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

runtime/vm/unit_test.h

 // Copyright (c) 2011, 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.
 
 #ifndef RUNTIME_VM_UNIT_TEST_H_
 #define RUNTIME_VM_UNIT_TEST_H_
 
 #include "include/dart_native_api.h"
 
 #include "platform/globals.h"
 
 #include "vm/ast.h"
 #include "vm/dart.h"
+#include "vm/dart_api_state.h"
 #include "vm/globals.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/longjump.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/simulator.h"
 #include "vm/zone.h"
 
 // The UNIT_TEST_CASE macro is used for tests that do not need any
@@ skipping 508 matching lines @@
   static bool TestCompileScript(const Library& library, const Script& script);
 
   // Test the Compiler::CompileFunction functionality by checking the return
   // value to see if no parse errors were reported.
   static bool TestCompileFunction(const Function& function);
 };
 
 #define EXPECT_VALID(handle)                                                   \
   do {                                                                         \
     Dart_Handle tmp_handle = (handle);                                         \
+    if (!Api::IsValid(tmp_handle)) {                                           \
+      dart::Expect(__FILE__, __LINE__)                                         \
+          .Fail(                                                               \
+              "expected '%s' to be a valid handle but '%s' has already been "  \
+              "freed\n",                                                       \
+              #handle, #handle);                                               \
+    }                                                                          \
     if (Dart_IsError(tmp_handle)) {                                            \
       dart::Expect(__FILE__, __LINE__)                                         \
           .Fail(                                                               \
               "expected '%s' to be a valid handle but found an error "         \
               "handle:\n"                                                      \
               "    '%s'\n",                                                    \
               #handle, Dart_GetError(tmp_handle));                             \
     }                                                                          \
   } while (0)
 
@@ skipping 56 matching lines @@
   ~SetFlagScope() { *flag_ = original_value_; }
 
  private:
   T* flag_;
   T original_value_;
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_UNIT_TEST_H_