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/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
// default isolate or zone functionality.
#define UNIT_TEST_CASE(name)                                                   \
  void Dart_Test##name();                                                      \
  static const dart::TestCase kRegister##name(Dart_Test##name, #name);         \
  void Dart_Test##name()

// The VM_TEST_CASE macro is used for tests that need an isolate and zone
// in order to test its functionality. This macro is used for tests that
// are implemented using the VM code directly and do not use the Dart API
// for calling into the VM. The safepoint execution state of threads using
// this macro is transitioned from kThreadInNative to kThreadInVM.
#define VM_TEST_CASE(name)                                                     \
  static void Dart_TestHelper##name(Thread* thread);                           \
  UNIT_TEST_CASE(name) {                                                       \
    TestIsolateScope __test_isolate__;                                         \
    Thread* __thread__ = Thread::Current();                                    \
    ASSERT(__thread__->isolate() == __test_isolate__.isolate());               \
    TransitionNativeToVM transition(__thread__);                               \
    StackZone __zone__(__thread__);                                            \
    HandleScope __hs__(__thread__);                                            \
    Dart_TestHelper##name(__thread__);                                         \
  }                                                                            \
  static void Dart_TestHelper##name(Thread* thread)

// The TEST_CASE macro is used for tests that need an isolate and zone
// in order to test its functionality. This macro is used for tests that
// are implemented using the Dart API for calling into the VM. The safepoint
// execution state of threads using this macro remains kThreadNative.
#define TEST_CASE(name)                                                        \
  static void Dart_TestHelper##name(Thread* thread);                           \
  UNIT_TEST_CASE(name) {                                                       \
    TestIsolateScope __test_isolate__;                                         \
    Thread* __thread__ = Thread::Current();                                    \
    ASSERT(__thread__->isolate() == __test_isolate__.isolate());               \
    StackZone __zone__(__thread__);                                            \
    HandleScope __hs__(__thread__);                                            \
    Dart_TestHelper##name(__thread__);                                         \
  }                                                                            \
  static void Dart_TestHelper##name(Thread* thread)

// The ASSEMBLER_TEST_GENERATE macro is used to generate a unit test
// for the assembler.
#define ASSEMBLER_TEST_GENERATE(name, assembler)                               \
  void AssemblerTestGenerate##name(Assembler* assembler)

// The ASSEMBLER_TEST_EXTERN macro is used to declare a unit test
// for the assembler.
#define ASSEMBLER_TEST_EXTERN(name)                                            \
  extern void AssemblerTestGenerate##name(Assembler* assembler);

// The ASSEMBLER_TEST_RUN macro is used to execute the assembler unit
// test generated using the ASSEMBLER_TEST_GENERATE macro.
// C++ callee-saved registers are not preserved. Arguments may be passed in.
#define ASSEMBLER_TEST_RUN(name, test)                                         \
  static void AssemblerTestRun##name(AssemblerTest* test);                     \
  VM_TEST_CASE(name) {                                                         \
    Assembler __assembler__;                                                   \
    AssemblerTest test("" #name, &__assembler__);                              \
    AssemblerTestGenerate##name(test.assembler());                             \
    test.Assemble();                                                           \
    AssemblerTestRun##name(&test);                                             \
  }                                                                            \
  static void AssemblerTestRun##name(AssemblerTest* test)

// Populate node list with AST nodes.
#define CODEGEN_TEST_GENERATE(name, test)                                      \
  static void CodeGenTestGenerate##name(CodeGenTest* test)

// Populate node list with AST nodes, possibly using the provided function
// object built by a previous CODEGEN_TEST_GENERATE.
#define CODEGEN_TEST2_GENERATE(name, function, test)                           \
  static void CodeGenTestGenerate##name(const Function& function,              \
                                        CodeGenTest* test)


