root/gpu/command_buffer/client/cmd_buffer_helper_test.cc

DEFINITIONS

1. last_flush_
2. Flush
3. LockFlush
4. UnlockFlush
5. WaitForGetOffsetInRange
6. SetUp
7. TearDown
8. GetParser
9. ImmediateEntryCount
10. AddCommandWithExpect
11. AddUniqueCommandWithExpect
12. TestCommandWrappingFull
13. CheckFreeSpace
14. GetGetOffset
15. GetPutOffset
16. GetHelperGetOffset
17. GetHelperPutOffset
18. GetHelperFlushGeneration
19. GetError
20. get_helper_put
21. TEST_F
22. TEST_F
23. TEST_F
24. TEST_F
25. TEST_F
26. TEST_F
27. TEST_F
28. TEST_F
29. TEST_F
30. TEST_F
31. TEST_F
32. TEST_F
33. TEST_F
34. TEST_F
35. TEST_F
36. TEST_F
37. TEST_F
38. TEST_F
39. TEST_F

// Copyright (c) 2012 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.

// Tests for the Command Buffer Helper.

#include <list>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/memory/linked_ptr.h"
#include "base/message_loop/message_loop.h"
#include "gpu/command_buffer/client/cmd_buffer_helper.h"
#include "gpu/command_buffer/service/command_buffer_service.h"
#include "gpu/command_buffer/service/gpu_scheduler.h"
#include "gpu/command_buffer/service/mocks.h"
#include "gpu/command_buffer/service/transfer_buffer_manager.h"
#include "testing/gtest/include/gtest/gtest.h"

#if defined(OS_MACOSX)
#include "base/mac/scoped_nsautorelease_pool.h"
#endif

namespace gpu {

using testing::Return;
using testing::Mock;
using testing::Truly;
using testing::Sequence;
using testing::DoAll;
using testing::Invoke;
using testing::_;

const int32 kTotalNumCommandEntries = 32;
const int32 kCommandBufferSizeBytes =
    kTotalNumCommandEntries * sizeof(CommandBufferEntry);
const int32 kUnusedCommandId = 5;  // we use 0 and 2 currently.

// Override CommandBufferService::Flush() to lock flushing and simulate
// the buffer becoming full in asynchronous mode.
class CommandBufferServiceLocked : public CommandBufferService {
 public:
  explicit CommandBufferServiceLocked(
      TransferBufferManagerInterface* transfer_buffer_manager)
      : CommandBufferService(transfer_buffer_manager),
        flush_locked_(false),
        last_flush_(-1) {}
  virtual ~CommandBufferServiceLocked() {}

  virtual void Flush(int32 put_offset) OVERRIDE {
    if (!flush_locked_) {
      last_flush_ = -1;
      CommandBufferService::Flush(put_offset);
    } else {
      last_flush_ = put_offset;
    }
  }

  void LockFlush() { flush_locked_ = true; }

  void UnlockFlush() { flush_locked_ = false; }

  virtual void WaitForGetOffsetInRange(int32 start, int32 end) OVERRIDE {
    if (last_flush_ != -1) {
      CommandBufferService::Flush(last_flush_);
      last_flush_ = -1;
    }
    CommandBufferService::WaitForGetOffsetInRange(start, end);
  }

 private:
  bool flush_locked_;
  int last_flush_;
  DISALLOW_COPY_AND_ASSIGN(CommandBufferServiceLocked);
};

// Test fixture for CommandBufferHelper test - Creates a CommandBufferHelper,
// using a CommandBufferEngine with a mock AsyncAPIInterface for its interface
// (calling it directly, not through the RPC mechanism).
class CommandBufferHelperTest : public testing::Test {
 protected:
  virtual void SetUp() {
    api_mock_.reset(new AsyncAPIMock);
    // ignore noops in the mock - we don't want to inspect the internals of the
    // helper.
    EXPECT_CALL(*api_mock_, DoCommand(cmd::kNoop, _, _))
        .WillRepeatedly(Return(error::kNoError));

