[FEATURE] Add iframe coverage support (#194)

Adds helper module to modify the karma config such that coverage reporting works within iframes.

Co-authored-by: Tobias Sorn <tobias.sorn@sap.com>

README.md

@@ -5,22 +5,25 @@
 **Table of Contents**
 - [About](#about)
 - [Quickstart](#quickstart)
-  - [Installation](#installation)
-  - [Configuration](#configuration)
-  - [Execution](#execution)
-- [Karma configuration requirements](#karma-configuration-requirements)
+	- [Installation](#installation)
+	- [Configuration](#configuration)
+	- [Execution](#execution)
+- [Karma Configuration Requirements](#karma-configuration-requirements)
 - [Options](#options)
-  - [url](#url)
-  - [type](#type)
-  - [paths](#paths)
-  - [configPath](#configPath)
-  - [mode](#mode)
-    - [html](#html)
-    - [script](#script)
-  - [testpage](#testpage)
-  - [urlParameters](#urlParameters)
-  - [config](#config)
-  - [tests](#tests)
+	- [url](#url)
+	- [type](#type)
+	- [paths](#paths)
+	- [configPath](#configpath)
+	- [mode](#mode)
+		- [html](#html)
+		- [script](#script)
+	- [testpage](#testpage)
+	- [urlParameters](#urlparameters)
+	- [config](#config)
+	- [tests](#tests)
+- [API](#api)
+	- [helper](#helper)
+		- [configureIframeCoverage](#configureiframecoverage)
 - [License](#license)
 
 
@@ -323,6 +326,31 @@ ui5: {
 }
 ```
 
+## API
+
+### helper
+
+This plugin also comes with a helper module to be used in your Karma configuration file.
+
+#### configureIframeCoverage
+
+Enables code coverage for iframes.
+Can only be used in combination with the [karma-coverage](https://github.com/karma-runner/karma-coverage) plugin (v2.0.0+).
+
+Must be called from the karma configuration function after the coverage plugin has been configured.
+The `config` object must be passed as a parameter.
+
+```js
+module.exports = function(config) {
+	config.set({
+
+		// ...
+
+	});
+	require("karma-ui5/helper").configureIframeCoverage(config);
+};
+```
+
 ## License
 (c) Copyright 2019 SAP SE or an SAP affiliate company
 

helper.js

@@ -0,0 +1,20 @@
+/**
+ * Enables coverage reporting when an iframe is used.
+ *
+ * Will set/overwrite the config option:
+ * - config.coverageReporter.instrumenterOptions.istanbul.coverageGlobalScope
+ *
+ * @param {object} config karma configuration object
+ */
+const configureIframeCoverage = (config) => {
+	// set the coverageGlobalScope
+	config.coverageReporter = config.coverageReporter || {};
+	config.coverageReporter.instrumenterOptions = config.coverageReporter.instrumenterOptions || {};
+	config.coverageReporter.instrumenterOptions.istanbul = config.coverageReporter.instrumenterOptions.istanbul || {};
+	config.coverageReporter.instrumenterOptions.istanbul.coverageGlobalScope =
+		"(function() { var g=window;while(!g.__karma__&&g!==g.parent){g=g.parent;}; return g; })();";
+};
+
+module.exports = {
+	configureIframeCoverage
+};

lib/client/browser.js

@@ -174,6 +174,8 @@ require("./discovery.js");
 							testWindow = null;
 							runTestPage(i + 1);
 						} else {
+							// Also merge coverage results from karma window
+							mergeCoverage(window.__coverage__);
 							karma.complete({
 								coverage: coverageMap ? coverageMap.toJSON() : undefined
 							});