[Impeller] Add MockFence to mock_vulkan.

impeller/renderer/backend/vulkan/test/mock_vulkan.cc

@@ -4,10 +4,13 @@
 
 #include "impeller/renderer/backend/vulkan/test/mock_vulkan.h"
 #include <cstring>
+#include <utility>
 #include <vector>
 #include "fml/macros.h"
 #include "fml/thread_local.h"
 #include "impeller/base/thread_safety.h"
+#include "vulkan/vulkan_core.h"
+#include "vulkan/vulkan_enums.hpp"
 
 namespace impeller {
 namespace testing {
@@ -410,7 +413,8 @@ VkResult vkCreateFence(VkDevice device,
                        const VkFenceCreateInfo* pCreateInfo,
                        const VkAllocationCallbacks* pAllocator,
                        VkFence* pFence) {
-  *pFence = reinterpret_cast<VkFence>(0xfe0ce);
+  MockDevice* mock_device = reinterpret_cast<MockDevice*>(device);
+  *pFence = reinterpret_cast<VkFence>(new MockFence());
   return VK_SUCCESS;
 }
 
@@ -430,7 +434,9 @@ VkResult vkWaitForFences(VkDevice device,
 }
 
 VkResult vkGetFenceStatus(VkDevice device, VkFence fence) {
-  return VK_SUCCESS;
+  MockDevice* mock_device = reinterpret_cast<MockDevice*>(device);
+  MockFence* mock_fence = reinterpret_cast<MockFence*>(fence);
+  return mock_fence->GetStatus();
 }
 
 VkResult vkCreateDebugUtilsMessengerEXT(

impeller/renderer/backend/vulkan/test/mock_vulkan.h

@@ -5,17 +5,41 @@
 #pragma once
 
 #include <functional>
+#include <memory>
 #include <string>
 #include <vector>
 
 #include "impeller/renderer/backend/vulkan/context_vk.h"
+#include "vulkan/vulkan_enums.hpp"
 
 namespace impeller {
 namespace testing {
 
 std::shared_ptr<std::vector<std::string>> GetMockVulkanFunctions(
     VkDevice device);
 
+// A test-controlled version of |vk::Fence|.
+class MockFence final {
+ public:
+  MockFence() = default;
+
+  // Returns the result that was set in the constructor or |SetStatus|.
+  VkResult GetStatus() { return static_cast<VkResult>(result_); }
+
+  // Sets the result that will be returned by `GetFenceStatus`.
+  static void SetStatus(vk::UniqueFence& fence, vk::Result result) {
+    // Cast the fence to a MockFence and set the result.
+    VkFence raw_fence = fence.get();
+    MockFence* mock_fence = reinterpret_cast<MockFence*>(raw_fence);
+    mock_fence->result_ = result;
+  }
+
+ private:
+  vk::Result result_ = vk::Result::eSuccess;
+
+  FML_DISALLOW_COPY_AND_ASSIGN(MockFence);
+};
+
 class MockVulkanContextBuilder {
  public:
   MockVulkanContextBuilder();

impeller/renderer/backend/vulkan/test/mock_vulkan_unittests.cc

@@ -6,6 +6,7 @@
 #include "gtest/gtest.h"
 #include "impeller/renderer/backend/vulkan/command_pool_vk.h"
 #include "impeller/renderer/backend/vulkan/test/mock_vulkan.h"
+#include "vulkan/vulkan_enums.hpp"
 
 namespace impeller {
 namespace testing {
@@ -33,5 +34,26 @@ TEST(MockVulkanContextTest, IsThreadSafe) {
   context->Shutdown();
 }
 
+TEST(MockVulkanContextTest, DefaultFenceAlwaysReportsSuccess) {
+  auto const context = MockVulkanContextBuilder().Build();
+  auto const device = context->GetDevice();
+
+  auto fence = device.createFenceUnique({}).value;
+  EXPECT_EQ(vk::Result::eSuccess, device.getFenceStatus(*fence));
+}
+
+TEST(MockVulkanContextTest, MockedFenceReportsStatus) {
+  auto const context = MockVulkanContextBuilder().Build();
+
+  auto const device = context->GetDevice();
+  auto fence = device.createFenceUnique({}).value;
+  MockFence::SetStatus(fence, vk::Result::eNotReady);
+
+  EXPECT_EQ(vk::Result::eNotReady, device.getFenceStatus(fence.get()));
+
+  MockFence::SetStatus(fence, vk::Result::eSuccess);
+  EXPECT_EQ(vk::Result::eSuccess, device.getFenceStatus(*fence));
+}
+
 }  // namespace testing
 }  // namespace impeller