    {
      TransferBufferManager* manager = new TransferBufferManager();
      transfer_buffer_manager_.reset(manager);
      EXPECT_TRUE(manager->Initialize());
    }
    command_buffer_.reset(
        new CommandBufferServiceLocked(transfer_buffer_manager_.get()));
    EXPECT_TRUE(command_buffer_->Initialize());

    gpu_scheduler_.reset(new GpuScheduler(
        command_buffer_.get(), api_mock_.get(), NULL));
    command_buffer_->SetPutOffsetChangeCallback(base::Bind(
        &GpuScheduler::PutChanged, base::Unretained(gpu_scheduler_.get())));
    command_buffer_->SetGetBufferChangeCallback(base::Bind(
        &GpuScheduler::SetGetBuffer, base::Unretained(gpu_scheduler_.get())));

    api_mock_->set_engine(gpu_scheduler_.get());

    helper_.reset(new CommandBufferHelper(command_buffer_.get()));
    helper_->Initialize(kCommandBufferSizeBytes);

    test_command_next_id_ = kUnusedCommandId;
  }

  virtual void TearDown() {
    // If the GpuScheduler posts any tasks, this forces them to run.
    base::MessageLoop::current()->RunUntilIdle();
    test_command_args_.clear();
  }

  const CommandParser* GetParser() const {
    return gpu_scheduler_->parser();
  }

  int32 ImmediateEntryCount() const { return helper_->immediate_entry_count_; }

  // Adds a command to the buffer through the helper, while adding it as an
  // expected call on the API mock.
  void AddCommandWithExpect(error::Error _return,
                            unsigned int command,
                            int arg_count,
                            CommandBufferEntry *args) {
    CommandHeader header;
    header.size = arg_count + 1;
    header.command = command;
    CommandBufferEntry* cmds = helper_->GetSpace(arg_count + 1);
    CommandBufferOffset put = 0;
    cmds[put++].value_header = header;
    for (int ii = 0; ii < arg_count; ++ii) {
      cmds[put++] = args[ii];
    }

    EXPECT_CALL(*api_mock_, DoCommand(command, arg_count,
        Truly(AsyncAPIMock::IsArgs(arg_count, args))))
        .InSequence(sequence_)
        .WillOnce(Return(_return));
  }

  void AddUniqueCommandWithExpect(error::Error _return, int cmd_size) {
    EXPECT_GE(cmd_size, 1);
    EXPECT_LT(cmd_size, kTotalNumCommandEntries);
    int arg_count = cmd_size - 1;

    // Allocate array for args.
    linked_ptr<std::vector<CommandBufferEntry> > args_ptr(
        new std::vector<CommandBufferEntry>(arg_count ? arg_count : 1));

    for (int32 ii = 0; ii < arg_count; ++ii) {
      (*args_ptr)[ii].value_uint32 = 0xF00DF00D + ii;
    }

    // Add command and save args in test_command_args_ until the test completes.
    AddCommandWithExpect(
        _return, test_command_next_id_++, arg_count, &(*args_ptr)[0]);
    test_command_args_.insert(test_command_args_.end(), args_ptr);
  }

  void TestCommandWrappingFull(int32 cmd_size, int32 start_commands) {
    const int32 num_args = cmd_size - 1;
    EXPECT_EQ(kTotalNumCommandEntries % cmd_size, 0);

    std::vector<CommandBufferEntry> args(num_args);
    for (int32 ii = 0; ii < num_args; ++ii) {
      args[ii].value_uint32 = ii + 1;
    }

    // Initially insert commands up to start_commands and Finish().
    for (int32 ii = 0; ii < start_commands; ++ii) {
      AddCommandWithExpect(
          error::kNoError, ii + kUnusedCommandId, num_args, &args[0]);
    }
    helper_->Finish();

    EXPECT_EQ(GetParser()->put(),
              (start_commands * cmd_size) % kTotalNumCommandEntries);
    EXPECT_EQ(GetParser()->get(),
              (start_commands * cmd_size) % kTotalNumCommandEntries);

    // Lock flushing to force the buffer to get full.
    command_buffer_->LockFlush();

