tracing v2: minor refactoring to TraceRingBuffer test helpers

components/tracing/core/scattered_stream_writer_unittest.cc

 // Copyright 2016 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.
 
 #include "components/tracing/core/scattered_stream_writer.h"
 
 #include <string.h>
 
 #include <memory>
 
@@ skipping 50 matching lines @@
   memcpy(reserved_range_1.begin, kFourByteBuf, sizeof(kFourByteBuf));
   memcpy(reserved_range_2.begin, kFourByteBuf, sizeof(kFourByteBuf));
   EXPECT_EQ(6u, delegate.chunks().size());
   EXPECT_EQ(7u, ssw.bytes_available());
 
   // Check that reserving more bytes than what left creates a brand new chunk
   // even if the previous one is not exhausted
   for (uint8_t i = 0; i < 5; ++i)
     ssw.WriteByte(0xFF);
   memcpy(ssw.ReserveBytes(4).begin, kFourByteBuf, sizeof(kFourByteBuf));
-  EXPECT_EQ(7u, delegate.chunks().size());
-  EXPECT_EQ(4u, ssw.bytes_available());
+  memcpy(ssw.ReserveBytesUnsafe(3), kThreeByteBuf, sizeof(kThreeByteBuf));
+  memcpy(ssw.ReserveBytes(3).begin, kThreeByteBuf, sizeof(kThreeByteBuf));
+  memcpy(ssw.ReserveBytesUnsafe(1), kOneByteBuf, sizeof(kOneByteBuf));
+  memcpy(ssw.ReserveBytes(1).begin, kOneByteBuf, sizeof(kOneByteBuf));
+
+  EXPECT_EQ(8u, delegate.chunks().size());
+  EXPECT_EQ(3u, ssw.bytes_available());
 
   EXPECT_EQ("0001020304050607", delegate.GetChunkAsString(0));
   EXPECT_EQ("4060616263FF5051", delegate.GetChunkAsString(1));
   EXPECT_EQ("5260616263A0A1A2", delegate.GetChunkAsString(2));
   EXPECT_EQ("A3A4A5A6A7A8A9AA", delegate.GetChunkAsString(3));
   EXPECT_EQ("ABACADAEAFB0B1B2", delegate.GetChunkAsString(4));
   EXPECT_EQ("B3FFFFFFFFFF0000", delegate.GetChunkAsString(5));
-  EXPECT_EQ("6061626300000000", delegate.GetChunkAsString(6));
+  EXPECT_EQ("6061626350515200", delegate.GetChunkAsString(6));
+  EXPECT_EQ("5051524040000000", delegate.GetChunkAsString(7));
 
   // Finally reset the writer to a new buffer.
   uint8_t other_buffer[8] = {0};
   ssw.Reset({other_buffer, other_buffer + sizeof(other_buffer)});
   EXPECT_EQ(other_buffer, ssw.write_ptr());
   ssw.WriteByte(1);
   ssw.WriteBytes(kThreeByteBuf, sizeof(kThreeByteBuf));
   EXPECT_EQ(1u, other_buffer[0]);
   EXPECT_EQ(0x52u, other_buffer[3]);
 }
 
 }  // namespace
 }  // namespace v2
 }  // namespace tracing