test(@angular-devkit/build-angular): add initial browser builder watch option tests

Author: clydin

packages/angular_devkit/build_angular/src/browser/tests/options/watch_spec.ts

@@ -0,0 +1,103 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import { concatMap, count, take, timeout } from 'rxjs/operators';
+import { buildWebpackBrowser } from '../../index';
+import { BASE_OPTIONS, BROWSER_BUILDER_INFO, describeBuilder } from '../setup';
+
+describeBuilder(buildWebpackBrowser, BROWSER_BUILDER_INFO, (harness) => {
+  describe('Option: "watch"', () => {
+    it('does not wait for file changes when false', (done) => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        watch: false,
+      });
+
+      // If the build waits then it will timeout with the custom timeout.
+      // A single build should not take more than 15 seconds.
+      let count = 0;
+      harness
+        .execute()
+        .pipe(timeout(15000))
+        .subscribe({
+          complete() {
+            expect(count).toBe(1);
+            done();
+          },
+          next({ result }) {
+            count++;
+            expect(result?.success).toBe(true);
+          },
+          error(error) {
+            done.fail(error);
+          },
+        });
+    });
+
+    it('does not wait for file changes when not present', (done) => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+      });
+
+      // If the build waits then it will timeout with the custom timeout.
+      // A single build should not take more than 15 seconds.
+      let count = 0;
+      harness
+        .execute()
+        .pipe(timeout(15000))
+        .subscribe({
+          complete() {
+            expect(count).toBe(1);
+            done();
+          },
+          next({ result }) {
+            count++;
+            expect(result?.success).toBe(true);
+          },
+          error(error) {
+            done.fail(error);
+          },
+        });
+    });
+
+    it('watches for file changes when true', async () => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+        main: 'src/main.ts',
+        watch: true,
+      });
+
+      const buildCount = await harness
+        .execute()
+        .pipe(
+          timeout(30000),
+          concatMap(async ({ result }, index) => {
+            expect(result?.success).toBe(true);
+
+            switch (index) {
+              case 0:
+                harness.expectFile('dist/main.js').content.not.toContain('abcd1234');
+
+                await harness.modifyFile(
+                  'src/main.ts',
+                  (content) => content + 'console.log("abcd1234");',
+                );
+                break;
+              case 1:
+                harness.expectFile('dist/main.js').content.toContain('abcd1234');
+                break;
+            }
+          }),
+          take(2),
+          count(),
+        )
+        .toPromise();
+
+      expect(buildCount).toBe(2);
+    });
+  });
+});