diff --git a/modules/testing/builder/src/jasmine-helpers.ts b/modules/testing/builder/src/jasmine-helpers.ts
index dcd11fe59002..269cbc2396ed 100644
--- a/modules/testing/builder/src/jasmine-helpers.ts
+++ b/modules/testing/builder/src/jasmine-helpers.ts
@@ -9,9 +9,16 @@
 import { BuilderHandlerFn } from '@angular-devkit/architect';
 import { json } from '@angular-devkit/core';
 import { readFileSync } from 'fs';
-import { BuilderHarness } from './builder-harness';
+import { concatMap, count, firstValueFrom, take, timeout } from 'rxjs';
+import { BuilderHarness, BuilderHarnessExecutionResult } from './builder-harness';
 import { host } from './test-utils';
 
+/**
+ * Maximum time for single build/rebuild
+ * This accounts for CI variability.
+ */
+export const BUILD_TIMEOUT = 25_000;
+
 const optionSchemaCache = new Map<string, json.schema.JsonSchema>();
 
 export function describeBuilder<T>(
@@ -45,6 +52,24 @@ export class JasmineBuilderHarness<T> extends BuilderHarness<T> {
   expectDirectory(path: string): HarnessDirectoryMatchers {
     return expectDirectory(path, this);
   }
+
+  async executeWithCases(
+    cases: ((
+      executionResult: BuilderHarnessExecutionResult,
+      index: number,
+    ) => void | Promise<void>)[],
+  ): Promise<void> {
+    const executionCount = await firstValueFrom(
+      this.execute().pipe(
+        timeout(BUILD_TIMEOUT),
+        concatMap(async (result, index) => await cases[index](result, index)),
+        take(cases.length),
+        count(),
+      ),
+    );
+
+    expect(executionCount).toBe(cases.length);
+  }
 }
 
 export interface HarnessFileMatchers {
diff --git a/packages/angular/build/src/builders/dev-server/tests/options/watch_spec.ts b/packages/angular/build/src/builders/dev-server/tests/options/watch_spec.ts
index e09ea21a58c5..9840ea2adc36 100644
--- a/packages/angular/build/src/builders/dev-server/tests/options/watch_spec.ts
+++ b/packages/angular/build/src/builders/dev-server/tests/options/watch_spec.ts
@@ -6,10 +6,10 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import { TimeoutError, concatMap, count, take, timeout } from 'rxjs';
+import { TimeoutError } from 'rxjs';
 import { executeDevServer } from '../../index';
 import { describeServeBuilder } from '../jasmine-helpers';
-import { BASE_OPTIONS, BUILD_TIMEOUT, DEV_SERVER_BUILDER_INFO } from '../setup';
+import { BASE_OPTIONS, DEV_SERVER_BUILDER_INFO } from '../setup';
 
 describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupTarget) => {
   describe('Option: "watch"', () => {
@@ -24,27 +24,21 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
       });
 
       await harness
-        .execute()
-        .pipe(
-          timeout(BUILD_TIMEOUT),
-          concatMap(async ({ result }, index) => {
+        .executeWithCases([
+          async ({ result }) => {
+            // Initial build should succeed
             expect(result?.success).toBe(true);
 
-            switch (index) {
-              case 0:
-                await harness.modifyFile(
-                  'src/main.ts',
-                  (content) => content + 'console.log("abcd1234");',
-                );
-                break;
-              case 1:
-                fail('Expected files to not be watched.');
-                break;
-            }
-          }),
-          take(2),
-        )
-        .toPromise()
+            // Modify a file to attempt to trigger file watcher
+            await harness.modifyFile(
+              'src/main.ts',
+              (content) => content + 'console.log("abcd1234");',
+            );
+          },
+          () => {
+            fail('Expected files to not be watched.');
+          },
+        ])
         .catch((error) => {
           // Timeout is expected if watching is disabled
           if (error instanceof TimeoutError) {
@@ -60,30 +54,22 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
         watch: undefined,
       });
 
-      const buildCount = await harness
-        .execute()
-        .pipe(
-          timeout(BUILD_TIMEOUT),
-          concatMap(async ({ result }, index) => {
-            expect(result?.success).toBe(true);
-
-            switch (index) {
-              case 0:
-                await harness.modifyFile(
-                  'src/main.ts',
-                  (content) => content + 'console.log("abcd1234");',
-                );
-                break;
-              case 1:
-                break;
-            }
-          }),
-          take(2),
-          count(),
-        )
-        .toPromise();
+      await harness.executeWithCases([
+        async ({ result }) => {
+          // Initial build should succeed
+          expect(result?.success).toBe(true);
 
-      expect(buildCount).toBe(2);
+          // Modify a file to trigger file watcher
+          await harness.modifyFile(
+            'src/main.ts',
+            (content) => content + 'console.log("abcd1234");',
+          );
+        },
+        async ({ result }) => {
+          // Modifying a file should trigger a successful rebuild
+          expect(result?.success).toBe(true);
+        },
+      ]);
     });
 
     it('watches for file changes when true', async () => {
@@ -92,30 +78,22 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
         watch: true,
       });
 
-      const buildCount = await harness
-        .execute()
-        .pipe(
-          timeout(BUILD_TIMEOUT),
-          concatMap(async ({ result }, index) => {
-            expect(result?.success).toBe(true);
-
-            switch (index) {
-              case 0:
-                await harness.modifyFile(
-                  'src/main.ts',
-                  (content) => content + 'console.log("abcd1234");',
-                );
-                break;
-              case 1:
-                break;
-            }
-          }),
-          take(2),
-          count(),
-        )
-        .toPromise();
+      await harness.executeWithCases([
+        async ({ result }) => {
+          // Initial build should succeed
+          expect(result?.success).toBe(true);
 
-      expect(buildCount).toBe(2);
+          // Modify a file to trigger file watcher
+          await harness.modifyFile(
+            'src/main.ts',
+            (content) => content + 'console.log("abcd1234");',
+          );
+        },
+        async ({ result }) => {
+          // Modifying a file should trigger a successful rebuild
+          expect(result?.success).toBe(true);
+        },
+      ]);
     });
   });
 });