diff --git a/dev-packages/cloudflare-integration-tests/runner.ts b/dev-packages/cloudflare-integration-tests/runner.ts
index e7da51e8a8ed..d50422ade021 100644
--- a/dev-packages/cloudflare-integration-tests/runner.ts
+++ b/dev-packages/cloudflare-integration-tests/runner.ts
@@ -158,7 +158,14 @@ export function createRunner(...paths: string[]) {
 
       let envelopeCount = 0;
       const envelopeWaiters: { expected: Expected; resolve: () => void; reject: (e: unknown) => void }[] = [];
-      const { resolve: setWorkerPort, promise: workerPortPromise } = deferredPromise<number>();
+      const {
+        resolve: setWorkerPort,
+        reject: rejectWorkerPort,
+        promise: workerPortPromise,
+      } = deferredPromise<number>();
+      workerPortPromise.catch(() => {
+        // handled in `makeRequest`
+      });
       let child: ReturnType<typeof spawn> | undefined;
       let childSubWorker: ReturnType<typeof spawn> | undefined;
 
@@ -277,6 +284,10 @@ export function createRunner(...paths: string[]) {
                   resolve(parseInt(new URL(match[1]).port, 10));
                 }
               });
+
+              childProcess.on('close', (code, sig) => {
+                reject(new Error(`wrangler exited with code ${code} (signal ${sig}) before becoming ready`));
+              });
             });
           }
 
@@ -340,7 +351,10 @@ export function createRunner(...paths: string[]) {
 
           setWorkerPort(workerPort);
         })
-        .catch(e => reject(e));
+        .catch(e => {
+          rejectWorkerPort(e);
+          reject(e);
+        });
 
       return {
         completed: async function (): Promise<void> {
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-spans/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-spans/test.ts
index 483b170936e4..1b7becdc12e1 100644
--- a/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-spans/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject-spans/test.ts
@@ -6,8 +6,7 @@ import { createRunner } from '../../../runner';
 // must appear as children of the DO transaction. The first invocation always worked;
 // the second invocation on the same DO instance previously lost its child spans
 // because the client was disposed after the first call.
-// TODO: unskip - this test is flaky, timing out in CI
-it.skip('sends child spans on repeated Durable Object calls', async ({ signal }) => {
+it('sends child spans on repeated Durable Object calls', async ({ signal }) => {
   function assertDoWorkEnvelope(envelope: unknown): void {
     const transactionEvent = (envelope as any)[1]?.[0]?.[1];
 
diff --git a/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject/test.ts b/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject/test.ts
index afb3d96637a7..4e9e65f22118 100644
--- a/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject/test.ts
+++ b/dev-packages/cloudflare-integration-tests/suites/tracing/durableobject/test.ts
@@ -69,8 +69,7 @@ it('handles consecutive RPC calls without throwing "RPC receiver does not implem
 // the Proxy must ensure `this` refers to the original object (not the Proxy),
 // otherwise private field access throws: "Cannot read private member from an object
 // whose class did not declare it"
-// TODO: unskip - this test is flaky, timing out in CI (#21201)
-it.skip('allows RPC methods to access private class fields', async ({ signal }) => {
+it('allows RPC methods to access private class fields', async ({ signal }) => {
   const runner = createRunner(__dirname)
     .expect(envelope => {
       const transactionEvent = envelope[1]?.[0]?.[1] as Event;
diff --git a/dev-packages/cloudflare-integration-tests/vite.config.mts b/dev-packages/cloudflare-integration-tests/vite.config.mts
index 0fdb560b8f11..10b3f319b762 100644
--- a/dev-packages/cloudflare-integration-tests/vite.config.mts
+++ b/dev-packages/cloudflare-integration-tests/vite.config.mts
@@ -10,7 +10,7 @@ export default defineConfig({
     },
     isolate: false,
     include: ['./suites/**/test.ts'],
-    testTimeout: 20_000,
+    testTimeout: 30_000,
     // Ensure we can see debug output when DEBUG=true
     ...(process.env.DEBUG
       ? {