Quick blog as this confused me for a while. When running a unit test for a directive which had the template in an html file, I got the following error:

Error: Unexpected request: GET assets/views/template.html

Odd I thought, I haven’t been explicitly using $httpBackend. However, I discovered that when using when unit testing all HTTP requests are processed locally, and as the template is requested via HTTP, it too is processed locally.

The answer is to use karma-ng-html2js-preprocessor to generate an Angular module which puts your HTML files into a $templateCache to use in your tests. Then Angular won’t try to fetch the templates from the server.

First, install the dependency:

npm install karma-ng-html2js-preprocessor --save-dev

Then add the following to karma.conf.js (add to existing entries under files and preprocessors if they exist)

    files: [
        'build/assets/views/*.html'
    ],
    preprocessors: {
        'build/assets/views/*.html': "ng-html2js"
        },
    ngHtml2JsPreprocessor: {
        stripPrefix: 'build/',
        moduleName: 'ngTemplates' 
    }

Then in the unit test, add the line:

  beforeEach(module('ngTemplates'));

After doing this, you may encounter the following error:

Error: [$injector:modulerr] Failed to instantiate module ngTemplates due to:
Error: [$injector:nomod] Module ‘ngTemplates’ is not available! …

To get it available, you need to get the settings right – the module will only be created if html files exist in the specified directory. The stripPrefix setting allows you to ensure that the path to the view matches what is expected by you application, if the basePath in your karma.conf.js isn’t the same as the base of your application. Other settings are available too.