Fix flaky PPAPITest.FlashClipboard.

ppapi/tests/test_flash_clipboard.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/tests/test_flash_clipboard.h"
 
 #include "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
 #include "ppapi/cpp/point.h"
 #include "ppapi/tests/testing_instance.h"
@@ skipping 15 matching lines @@
   RUN_TEST(ReadWrite);
 }
 
 std::string TestFlashClipboard::TestReadWrite() {
   std::string input_str("Hello, world");
   pp::Var input_var(input_str);
   clipboard_interface_->WritePlainText(instance_->pp_instance(),
                                        PP_FLASH_CLIPBOARD_TYPE_STANDARD,
                                        input_var.pp_var());
 
-  ASSERT_TRUE(clipboard_interface_->IsFormatAvailable(
-      instance_->pp_instance(),
-      PP_FLASH_CLIPBOARD_TYPE_STANDARD,
-      PP_FLASH_CLIPBOARD_FORMAT_PLAINTEXT));
+  // WritePlainText() causes an async request sent to the browser process.
+  // As a result, the string written may not be reflected by IsFormatAvailable()
+  // or ReadPlainText() immediately. We need to wait and retry.

[Paweł Hajdan Jr., 2011/11/14 12:32:48]

I'm not sure how well this will work. If you really want to fix flakiness,
please make it wait for an event instead of sleeping in a loop.

[dmichael (off chromium), 2011/11/14 15:48:15]

Oops, he is right. I wasn't looking carefully enough. You need to use
PPB_Testing_Dev.RunMessageLoop below instead of sleeping. I'm kind of surprised
the OOP test is working.

+  const int kIntervalMs = 250;
+  const int kMaxIntervals = kActionTimeoutMs / kIntervalMs;
 
-  pp::Var result_var(pp::Var::PassRef(),
-      clipboard_interface_->ReadPlainText(instance_->pp_instance(),
-                                          PP_FLASH_CLIPBOARD_TYPE_STANDARD));
-  ASSERT_TRUE(result_var.is_string());
+  PP_Bool is_available = PP_FALSE;
+  for (int i = 0; i < kMaxIntervals; ++i) {
+    is_available = clipboard_interface_->IsFormatAvailable(
+        instance_->pp_instance(),
+        PP_FLASH_CLIPBOARD_TYPE_STANDARD,
+        PP_FLASH_CLIPBOARD_FORMAT_PLAINTEXT);
+    if (is_available)
+      break;
 
-  std::string result_str = result_var.AsString();
+    PlatformSleep(kIntervalMs);
+  }
+  ASSERT_TRUE(is_available);
+
+  std::string result_str;
+  for (int i = 0; i < kMaxIntervals; ++i) {
+    pp::Var result_var(pp::Var::PassRef(),
+        clipboard_interface_->ReadPlainText(instance_->pp_instance(),
+                                            PP_FLASH_CLIPBOARD_TYPE_STANDARD));
+    ASSERT_TRUE(result_var.is_string());
+    result_str = result_var.AsString();
+    if (result_str == input_str)
+      break;
+
+    PlatformSleep(kIntervalMs);
+  }
+
   ASSERT_TRUE(result_str == input_str);
   PASS();
 }