Resolution for issue #5092: Unit test handle checks consider dangling handles to be valid.

runtime/vm/handles_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/assert.h"
+#include "vm/dart_api_state.h"
 #include "vm/flags.h"
 #include "vm/handles.h"
 #include "vm/heap.h"
 #include "vm/object.h"
 #include "vm/unit_test.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 // Unit test for Zone handle allocation.
@@ skipping 54 matching lines @@
       const Smi& handle = Smi::Handle(Smi::New(i));
       EXPECT(handle.IsSmi());
       EXPECT_EQ(i, handle.Value());
     }
     EXPECT_EQ((handle_count + (2 * kNumHandles)),
               VMHandles::ScopedHandleCount());
   }
   EXPECT_EQ(handle_count, VMHandles::ScopedHandleCount());
 }
 
+
+// Unit test for handle validity checks.
+TEST_CASE(CheckHandleValidity) {
+#if defined(DEBUG)
+  FLAG_trace_handles = true;
+#endif
+  Dart_Handle handle = NULL;
+  {
+    StackZone sz(Thread::Current());
+    handle = reinterpret_cast<Dart_Handle>(&Smi::ZoneHandle(Smi::New(1)));
+    EXPECT_VALID(handle);
+  }
+  EXPECT(!Api::IsValid(handle));

[siva, 2017/01/20 17:40:03]

Can you enhance this test to also include tests for other handle types, e.g:
- create and delete a persistent handle, retain reference to the handle and
check if it is valid
- same for weak persistent handle
- start a scope and create a scoped handle, close the scope and check validity
of the handle

[bkonyi, 2017/01/20 23:07:11]

I've gone ahead and added explicit tests for scoped, persistent, and
weakpersistent handles.

+}
+
 }  // namespace dart