// Pass the name of test and the expected results as RawObject.
#define CODEGEN_TEST_RUN(name, expected)                                       \
  static void CodeGenTestRun##name(const Function& function);                  \
  VM_TEST_CASE(name) {                                                         \
    CodeGenTest __test__("" #name);                                            \
    CodeGenTestGenerate##name(&__test__);                                      \
    __test__.Compile();                                                        \
    CodeGenTestRun##name(__test__.function());                                 \
  }                                                                            \
  static void CodeGenTestRun##name(const Function& function) {                 \
    Object& result = Object::Handle();                                         \
    result = DartEntry::InvokeFunction(function, Object::empty_array());       \
    EXPECT(!result.IsError());                                                 \
    Instance& actual = Instance::Handle();                                     \
    actual ^= result.raw();                                                    \
    EXPECT(actual.CanonicalizeEquals(Instance::Handle(expected)));             \
  }


// Pass the name of test, and use the generated function to call it
// and evaluate its result.
#define CODEGEN_TEST_RAW_RUN(name, function)                                   \
  static void CodeGenTestRun##name(const Function& function);                  \
  VM_TEST_CASE(name) {                                                         \
    CodeGenTest __test__("" #name);                                            \
    CodeGenTestGenerate##name(&__test__);                                      \
    __test__.Compile();                                                        \
    CodeGenTestRun##name(__test__.function());                                 \
  }                                                                            \
  static void CodeGenTestRun##name(const Function& function)


// Generate code for two sequences of AST nodes and execute the first one.
// The first one may reference the Function object generated by the second one.
#define CODEGEN_TEST2_RUN(name1, name2, expected)                              \
  static void CodeGenTestRun##name1(const Function& function);                 \
  VM_TEST_CASE(name1) {                                                        \
    /* Generate code for name2 */                                              \
    CodeGenTest __test2__("" #name2);                                          \
    CodeGenTestGenerate##name2(&__test2__);                                    \
    __test2__.Compile();                                                       \
    /* Generate code for name1, providing function2 */                         \
    CodeGenTest __test1__("" #name1);                                          \
    CodeGenTestGenerate##name1(__test2__.function(), &__test1__);              \
    __test1__.Compile();                                                       \
    CodeGenTestRun##name1(__test1__.function());                               \
  }                                                                            \
  static void CodeGenTestRun##name1(const Function& function) {                \
    Object& result = Object::Handle();                                         \
    result = DartEntry::InvokeFunction(function, Object::empty_array());       \
    EXPECT(!result.IsError());                                                 \
    Instance& actual = Instance::Handle();                                     \
    actual ^= result.raw();                                                    \
    EXPECT(actual.CanonicalizeEquals(Instance::Handle(expected)));             \
  }


