the applying flag is atomic; its test waits instead of polling

The race detector found my own new flag: Apply writes it on a worker
and Close reads it from the main loop. The test was polling a plain
field too, where the real window hears about the apply on the main
loop, which orders the writes.

1 files changed, 12 insertions, 8 deletions

diff --git a/gui/internal/model/plan_test.go b/gui/internal/model/plan_test.go
index 241a049..3b3d7b9 100644
--- a/gui/internal/model/plan_test.go
+++ b/gui/internal/model/plan_test.go
@@ -487,9 +487,10 @@ func TestCloseDuringApplyIsRefused(t *testing.T) {
 		// Hold the apply open while Close is attempted.
 		<-done
 	}
-	var applyErr error
+	finished := make(chan error, 1)
 	go func() {
-		_, applyErr = tab.Apply(context.Background())
+		_, err := tab.Apply(context.Background())
+		finished <- err
 	}()
 	<-started
 
@@ -497,12 +498,15 @@ func TestCloseDuringApplyIsRefused(t *testing.T) {
 		t.Error("Close during an apply was allowed: the lock and the log go out from under it")
 	}
 	close(done)
-	// Let the apply finish before the sandbox is torn down.
-	for i := 0; i < 200 && !tab.Applied; i++ {
-		time.Sleep(10 * time.Millisecond)
-	}
-	if applyErr != nil {
-		t.Errorf("the apply itself failed: %v", applyErr)
+	// Wait for the apply rather than polling its fields: the real window
+	// hears about it on the main loop, which orders the writes.
+	select {
+	case err := <-finished:
+		if err != nil {
+			t.Errorf("the apply itself failed: %v", err)
+		}
+	case <-time.After(30 * time.Second):
+		t.Fatal("the apply never finished")
 	}
 }