Enable coverage reporting.

This patch enables code coverage reporting during unit tests via
the `karma-coverage` plugin, and writes them in HTML form to the
`cover` directory where they can be collected as part of the test
job output.

Change-Id: Ic280664eaf5d5f85acfaeb3f54b314129e9ed786

.gitignore

@@ -2,6 +2,7 @@
 .idea
 node_modules
 build
+cover
 app/js/templates.js
 *.py[cod]
 

README.rst

@@ -118,8 +118,18 @@ To test javascript code, run::
 
     npm test
 
+This will execute both unit and end-to-end tests, and will write coverage
+reports to :code:`./cover`. To indvidually run unit tests and generate coverage
+reports, run::
+
+    npm run unit
+
+Similarly, to run only end-to-end tests, run::
+
+    npm run e2e
+
 Alternatively, you can start the karma server and have it watch for changes in
-your files so that tests are run every time they change, allowing for much
+your files so that unit tests are run every time they change, allowing for much
 faster feedback::
 
     ./node_modules/karma/bin/karma start test/karma.conf.js --no-single-run

test/karma.conf.js

@@ -23,7 +23,7 @@ module.exports = function(config) {
       'app/js/**/*.js': ['browserify', 'babel', 'coverage']
     },
 
-    reporters: ['spec'],
+    reporters: ['spec', 'coverage'],
 
     port: 9876,
 
@@ -57,6 +57,14 @@ module.exports = function(config) {
       ]
     },
 
+    coverageReporter: {
+      type: 'html',
+      dir: 'cover',
+      instrumenterOptions: {
+        istanbul: {noCompact: true}
+      }
+    },
+
     proxies: {
       '/': 'http://localhost:9876/'
     },