#if defined(TARGET_ARCH_ARM) || defined(TARGET_ARCH_MIPS) ||                   \
    defined(TARGET_ARCH_ARM64)
#if defined(HOST_ARCH_ARM) || defined(HOST_ARCH_MIPS) ||                       \
    defined(HOST_ARCH_ARM64)
// Running on actual ARM or MIPS hardware, execute code natively.
#define EXECUTE_TEST_CODE_INT32(name, entry) reinterpret_cast<name>(entry)()
#define EXECUTE_TEST_CODE_INT64(name, entry) reinterpret_cast<name>(entry)()
#define EXECUTE_TEST_CODE_INT64_LL(name, entry, long_arg0, long_arg1)          \
  reinterpret_cast<name>(entry)(long_arg0, long_arg1)
#define EXECUTE_TEST_CODE_FLOAT(name, entry) reinterpret_cast<name>(entry)()
#define EXECUTE_TEST_CODE_DOUBLE(name, entry) reinterpret_cast<name>(entry)()
#define EXECUTE_TEST_CODE_INT32_F(name, entry, float_arg)                      \
  reinterpret_cast<name>(entry)(float_arg)
#define EXECUTE_TEST_CODE_INT32_D(name, entry, double_arg)                     \
  reinterpret_cast<name>(entry)(double_arg)
#define EXECUTE_TEST_CODE_INTPTR_INTPTR(name, entry, pointer_arg)              \
  reinterpret_cast<name>(entry)(pointer_arg)
#define EXECUTE_TEST_CODE_INT32_INTPTR(name, entry, pointer_arg)               \
  reinterpret_cast<name>(entry)(pointer_arg)
#else
// Not running on ARM or MIPS hardware, call simulator to execute code.
#if defined(ARCH_IS_64_BIT)
#define EXECUTE_TEST_CODE_INT64(name, entry)                                   \
  static_cast<int64_t>(                                                        \
      Simulator::Current()->Call(bit_cast<int64_t, uword>(entry), 0, 0, 0, 0))
#define EXECUTE_TEST_CODE_DOUBLE(name, entry)                                  \
  bit_cast<double, int64_t>(Simulator::Current()->Call(                        \
      bit_cast<int64_t, uword>(entry), 0, 0, 0, 0, true))
#define EXECUTE_TEST_CODE_INTPTR_INTPTR(name, entry, pointer_arg)              \
  static_cast<intptr_t>(Simulator::Current()->Call(                            \
      bit_cast<int64_t, uword>(entry),                                         \
      bit_cast<int64_t, intptr_t>(pointer_arg), 0, 0, 0))
#define EXECUTE_TEST_CODE_INT32_INTPTR(name, entry, pointer_arg)               \
  static_cast<int32_t>(Simulator::Current()->Call(                             \
      bit_cast<int64_t, uword>(entry),                                         \
      bit_cast<int64_t, intptr_t>(pointer_arg), 0, 0, 0))
#else
#define EXECUTE_TEST_CODE_INT32(name, entry)                                   \
  static_cast<int32_t>(                                                        \
      Simulator::Current()->Call(bit_cast<int32_t, uword>(entry), 0, 0, 0, 0))
#define EXECUTE_TEST_CODE_DOUBLE(name, entry)                                  \
  bit_cast<double, int64_t>(Simulator::Current()->Call(                        \
      bit_cast<int32_t, uword>(entry), 0, 0, 0, 0, true))
#define EXECUTE_TEST_CODE_INTPTR_INTPTR(name, entry, pointer_arg)              \
  static_cast<intptr_t>(Simulator::Current()->Call(                            \
      bit_cast<int32_t, uword>(entry),                                         \
      bit_cast<int32_t, intptr_t>(pointer_arg), 0, 0, 0))
#define EXECUTE_TEST_CODE_INT32_INTPTR(name, entry, pointer_arg)               \
  static_cast<int32_t>(Simulator::Current()->Call(                             \
      bit_cast<int32_t, uword>(entry),                                         \
      bit_cast<int32_t, intptr_t>(pointer_arg), 0, 0, 0))
#endif  // defined(ARCH_IS_64_BIT)
#define EXECUTE_TEST_CODE_INT64_LL(name, entry, long_arg0, long_arg1)          \
  static_cast<int64_t>(Simulator::Current()->Call(                             \
      bit_cast<int32_t, uword>(entry), Utils::Low32Bits(long_arg0),            \
      Utils::High32Bits(long_arg0), Utils::Low32Bits(long_arg1),               \
      Utils::High32Bits(long_arg1)))
#define EXECUTE_TEST_CODE_FLOAT(name, entry)                                   \
  bit_cast<float, int32_t>(Simulator::Current()->Call(                         \
      bit_cast<int32_t, uword>(entry), 0, 0, 0, 0, true))
#define EXECUTE_TEST_CODE_INT32_F(name, entry, float_arg)                      \
  static_cast<int32_t>(Simulator::Current()->Call(                             \
      bit_cast<int32_t, uword>(entry), bit_cast<int32_t, float>(float_arg), 0, \
      0, 0, false, true))
#define EXECUTE_TEST_CODE_INT32_D(name, entry, double_arg)                     \
  static_cast<int32_t>(Simulator::Current()->Call(                             \
      bit_cast<int32_t, uword>(entry),                                         \
      Utils::Low32Bits(bit_cast<int64_t, double>(double_arg)),                 \
      Utils::High32Bits(bit_cast<int64_t, double>(double_arg)), 0, 0, false,   \
      true))
#endif  // defined(HOST_ARCH_ARM) || defined(HOST_ARCH_MIPS)
#endif  // defined(TARGET_ARCH_{ARM, ARM64, MIPS})


inline Dart_Handle NewString(const char* str) {
  return Dart_NewStringFromCString(str);
}


namespace dart {

// Forward declarations.
class Assembler;
class CodeGenerator;
class VirtualMemory;


namespace bin {
// vm_isolate_snapshot_buffer points to a snapshot for the vm isolate if we
// link in a snapshot otherwise it is initialized to NULL.
extern const uint8_t* vm_isolate_snapshot_buffer;

