Collect & report test coverage for our browser code (#209)

karma.conf.js

@@ -48,7 +48,11 @@ module.exports = function (config) {
         // test results reporter to use
         // possible values: 'dots', 'progress'
         // available reporters: https://npmjs.org/browse/keyword/karma-reporter
-        reporters: ['progress'],
+        reporters: ['progress', 'coverage'],
+
+        coverageReporter: {
+            type: 'text'
+        },
 
         // web server port
         port: 9876,

package.json

@@ -88,6 +88,7 @@
     "jasmine-core": "^3.3.0",
     "karma": "^4.0.1",
     "karma-chrome-launcher": "^2.2.0",
+    "karma-coverage": "^1.1.2",
     "karma-jasmine": "^2.0.1",
     "puppeteer": "^1.14.0"
   }

test/build.js

@@ -4,6 +4,9 @@ const fs = require('fs-extra');
 const path = require('path');
 const { build, collectModules } = require('../build-tools');
 
+// Istanbul is provided by karma-coverage
+const { Instrumenter } = require('istanbul');
+
 if (require.main === module) {
     buildCordovaJsTestBundle(process.argv[2])
         .catch(err => {
@@ -16,10 +19,19 @@ module.exports = buildCordovaJsTestBundle;
 
 // Writes the cordova-js test build bundle to bundlePath
 function buildCordovaJsTestBundle (bundlePath) {
+    const instrumenter = new Instrumenter();
+
     return build({
         platformName: 'test',
         platformVersion: 'N/A',
-        extraModules: collectTestBuildModules()
+        extraModules: collectTestBuildModules(),
+        preprocess (f) {
+            // Do not instrument our test dummies
+            if (f.path.includes('src/legacy-exec/test/')) return f;
+
+            const contents = instrumenter.instrumentSync(f.contents, f.path);
+            return Object.assign({}, f, { contents });
+        }
     })
         .then(testBundle => fs.outputFile(bundlePath, testBundle));
 }