chromium/src/third_party/blink/renderer/bindings/core/v8/script_promise_tester.h

// Copyright 2019 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.

#ifndef THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_PROMISE_TESTER_H_
#define THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_PROMISE_TESTER_H_

#include "base/memory/weak_ptr.h"
#include "third_party/blink/renderer/bindings/core/v8/script_value.h"
#include "third_party/blink/renderer/platform/heap/visitor.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"

namespace blink {

class ScriptState;
class ScriptPromise;

// Utility for writing unit tests involving promises.
// Typical usage:
//   ScriptPromiseTester tester(script_state, script_promise);
//   tester.WaitUntilSettled();  // Runs a nested event loop.
//   EXPECT_TRUE(tester.IsFulfilled());
//   EXPECT_TRUE(tester.Value().IsUndefined());
class ScriptPromiseTester final {
  DISALLOW_NEW();

 public:
  ScriptPromiseTester(ScriptState*, ScriptPromise);

  // Run microtasks and tasks until the promise is either fulfilled or rejected.
  // If the promise never settles this will busy loop until the test times out.
  void WaitUntilSettled();

  // Did the promise fulfill?
  bool IsFulfilled() const { return state_ == State::kFulfilled; }

  // Did the promise reject?
  bool IsRejected() const { return state_ == State::kRejected; }

  // The value the promise fulfilled or rejected with.
  ScriptValue Value() const;

  void Trace(Visitor*) const;

 private:
  class ThenFunction;

  enum class State { kNotSettled, kFulfilled, kRejected };

  Member<ScriptState> script_state_;
  State state_ = State::kNotSettled;
  ScriptValue value_;

  base::WeakPtrFactory<ScriptPromiseTester> weak_factory_{this};

  DISALLOW_COPY_AND_ASSIGN(ScriptPromiseTester);
};

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_BINDINGS_CORE_V8_SCRIPT_PROMISE_TESTER_H_