// isolate_snapshot_buffer points to a snapshot for an isolate if we link in a
// snapshot otherwise it is initialized to NULL.
extern const uint8_t* isolate_snapshot_buffer;
}


class TestCaseBase {
 public:
  explicit TestCaseBase(const char* name);
  virtual ~TestCaseBase() {}

  const char* name() const { return name_; }

  virtual void Run() = 0;
  void RunTest();

  static void RunAll();

 private:
  static TestCaseBase* first_;
  static TestCaseBase* tail_;

  TestCaseBase* next_;
  const char* name_;

  DISALLOW_COPY_AND_ASSIGN(TestCaseBase);
};

#define USER_TEST_URI "test-lib"
#define CORELIB_TEST_URI "dart:test-lib"

class TestCase : TestCaseBase {
 public:
  typedef void(RunEntry)();

  TestCase(RunEntry* run, const char* name) : TestCaseBase(name), run_(run) {}

  static Dart_Handle LoadTestScript(const char* script,
                                    Dart_NativeEntryResolver resolver,
                                    const char* lib_uri = USER_TEST_URI,
                                    bool finalize = true);
  static Dart_Handle LoadCoreTestScript(const char* script,
                                        Dart_NativeEntryResolver resolver);
  static Dart_Handle lib();
  static const char* url() { return USER_TEST_URI; }
  static Dart_Isolate CreateTestIsolateFromSnapshot(uint8_t* buffer,
                                                    const char* name = NULL) {
    return CreateIsolate(buffer, name);
  }
  static Dart_Isolate CreateTestIsolate(const char* name = NULL) {
    return CreateIsolate(bin::isolate_snapshot_buffer, name);
  }
  static Dart_Handle library_handler(Dart_LibraryTag tag,
                                     Dart_Handle library,
                                     Dart_Handle url);
  static char* BigintToHexValue(Dart_CObject* bigint);

  virtual void Run();

  // Sets |script| to be the source used at next reload.
  static void SetReloadTestScript(const char* script);
  // Initiates the reload.
  static Dart_Handle TriggerReload();
  // Gets the result of a reload.
  static Dart_Handle GetReloadErrorOrRootLibrary();

  // Helper function which reloads the current isolate using |script|.
  static Dart_Handle ReloadTestScript(const char* script);

  static void AddTestLib(const char* url, const char* source);
  static const char* GetTestLib(const char* url);

 private:
  static Dart_Isolate CreateIsolate(const uint8_t* buffer, const char* name);

  RunEntry* const run_;
};


class TestIsolateScope {
 public:
  TestIsolateScope() {
    isolate_ = reinterpret_cast<Isolate*>(TestCase::CreateTestIsolate());
    Dart_EnterScope();  // Create a Dart API scope for unit tests.
  }
  ~TestIsolateScope() {
    Dart_ExitScope();  // Exit the Dart API scope created for unit tests.
    ASSERT(isolate_ == Isolate::Current());
    Dart_ShutdownIsolate();
    isolate_ = NULL;
  }
  Isolate* isolate() const { return isolate_; }

 private:
  Isolate* isolate_;

  DISALLOW_COPY_AND_ASSIGN(TestIsolateScope);
};


template <typename T>
struct is_void {
  static const bool value = false;
};


template <>
struct is_void<void> {
  static const bool value = true;
};


template <typename T>
struct is_double {
  static const bool value = false;
};


template <>
struct is_double<double> {
  static const bool value = true;
};


class AssemblerTest {
 public:
  AssemblerTest(const char* name, Assembler* assembler)
      : name_(name), assembler_(assembler), code_(Code::ZoneHandle()) {
    ASSERT(name != NULL);
    ASSERT(assembler != NULL);
  }
  ~AssemblerTest() {}

  Assembler* assembler() const { return assembler_; }

  const Code& code() const { return code_; }

  uword payload_start() const { return code_.PayloadStart(); }
  uword entry() const { return code_.UncheckedEntryPoint(); }