    // Add enough commands to over fill the buffer.
    for (int32 ii = 0; ii < kTotalNumCommandEntries / cmd_size + 2; ++ii) {
      AddCommandWithExpect(error::kNoError,
                           start_commands + ii + kUnusedCommandId,
                           num_args,
                           &args[0]);
    }

    // Flush all commands.
    command_buffer_->UnlockFlush();
    helper_->Finish();

    // Check that the commands did happen.
    Mock::VerifyAndClearExpectations(api_mock_.get());

    // Check the error status.
    EXPECT_EQ(error::kNoError, GetError());
  }

  // Checks that the buffer from put to put+size is free in the parser.
  void CheckFreeSpace(CommandBufferOffset put, unsigned int size) {
    CommandBufferOffset parser_put = GetParser()->put();
    CommandBufferOffset parser_get = GetParser()->get();
    CommandBufferOffset limit = put + size;
    if (parser_get > parser_put) {
      // "busy" buffer wraps, so "free" buffer is between put (inclusive) and
      // get (exclusive).
      EXPECT_LE(parser_put, put);
      EXPECT_GT(parser_get, limit);
    } else {
      // "busy" buffer does not wrap, so the "free" buffer is the top side (from
      // put to the limit) and the bottom side (from 0 to get).
      if (put >= parser_put) {
        // we're on the top side, check we are below the limit.
        EXPECT_GE(kTotalNumCommandEntries, limit);
      } else {
        // we're on the bottom side, check we are below get.
        EXPECT_GT(parser_get, limit);
      }
    }
  }

  int32 GetGetOffset() {
    return command_buffer_->GetState().get_offset;
  }

  int32 GetPutOffset() {
    return command_buffer_->GetState().put_offset;
  }

  int32 GetHelperGetOffset() { return helper_->get_offset(); }

  int32 GetHelperPutOffset() { return helper_->put_; }

  uint32 GetHelperFlushGeneration() { return helper_->flush_generation(); }

  error::Error GetError() {
    return command_buffer_->GetState().error;
  }

  CommandBufferOffset get_helper_put() { return helper_->put_; }

#if defined(OS_MACOSX)
  base::mac::ScopedNSAutoreleasePool autorelease_pool_;
#endif
  base::MessageLoop message_loop_;
  scoped_ptr<AsyncAPIMock> api_mock_;
  scoped_ptr<TransferBufferManagerInterface> transfer_buffer_manager_;
  scoped_ptr<CommandBufferServiceLocked> command_buffer_;
  scoped_ptr<GpuScheduler> gpu_scheduler_;
  scoped_ptr<CommandBufferHelper> helper_;
  std::list<linked_ptr<std::vector<CommandBufferEntry> > > test_command_args_;
  unsigned int test_command_next_id_;
  Sequence sequence_;
};

// Checks immediate_entry_count_ changes based on 'usable' state.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesNotUsable) {
  // Auto flushing mode is tested separately.
  helper_->SetAutomaticFlushes(false);
  EXPECT_EQ(helper_->usable(), true);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 1);
  helper_->ClearUsable();
  EXPECT_EQ(ImmediateEntryCount(), 0);
}

// Checks immediate_entry_count_ changes based on RingBuffer state.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesNoRingBuffer) {
  helper_->SetAutomaticFlushes(false);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 1);
  helper_->FreeRingBuffer();
  EXPECT_EQ(ImmediateEntryCount(), 0);
}

// Checks immediate_entry_count_ calc when Put >= Get and Get == 0.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesGetAtZero) {
  // No internal auto flushing.
  helper_->SetAutomaticFlushes(false);
  command_buffer_->LockFlush();

  // Start at Get = Put = 0.
  EXPECT_EQ(GetHelperPutOffset(), 0);
  EXPECT_EQ(GetHelperGetOffset(), 0);

  // Immediate count should be 1 less than the end of the buffer.
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 1);
  AddUniqueCommandWithExpect(error::kNoError, 2);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 3);

  helper_->Finish();

