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

runtime/vm/handles_test.cc

Index: runtime/vm/handles_test.cc
diff --git a/runtime/vm/handles_test.cc b/runtime/vm/handles_test.cc
index 8a05fb750af0db59d9dc811f43dd6739a6394f46..83fc300ca454f371cc12521175600b5202b66bc3 100644
--- a/runtime/vm/handles_test.cc
+++ b/runtime/vm/handles_test.cc
@@ -3,6 +3,7 @@
 // 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"
@@ -77,4 +78,19 @@ TEST_CASE(AllocateScopeHandle) {
   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