// Invoke/InvokeWithCodeAndThread is used to call assembler test functions
// using the ABI calling convention.
// ResultType is the return type of the assembler test function.
// ArgNType is the type of the Nth argument.
#if defined(USING_SIMULATOR) && !defined(TARGET_ARCH_DBC)

#if defined(ARCH_IS_64_BIT)
  // TODO(fschneider): Make InvokeWithCodeAndThread<> more general and work on
  // 32-bit.
  // Since Simulator::Call always return a int64_t, bit_cast does not work
  // on 32-bit platforms when returning an int32_t. Since template functions
  // don't support partial specialization, we'd need to introduce a helper
  // class to support 32-bit return types.
  template <typename ResultType>
  ResultType InvokeWithCodeAndThread() {
    const bool fp_return = is_double<ResultType>::value;
    const bool fp_args = false;
    Thread* thread = Thread::Current();
    ASSERT(thread != NULL);
    return bit_cast<ResultType, int64_t>(Simulator::Current()->Call(
        bit_cast<intptr_t, uword>(entry()), reinterpret_cast<intptr_t>(&code_),
        reinterpret_cast<intptr_t>(thread), 0, 0, fp_return, fp_args));
  }
  template <typename ResultType, typename Arg1Type>
  ResultType InvokeWithCodeAndThread(Arg1Type arg1) {
    const bool fp_return = is_double<ResultType>::value;
    const bool fp_args = is_double<Arg1Type>::value;
    // TODO(fschneider): Support double arguments for simulator calls.
    COMPILE_ASSERT(!fp_args);
    Thread* thread = Thread::Current();
    ASSERT(thread != NULL);
    return bit_cast<ResultType, int64_t>(Simulator::Current()->Call(
        bit_cast<intptr_t, uword>(entry()), reinterpret_cast<intptr_t>(&code_),
        reinterpret_cast<intptr_t>(thread), reinterpret_cast<intptr_t>(arg1), 0,
        fp_return, fp_args));
  }
#endif  // ARCH_IS_64_BIT

  template <typename ResultType,
            typename Arg1Type,
            typename Arg2Type,
            typename Arg3Type>
  ResultType Invoke(Arg1Type arg1, Arg2Type arg2, Arg3Type arg3) {
    // TODO(fschneider): Support double arguments for simulator calls.
    COMPILE_ASSERT(is_void<ResultType>::value);
    COMPILE_ASSERT(!is_double<Arg1Type>::value);
    COMPILE_ASSERT(!is_double<Arg2Type>::value);
    COMPILE_ASSERT(!is_double<Arg3Type>::value);
    const bool fp_args = false;
    const bool fp_return = false;
    Simulator::Current()->Call(
        bit_cast<intptr_t, uword>(entry()), reinterpret_cast<intptr_t>(arg1),
        reinterpret_cast<intptr_t>(arg2), reinterpret_cast<intptr_t>(arg3), 0,
        fp_return, fp_args);
  }
#elif defined(USING_SIMULATOR) && defined(TARGET_ARCH_DBC)
  template <typename ResultType,
            typename Arg1Type,
            typename Arg2Type,
            typename Arg3Type>
  ResultType Invoke(Arg1Type arg1, Arg2Type arg2, Arg3Type arg3) {
    // TODO(fschneider): Support double arguments for simulator calls.
    COMPILE_ASSERT(is_void<ResultType>::value);
    COMPILE_ASSERT(!is_double<Arg1Type>::value);
    COMPILE_ASSERT(!is_double<Arg2Type>::value);
    COMPILE_ASSERT(!is_double<Arg3Type>::value);
    const Object& arg1obj = Object::Handle(reinterpret_cast<RawObject*>(arg1));
    const Object& arg2obj = Object::Handle(reinterpret_cast<RawObject*>(arg2));
    const Array& argdesc = Array::Handle(ArgumentsDescriptor::New(2));
    const Array& arguments = Array::Handle(Array::New(2));
    arguments.SetAt(0, arg1obj);
    arguments.SetAt(1, arg2obj);
    Simulator::Current()->Call(code(), argdesc, arguments,
                               reinterpret_cast<Thread*>(arg3));
  }
#else
  template <typename ResultType>
  ResultType InvokeWithCodeAndThread() {
    Thread* thread = Thread::Current();
    ASSERT(thread != NULL);
    typedef ResultType (*FunctionType)(const Code&, Thread*);
    return reinterpret_cast<FunctionType>(entry())(code_, thread);
  }