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks immediate_entry_count_ calc when Put >= Get and Get > 0.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesGetInMiddle) {
  // No internal auto flushing.
  helper_->SetAutomaticFlushes(false);
  command_buffer_->LockFlush();

  // Move to Get = Put = 2.
  AddUniqueCommandWithExpect(error::kNoError, 2);
  helper_->Finish();
  EXPECT_EQ(GetHelperPutOffset(), 2);
  EXPECT_EQ(GetHelperGetOffset(), 2);

  // Immediate count should be up to the end of the buffer.
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 2);
  AddUniqueCommandWithExpect(error::kNoError, 2);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 4);

  helper_->Finish();

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks immediate_entry_count_ calc when Put < Get.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesGetBeforePut) {
  // Move to Get = kTotalNumCommandEntries / 4, Put = 0.
  const int kInitGetOffset = kTotalNumCommandEntries / 4;
  helper_->SetAutomaticFlushes(false);
  command_buffer_->LockFlush();
  AddUniqueCommandWithExpect(error::kNoError, kInitGetOffset);
  helper_->Finish();
  AddUniqueCommandWithExpect(error::kNoError,
                             kTotalNumCommandEntries - kInitGetOffset);

  // Flush instead of Finish will let Put wrap without the command buffer
  // immediately processing the data between Get and Put.
  helper_->Flush();

  EXPECT_EQ(GetHelperGetOffset(), kInitGetOffset);
  EXPECT_EQ(GetHelperPutOffset(), 0);

  // Immediate count should be up to Get - 1.
  EXPECT_EQ(ImmediateEntryCount(), kInitGetOffset - 1);
  AddUniqueCommandWithExpect(error::kNoError, 2);
  EXPECT_EQ(ImmediateEntryCount(), kInitGetOffset - 3);

  helper_->Finish();
  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks immediate_entry_count_ calc when automatic flushing is enabled.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesAutoFlushing) {
  command_buffer_->LockFlush();

  // Start at Get = Put = 0.
  EXPECT_EQ(GetHelperPutOffset(), 0);
  EXPECT_EQ(GetHelperGetOffset(), 0);

  // Without auto flushes, up to kTotalNumCommandEntries - 1 is available.
  helper_->SetAutomaticFlushes(false);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries - 1);

  // With auto flushes, and Get == Last Put,
  // up to kTotalNumCommandEntries / kAutoFlushSmall is available.
  helper_->SetAutomaticFlushes(true);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries / kAutoFlushSmall);

  // With auto flushes, and Get != Last Put,
  // up to kTotalNumCommandEntries / kAutoFlushBig is available.
  AddUniqueCommandWithExpect(error::kNoError, 2);
  helper_->Flush();
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries / kAutoFlushBig);

  helper_->Finish();
  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks immediate_entry_count_ calc when automatic flushing is enabled, and
// we allocate commands over the immediate_entry_count_ size.
TEST_F(CommandBufferHelperTest, TestCalcImmediateEntriesOverFlushLimit) {
  // Lock internal flushing.
  command_buffer_->LockFlush();

  // Start at Get = Put = 0.
  EXPECT_EQ(GetHelperPutOffset(), 0);
  EXPECT_EQ(GetHelperGetOffset(), 0);

  // Pre-check ImmediateEntryCount is limited with automatic flushing enabled.
  helper_->SetAutomaticFlushes(true);
  EXPECT_EQ(ImmediateEntryCount(), kTotalNumCommandEntries / kAutoFlushSmall);

  // Add a command larger than ImmediateEntryCount().
  AddUniqueCommandWithExpect(error::kNoError, ImmediateEntryCount() + 1);

  // ImmediateEntryCount() should now be 0, to force a flush check on the next
  // command.
  EXPECT_EQ(ImmediateEntryCount(), 0);

  // Add a command when ImmediateEntryCount() == 0.
  AddUniqueCommandWithExpect(error::kNoError, ImmediateEntryCount() + 1);

  helper_->Finish();
  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks that commands in the buffer are properly executed, and that the
// status/error stay valid.
TEST_F(CommandBufferHelperTest, TestCommandProcessing) {
  // Check initial state of the engine - it should have been configured by the
  // helper.
  EXPECT_TRUE(GetParser() != NULL);
  EXPECT_EQ(error::kNoError, GetError());
  EXPECT_EQ(0, GetGetOffset());

