o3de/Code/Framework/AzFramework/Tests/FrameworkApplicationFixture.h

/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */
#pragma once

#include <AzCore/std/typetraits/alignment_of.h>
#include <AzCore/std/typetraits/aligned_storage.h>
#include <AzFramework/Application/Application.h>
#include <AzCore/UserSettings/UserSettingsComponent.h>
#include <AzCore/IO/SystemFile.h>
#include <AzCore/UnitTest/TestTypes.h>

namespace AZ
{
    class Entity;
}

namespace UnitTest
{
    /**
     * Test fixture that starts up an AzFramework::Application.
     */
    class FrameworkApplicationFixture
        : public UnitTest::LeakDetectionFixture
    {
    protected:

        // HACK: Special Application that excludes UserSettingsComponent.
        // For some reason unit tests for different branches will read/write the same UserSettings.xml file,
        // but those tests may have different versions of serialization code for writing UserSettings.xml, thus 
        // causing version conflicts. Ideally unit tests should not interact with physical files on disk, after 
        // we fix this problem NoUserSettingsApplication should be removed, and we can use AzFramework::Application directly.
        class NoUserSettingsApplication
            : public AzFramework::Application
        {
            AZ::ComponentTypeList GetRequiredSystemComponents() const override
            {
                AZ::ComponentTypeList components = AzFramework::Application::GetRequiredSystemComponents();
                AZ::ComponentTypeList::iterator componentItr = AZStd::find(components.begin(), components.end(), azrtti_typeid<AZ::UserSettingsComponent>());
                if (componentItr != components.end())
                {
                    components.erase(componentItr);
                }
                return components;
            }
        };

        void SetUp() override
        {            
            m_appDescriptor.m_allocationRecordsSaveNames = true;
            m_appDescriptor.m_recordingMode = AZ::Debug::AllocationRecords::Mode::RECORD_FULL;
            m_application = new (AZStd::addressof(m_applicationBuffer)) NoUserSettingsApplication();
            AZ::ComponentApplication::StartupParameters startupParameters;
            m_appStartupParams.m_loadSettingsRegistry = false;
            m_application->Start(m_appDescriptor, m_appStartupParams);
        }

        void TearDown() override
        {
            m_application->~Application();
            m_application = nullptr;

            // Reset so next test can assume blank slate.
            m_appStartupParams = AzFramework::Application::StartupParameters();
            m_appDescriptor = AzFramework::Application::Descriptor();
        }

        // Customize the descriptor before SetUp() to affect the application's startup.
        AzFramework::Application::Descriptor m_appDescriptor;

        // Customize the startup params before SetUp() to affect the application's startup.
        AzFramework::Application::StartupParameters m_appStartupParams;

        // Can't store on the stack because the object must be properly destroyed on shutdown.
        // Can't use unique_ptr yet because the allocators aren't up yet.
        AZStd::aligned_storage<sizeof(NoUserSettingsApplication), AZStd::alignment_of<NoUserSettingsApplication>::value>::type m_applicationBuffer;
        AzFramework::Application* m_application;
    };
}