  template <typename ResultType, typename Arg1Type>
  ResultType InvokeWithCodeAndThread(Arg1Type arg1) {
    Thread* thread = Thread::Current();
    ASSERT(thread != NULL);
    typedef ResultType (*FunctionType)(const Code&, Thread*, Arg1Type);
    return reinterpret_cast<FunctionType>(entry())(code_, thread, arg1);
  }

  template <typename ResultType,
            typename Arg1Type,
            typename Arg2Type,
            typename Arg3Type>
  ResultType Invoke(Arg1Type arg1, Arg2Type arg2, Arg3Type arg3) {
    typedef ResultType (*FunctionType)(Arg1Type, Arg2Type, Arg3Type);
    return reinterpret_cast<FunctionType>(entry())(arg1, arg2, arg3);
  }
#endif  // defined(USING_SIMULATOR) && !defined(TARGET_ARCH_DBC)

  // Assemble test and set code_.
  void Assemble();

 private:
  const char* name_;
  Assembler* assembler_;
  Code& code_;

  DISALLOW_COPY_AND_ASSIGN(AssemblerTest);
};


class CodeGenTest {
 public:
  explicit CodeGenTest(const char* name);
  ~CodeGenTest() {}

  // Accessors.
  const Function& function() const { return function_; }

  SequenceNode* node_sequence() const { return node_sequence_; }

  void set_default_parameter_values(ZoneGrowableArray<const Instance*>* value) {
    default_parameter_values_ = value;
  }

  // Compile test and set code in function.
  void Compile();

 private:
  Function& function_;
  SequenceNode* node_sequence_;
  ZoneGrowableArray<const Instance*>* default_parameter_values_;

  DISALLOW_COPY_AND_ASSIGN(CodeGenTest);
};


class CompilerTest : public AllStatic {
 public:
  // Test the Compiler::CompileScript functionality by checking the return
  // value to see if no parse errors were reported.
  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 (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)

#define EXPECT_ERROR(handle, substring)                                        \
  do {                                                                         \
    Dart_Handle tmp_handle = (handle);                                         \
    if (Dart_IsError(tmp_handle)) {                                            \
      dart::Expect(__FILE__, __LINE__)                                         \
          .IsSubstring((substring), Dart_GetError(tmp_handle));                \
    } else {                                                                   \
      dart::Expect(__FILE__, __LINE__)                                         \
          .Fail(                                                               \
              "expected '%s' to be an error handle but found a valid "         \
              "handle.\n",                                                     \
              #handle);                                                        \
    }                                                                          \
  } while (0)

#define EXPECT_TRUE(handle)                                                    \
  do {                                                                         \
    Dart_Handle tmp_handle = (handle);                                         \
    if (Dart_IsBoolean(tmp_handle)) {                                          \
      bool value;                                                              \
      Dart_BooleanValue(tmp_handle, &value);                                   \
      if (!value) {                                                            \
        dart::Expect(__FILE__, __LINE__)                                       \
            .Fail("expected True, but was '%s'\n", #handle);                   \
      }                                                                        \
    } else {                                                                   \
      dart::Expect(__FILE__, __LINE__)                                         \
          .Fail("expected True, but was '%s'\n", #handle);                     \
    }                                                                          \
  } while (0)


// Elide a substring which starts with some prefix and ends with a ".
//
// This is used to remove non-deterministic or fragile substrings from
// JSON output.
//
// For example:
//
//    prefix = "classes"
//    in = "\"id\":\"classes/46\""
//
// Yields:
//
//    out = "\"id\":\"\""
//
void ElideJSONSubstring(const char* prefix, const char* in, char* out);


template <typename T>
class SetFlagScope : public ValueObject {
 public:
  SetFlagScope(T* flag, T value) : flag_(flag), original_value_(*flag) {
    *flag_ = value;
  }

  ~SetFlagScope() { *flag_ = original_value_; }

 private:
  T* flag_;
  T original_value_;
};

}  // namespace dart

#endif  // RUNTIME_VM_UNIT_TEST_H_