fix(@angular-devkit/build-angular): add a base href to karma debug context

IxquitilisSaid · alan-agius4 · commit 8b1ed419c90a · 2020-10-19T12:36:22.000+02:00
This commits adds a base href value in the karma context iframe used to run unit tests where a unit test throws: No base href set. Please provide a value for the APP_BASE_HREF token or add a base element to the document. Even if the application is fine. This is because the index.html from Angular CLI contains a base href value, but not the Karma context iframe. So when adding a unit test with a testing module that imports a NgModule, for example AppModule, which itself imports RouterModule, the unit test used to throw an error (regression appeared in router 3.1). That could be solved by either adding `RouterTestingModule` to the testing module, or by adding a provider `{ provide: APP_BASE_HREF, useValue: '/' }`, but required to understand the issue. This solves the issue in a transparent way: developers won't even encounter the problem anymore. Closes #19116 (cherry picked from commit ae94245)
diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html
@@ -9,6 +9,7 @@
 <head>
 %X_UA_COMPATIBLE%
   <title>Karma DEBUG RUNNER</title>
+  <base href="/">
   <link href="favicon.ico" rel="icon" type="image/x-icon" />
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no" />
