fix: stabilize TestWatchFile on Windows

On Windows, fsnotify may deliver the write event before the file content
is fully flushed, causing ReadInConfig to read stale data. Replace the
direct equality assertion with assert.Eventually to poll for the
expected value, giving the watcher time to pick up the final content.

Author: veeceey

viper_test.go

@@ -2462,7 +2462,12 @@ func TestWatchFile(t *testing.T) {
 		wg.Wait()
 		// then the config value should have changed
 		require.NoError(t, err)
-		assert.Equal(t, "baz", v.Get("foo"))
+		// On Windows, fsnotify may deliver the event before the file write is fully
+		// flushed, causing ReadInConfig to read stale content. Poll briefly to allow
+		// a subsequent event (or re-read) to pick up the new value.
+		assert.Eventually(t, func() bool {
+			return v.Get("foo") == "baz"
+		}, 5*time.Second, 10*time.Millisecond, "expected foo to be \"baz\"")
 	})
 
 	t.Run("link to real file changed (à la Kubernetes)", func(t *testing.T) {