  // Add 3 commands through the helper
  AddCommandWithExpect(error::kNoError, kUnusedCommandId, 0, NULL);

  CommandBufferEntry args1[2];
  args1[0].value_uint32 = 3;
  args1[1].value_float = 4.f;
  AddCommandWithExpect(error::kNoError, kUnusedCommandId, 2, args1);

  CommandBufferEntry args2[2];
  args2[0].value_uint32 = 5;
  args2[1].value_float = 6.f;
  AddCommandWithExpect(error::kNoError, kUnusedCommandId, 2, args2);

  // Wait until it's done.
  helper_->Finish();
  // Check that the engine has no more work to do.
  EXPECT_TRUE(GetParser()->IsEmpty());

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks that commands in the buffer are properly executed when wrapping the
// buffer, and that the status/error stay valid.
TEST_F(CommandBufferHelperTest, TestCommandWrapping) {
  // Add num_commands * commands of size 3 through the helper to make sure we
  // do wrap.  kTotalNumCommandEntries must not be a multiple of 3.
  COMPILE_ASSERT(kTotalNumCommandEntries % 3 != 0,
                 Is_multiple_of_num_command_entries);
  const int kNumCommands = (kTotalNumCommandEntries / 3) * 2;
  CommandBufferEntry args1[2];
  args1[0].value_uint32 = 5;
  args1[1].value_float = 4.f;

  for (int i = 0; i < kNumCommands; ++i) {
    AddCommandWithExpect(error::kNoError, kUnusedCommandId + i, 2, args1);
  }

  helper_->Finish();
  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks the case where the command inserted exactly matches the space left in
// the command buffer.
TEST_F(CommandBufferHelperTest, TestCommandWrappingExactMultiple) {
  const int32 kCommandSize = kTotalNumCommandEntries / 2;
  const size_t kNumArgs = kCommandSize - 1;
  COMPILE_ASSERT(kTotalNumCommandEntries % kCommandSize == 0,
                 Not_multiple_of_num_command_entries);
  CommandBufferEntry args1[kNumArgs];
  for (size_t ii = 0; ii < kNumArgs; ++ii) {
    args1[ii].value_uint32 = ii + 1;
  }

  for (unsigned int i = 0; i < 5; ++i) {
    AddCommandWithExpect(
        error::kNoError, i + kUnusedCommandId, kNumArgs, args1);
  }

  helper_->Finish();
  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks exact wrapping condition with Get = 0.
TEST_F(CommandBufferHelperTest, TestCommandWrappingFullAtStart) {
  TestCommandWrappingFull(2, 0);
}

// Checks exact wrapping condition with 0 < Get < kTotalNumCommandEntries.
TEST_F(CommandBufferHelperTest, TestCommandWrappingFullInMiddle) {
  TestCommandWrappingFull(2, 1);
}

// Checks exact wrapping condition with Get = kTotalNumCommandEntries.
// Get should wrap back to 0, but making sure.
TEST_F(CommandBufferHelperTest, TestCommandWrappingFullAtEnd) {
  TestCommandWrappingFull(2, kTotalNumCommandEntries / 2);
}

// Checks that asking for available entries work, and that the parser
// effectively won't use that space.
TEST_F(CommandBufferHelperTest, TestAvailableEntries) {
  CommandBufferEntry args[2];
  args[0].value_uint32 = 3;
  args[1].value_float = 4.f;

  // Add 2 commands through the helper - 8 entries
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 1, 0, NULL);
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 2, 0, NULL);
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 3, 2, args);
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 4, 2, args);

  // Ask for 5 entries.
  helper_->WaitForAvailableEntries(5);

  CommandBufferOffset put = get_helper_put();
  CheckFreeSpace(put, 5);

  // Add more commands.
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 5, 2, args);

