fix: show the assertion error first when expect.poll assertion fails (#8483)

Author: sheremet-va

packages/vitest/src/integrations/chai/poll.ts

@@ -88,12 +88,13 @@ export function createExpectPoll(expect: ExpectStatic): ExpectStatic['poll'] {
             timeoutId = setTimeout(() => {
               clearTimeout(intervalId)
               chai.util.flag(assertion, '_isLastPollAttempt', true)
-              const rejectWithCause = (cause: any) => {
+              const rejectWithCause = (error: any) => {
+                if (error.cause == null) {
+                  error.cause = new Error('Matcher did not succeed in time.')
+                }
                 reject(
                   copyStackTrace(
-                    new Error('Matcher did not succeed in time.', {
-                      cause,
-                    }),
+                    error,
                     STACK_TRACE_ERROR,
                   ),
                 )

test/core/test/expect-poll.test.ts

@@ -37,10 +37,10 @@ test('timeout', async () => {
   await expect(async () => {
     await expect.poll(() => false, { timeout: 100, interval: 10 }).toBe(true)
   }).rejects.toThrowError(expect.objectContaining({
-    message: 'Matcher did not succeed in time.',
+    message: 'expected false to be true // Object.is equality',
     stack: expect.stringContaining('expect-poll.test.ts:38:68'),
     cause: expect.objectContaining({
-      message: 'expected false to be true // Object.is equality',
+      message: 'Matcher did not succeed in time.',
     }),
   }))
 })
@@ -60,7 +60,7 @@ test('fake timers don\'t break it', async () => {
   vi.useFakeTimers()
   await expect(async () => {
     await expect.poll(() => false, { timeout: 100 }).toBe(true)
-  }).rejects.toThrowError('Matcher did not succeed in time.')
+  }).rejects.toThrowError('expected false to be true // Object.is equality')
   vi.useRealTimers()
   const diff = Date.now() - now
   expect(diff >= 100).toBe(true)
@@ -91,18 +91,18 @@ test('toBeDefined', async () => {
   await expect(() =>
     expect.poll(() => 1, { timeout: 100, interval: 10 }).not.toBeDefined(),
   ).rejects.toThrowError(expect.objectContaining({
-    message: 'Matcher did not succeed in time.',
+    message: 'expected 1 to be undefined',
     cause: expect.objectContaining({
-      message: 'expected 1 to be undefined',
+      message: 'Matcher did not succeed in time.',
     }),
   }))
 
   await expect(() =>
     expect.poll(() => undefined, { timeout: 100, interval: 10 }).toBeDefined(),
   ).rejects.toThrowError(expect.objectContaining({
-    message: 'Matcher did not succeed in time.',
+    message: 'expected undefined to be defined',
     cause: expect.objectContaining({
-      message: 'expected undefined to be defined',
+      message: 'Matcher did not succeed in time.',
     }),
   }))
 })
@@ -140,10 +140,10 @@ test('should handle failure on last attempt', async () => {
   await expect(async () => {
     await expect.poll(fn, { interval: 10, timeout: 100 }).toBe(1)
   }).rejects.toThrowError(expect.objectContaining({
-    message: 'Matcher did not succeed in time.',
+    // makes sure cause message reflects the last attempt value
+    message: 'expected 3 to be 1 // Object.is equality',
     cause: expect.objectContaining({
-      // makes sure cause message reflects the last attempt value
-      message: 'expected 3 to be 1 // Object.is equality',
+      message: 'Matcher did not succeed in time.',
     }),
   }))
 })