pagespeed/kernel/base/circular_buffer_test.cc

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */


#include <cstdlib>
#include "pagespeed/kernel/base/circular_buffer.h"
#include "pagespeed/kernel/base/mock_message_handler.h"
#include "pagespeed/kernel/base/null_mutex.h"
#include "pagespeed/kernel/base/gtest.h"

namespace net_instaweb {

class CircularBufferTest : public testing::Test {
 protected:
  CircularBufferTest() : handler_(new NullMutex) {}
  MockMessageHandler handler_;
};

// Instantiate CircularBuffer with malloc.
TEST_F(CircularBufferTest, InstantiateWithMalloc) {
  CircularBuffer* cb = CircularBuffer::Create(10);
  cb->Write("012345");
  EXPECT_EQ("012345", cb->ToString(&handler_));
  free(cb);
}

// Instantiate CircularBuffer with pre-allocated block of right size.
TEST_F(CircularBufferTest, InstantiateWithPreAllocatedBlock) {
  const int capacity = 10;
  const int segment_size = CircularBuffer::Sizeof(capacity);
  void* segment = static_cast<void*>(malloc(segment_size));
  CircularBuffer* cb = CircularBuffer::Init(true, segment,
                                            segment_size, capacity);
  if (cb != NULL) {
    cb->Write("0123456789");
  }
  EXPECT_EQ("0123456789", cb->ToString(&handler_));
  free(segment);
}

// Test circular buffer overwritten result.
TEST_F(CircularBufferTest, CircularWritten) {
  const int capacity = 10;
  CircularBuffer* cb = CircularBuffer::Create(capacity);
  cb->Write("012345");
  EXPECT_EQ("012345", cb->ToString(&handler_));
  cb->Write("67");
  EXPECT_EQ("01234567", cb->ToString(&handler_));
  // Buffer size is 10, it should be filled exactly so far.
  cb->Write("89");
  EXPECT_EQ("0123456789", cb->ToString(&handler_));
  // Lose the first char.
  cb->Write("a");
  EXPECT_EQ("123456789a", cb->ToString(&handler_));
  // Message size is larger than buffer size.
  cb->Write("bcdefghijkl");
  EXPECT_EQ("cdefghijkl", cb->ToString(&handler_));
  free(cb);
}

// Test the content after clear().
TEST_F(CircularBufferTest, OverWrittenAfterClear) {
  const int capacity = 10;
  CircularBuffer* cb = CircularBuffer::Create(capacity);
  cb->Write("0123456789");
  EXPECT_EQ("0123456789", cb->ToString(&handler_));
  cb->Clear();
  cb->Write("abc");
  EXPECT_EQ("abc", cb->ToString(&handler_));
  free(cb);
}

// Test corner case where buffer size is 1.
TEST_F(CircularBufferTest, SmallSize) {
  // CircularBuffer instantiated with malloc.
  const int capacity = 1;
  CircularBuffer* cb = CircularBuffer::Create(capacity);
  cb->Write("0");
  EXPECT_EQ("0", cb->ToString(&handler_));
  cb->Write("1");
  EXPECT_EQ("1", cb->ToString(&handler_));
  cb->Write("234");
  EXPECT_EQ("4", cb->ToString(&handler_));
  free(cb);
  // CircularBuffer instantiated with pre-allocated buffer.
  int segment_size = CircularBuffer::Sizeof(capacity);
  void* segment = static_cast<void*>(malloc(segment_size));
  CircularBuffer* temp = CircularBuffer::Init(true, segment,
                                              segment_size, capacity);
  temp->Write("0");
  EXPECT_EQ("0", temp->ToString(&handler_));
  temp->Write("1");
  EXPECT_EQ("1", temp->ToString(&handler_));
  temp->Write("234");
  EXPECT_EQ("4", temp->ToString(&handler_));
  free(temp);
}

}  // namespace net_instaweb