fix(controller): add entropy to default dir (#469)

This adds a random number to the end of the
default karma_webpack directory. This will
prevent projects running multiple instances
of karma webpack in parallel from stepping
on one another.

Fixes #465

README.md

@@ -73,7 +73,7 @@ const defaultWebpackOptions = {
   mode: 'development',
   output: {
     filename: '[name].js',
-    path: path.join(os.tmpdir(), '_karma_webpack_'),
+    path: path.join(os.tmpdir(), '_karma_webpack_') + Math.floor(Math.random() * 1000000),
   },
   stats: {
     modules: false,

lib/KarmaWebpackController.js

@@ -36,7 +36,8 @@ const defaultWebpackOptions = {
   mode: 'development',
   output: {
     filename: '[name].js',
-    path: path.join(os.tmpdir(), '_karma_webpack_'),
+    // eslint-disable-next-line prettier/prettier
+    path: path.join(os.tmpdir(), '_karma_webpack_') + Math.floor(Math.random() * 1000000),
   },
   stats: {
     modules: false,

test/integration/scenarios/basic-setup/basic-setup.test.js

@@ -39,14 +39,14 @@ describe('A basic karma-webpack setup', () => {
     ScenarioUtils.run(config)
       .then((res) => {
         scenario = res;
-        done();
       })
-      .catch((err) => {
-        jest.fail('Karma run has failed with an error', err);
-        done();
-      });
+      .finally(() => done());
   }, KARMA_SERVER_TIMEOUT);
 
+  it('should have an exit code of 1 because it contains a failing test', () => {
+    expect(scenario.exitCode).toBe(1);
+  })
+
   it('should have three successful test runs', () => {
     expect(scenario.success).toBe(3);
   });