJavascriptFilePromise);
-  readJavascriptFilePromise.then(file => {
-    javascriptFile = file;
-  });
-  let readJavascriptMapFilePromise = readFile(context.fileCache, sourceMapPath);
-  promises.push(readJavascriptMapFilePromise);
-  readJavascriptMapFilePromise.then(file => {
-    mapFile = file;
-  });
-
-  Promise.all(promises).then(() => {
+  Promise.all([
+   readFile(context.fileCache, javascriptPath),
+   readFile(context.fileCache, sourceMapPath)
+  ]).then(([javascriptFile, mapFile]) => {
     let sourceMapObject = map;
     if (mapFile) {
       try {
@@ -58,6 +46,7 @@ function readFile(fileCache: FileCache, filePath: string) {
     return Promise.resolve(file);
   }
   Logger.debug(`[Webpack] loader: File ${filePath} not found in file cache - falling back to disk`);
+
   return readFileAsync(filePath).then((fileContent: string) => {
     Logger.debug(`[Webpack] loader: Loaded ${filePath} successfully from disk`);
     const file = { path: filePath, content: fileContent };