test(plugin): add tests to prevent some regressions (#419)

test/plugin.test.js

@@ -1,32 +1,116 @@
 import { webpackPlugin } from '../src/karma-webpack';
 
+const emitterMock = {
+  on() {},
+};
+
+function initPlugin(
+  webpackOptions = {},
+  webpackServerOptions = {},
+  webpackMiddlewareOptions = {},
+  basePath = '',
+  files = [],
+  frameworks = [],
+  singleRun = true,
+  colors = true,
+  customFileHandlers = [],
+  emitter = emitterMock
+) {
+  return new webpackPlugin[1](
+    webpackOptions,
+    webpackServerOptions,
+    webpackMiddlewareOptions,
+    basePath,
+    files,
+    frameworks,
+    singleRun,
+    colors,
+    customFileHandlers,
+    emitter
+  );
+}
+
 describe('Plugin', () => {
-  describe('#make()', () => {
-    test('Defaults', (done) => {
-      const emitterMock = {
-        on() {},
-      };
+  describe('Configuration', () => {
+    it('should initialize correctly with defaults', () => {
+      initPlugin();
+    });
+
+    it('should add a default webpack entry value if not provided', () => {
+      const plugin = initPlugin({});
+
+      // this is the only place we can access the complete webpack config
+      const { options } = plugin.middleware.context.compiler;
+
+      expect(typeof options.entry).toEqual('function');
+      expect(options.entry()).toEqual({});
+    });
+
+    it('should set the output filename correctly', () => {
+      const plugin = initPlugin({});
+
+      // this is the only place we can access the complete webpack config
+      const { options } = plugin.middleware.context.compiler;
+
+      expect(options.output.filename).toEqual('[name].js');
+    });
+
+    it('should set splitChunks and runtimeChunk to false if provided', () => {
+      const plugin = initPlugin({
+        optimization: {
+          splitChunks: true,
+          runtimeChunk: true,
+        },
+      });
+
+      // this is the only place we can access the complete webpack config
+      const { options } = plugin.middleware.context.compiler;
+
+      expect(options.optimization.splitChunks).toEqual(false);
+      expect(options.optimization.runtimeChunk).toEqual(false);
+    });
+
+    it('should initialize correctly without webpackMiddleware configuration', () => {
+      initPlugin({}, null, null);
+    });
+
+    it('should allow a multi compiler webpack configuration', () => {
+      initPlugin([{}, {}]);
+    });
+  });
+
+  describe('Adding Files', () => {
+    it('should error when adding an entry to the compilation fails', (done) => {
       const compilationMock = {
         addEntry(name, dep, file, cb) {
           cb(new Error('test error'));
         },
       };
-      const Plugin = new webpackPlugin[1](
-        {},
-        {},
-        {},
-        '',
-        [],
-        [],
-        true,
-        true,
-        [],
-        emitterMock
-      );
-
-      Plugin.addFile('test.js');
-      Plugin.make(compilationMock, (err) => {
+
+      const plugin = initPlugin();
+
+      plugin.addFile('test.js');
+      plugin.make(compilationMock, (err) => {
         expect(err.message).toBe('test error');
+
+        done();
+      });
+    });
+
+    it('should store files as an entry file when added', (done) => {
+      const compilationMock = {
+        addEntry(name, dep, file, cb) {
+          cb();
+        },
+      };
+
+      const plugin = initPlugin();
+
+      plugin.addFile('test.js');
+      plugin.make(compilationMock, () => {
+        expect(plugin.entries.size).toBe(1);
+        expect(plugin.entries.get('test')).toEqual('test.js');
+
         done();
       });
     });