  // Wait until everything is done done.
  helper_->Finish();

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

// Checks that the InsertToken/WaitForToken work.
TEST_F(CommandBufferHelperTest, TestToken) {
  CommandBufferEntry args[2];
  args[0].value_uint32 = 3;
  args[1].value_float = 4.f;

  // Add a first command.
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 3, 2, args);
  // keep track of the buffer position.
  CommandBufferOffset command1_put = get_helper_put();
  int32 token = helper_->InsertToken();

  EXPECT_CALL(*api_mock_.get(), DoCommand(cmd::kSetToken, 1, _))
      .WillOnce(DoAll(Invoke(api_mock_.get(), &AsyncAPIMock::SetToken),
                      Return(error::kNoError)));
  // Add another command.
  AddCommandWithExpect(error::kNoError, kUnusedCommandId + 4, 2, args);
  helper_->WaitForToken(token);
  // check that the get pointer is beyond the first command.
  EXPECT_LE(command1_put, GetGetOffset());
  helper_->Finish();

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

TEST_F(CommandBufferHelperTest, FreeRingBuffer) {
  EXPECT_TRUE(helper_->HaveRingBuffer());

  // Test freeing ring buffer.
  helper_->FreeRingBuffer();
  EXPECT_FALSE(helper_->HaveRingBuffer());

  // Test that InsertToken allocates a new one
  int32 token = helper_->InsertToken();
  EXPECT_TRUE(helper_->HaveRingBuffer());
  EXPECT_CALL(*api_mock_.get(), DoCommand(cmd::kSetToken, 1, _))
      .WillOnce(DoAll(Invoke(api_mock_.get(), &AsyncAPIMock::SetToken),
                      Return(error::kNoError)));
  helper_->WaitForToken(token);
  helper_->FreeRingBuffer();
  EXPECT_FALSE(helper_->HaveRingBuffer());

  // Test that WaitForAvailableEntries allocates a new one
  AddCommandWithExpect(error::kNoError, kUnusedCommandId, 0, NULL);
  EXPECT_TRUE(helper_->HaveRingBuffer());
  helper_->Finish();
  helper_->FreeRingBuffer();
  EXPECT_FALSE(helper_->HaveRingBuffer());

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());
}

TEST_F(CommandBufferHelperTest, Noop) {
  for (int ii = 1; ii < 4; ++ii) {
    CommandBufferOffset put_before = get_helper_put();
    helper_->Noop(ii);
    CommandBufferOffset put_after = get_helper_put();
    EXPECT_EQ(ii, put_after - put_before);
  }
}

TEST_F(CommandBufferHelperTest, IsContextLost) {
  EXPECT_FALSE(helper_->IsContextLost());
  command_buffer_->SetParseError(error::kGenericError);
  EXPECT_TRUE(helper_->IsContextLost());
}

// Checks helper's 'flush generation' updates.
TEST_F(CommandBufferHelperTest, TestFlushGeneration) {
  // Explicit flushing only.
  helper_->SetAutomaticFlushes(false);

  // Generation should change after Flush() but not before.
  uint32 gen1, gen2, gen3;

  gen1 = GetHelperFlushGeneration();
  AddUniqueCommandWithExpect(error::kNoError, 2);
  gen2 = GetHelperFlushGeneration();
  helper_->Flush();
  gen3 = GetHelperFlushGeneration();
  EXPECT_EQ(gen2, gen1);
  EXPECT_NE(gen3, gen2);

  // Generation should change after Finish() but not before.
  gen1 = GetHelperFlushGeneration();
  AddUniqueCommandWithExpect(error::kNoError, 2);
  gen2 = GetHelperFlushGeneration();
  helper_->Finish();
  gen3 = GetHelperFlushGeneration();
  EXPECT_EQ(gen2, gen1);
  EXPECT_NE(gen3, gen2);

  helper_->Finish();

  // Check that the commands did happen.
  Mock::VerifyAndClearExpectations(api_mock_.get());

  // Check the error status.
  EXPECT_EQ(error::kNoError, GetError());
}

}  // namespace gpu