🐛 Fix race condition in TestWaitForErrorFirstErrSet using synctest

waiterr_test.go

@@ -3,6 +3,7 @@ package waiterr_test
 import (
 	"errors"
 	"testing"
+	"testing/synctest"
 
 	"github.com/nalgeon/be"
 
@@ -104,22 +105,21 @@ func TestWaitForErrorPanic(t *testing.T) {
 	_ = we.WaitForError()
 }
 
-func TestWaitForErrorFirstErrSet(t *testing.T) {
+func TestWaitForErrorFirstErrSet(tt *testing.T) {
 	we := new(waiterr.WaitErr)
 	expectedErr := errors.New("pre-set error")
 
-	// Manually set firstErr (requires reflection or a way to access unexported fields)
-	// For testing purposes, we can simulate this by calling Go with an error first
-	we.Go(func() error { return expectedErr })
-	we.Go(func() error { return errors.New("another error") })
-	we.Go(func() error { return nil })
+	synctest.Test(tt, func(t *testing.T) {
+		we.Go(func() error { return expectedErr })
+		// synctest.Wait ensures that the gorouting has finished before anything else.
+		synctest.Wait()
 
-	// Wait for a short period to ensure the first error is processed
-	// In a real scenario, this might be handled by a channel or more robust synchronization
-	// For this test, we'll rely on the Go routine scheduling to set firstErr quickly
-	_ = we.WaitForError() // Call once to ensure firstErr is set internally
+		we.Go(func() error { return errors.New("another error") })
+		synctest.Wait()
 
-	// Now call WaitForError again, expecting it to return the already set firstErr
-	actualErr := we.WaitForError()
-	be.Err(t, actualErr, expectedErr)
+		we.Go(func() error { return nil })
+
+		actualErr := we.WaitForError()
+		be.Err(t, actualErr, expectedErr)
+	})
 }