AU: Extent Mapper class

src/platform/update_engine/extent_mapper_unittest.cc

+// Copyright (c) 2010 The Chromium OS 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 <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <set>
+#include <string>
+#include <vector>
+#include <gtest/gtest.h>
+#include "base/basictypes.h"
+#include "update_engine/extent_mapper.h"
+#include "update_engine/utils.h"
+
+using std::set;
+using std::string;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+class ExtentMapperTest : public ::testing::Test {};
+
+TEST(ExtentMapperTest, RunAsRootSimpleTest) {
+  // It's hard to have a concrete test for extent mapping without including
+  // a specific filesystem image.
+  // In lieu of this, we do a weak test: make sure the extents of the unittest
+  // executable are consistent and they match with the size of the file.
+  const string kFilename = "/proc/self/exe";
+  const off_t kBlockSize = 4096;
+  
+  vector<Extent> extents;
+  
+  ASSERT_TRUE(ExtentsForFileFibmap(kFilename, &extents));
+  
+  EXPECT_FALSE(extents.empty());
+  set<uint64> blocks;
+  
+  for (vector<Extent>::const_iterator it = extents.begin();
+       it != extents.end(); ++it) {
+    for (uint64 block = it->start_block();
+         block < it->start_block() + it->num_blocks();
+         block++) {
+      EXPECT_FALSE(utils::SetContainsKey(blocks, block));
+      blocks.insert(block);
+    }
+  }
+  
+  struct stat stbuf;
+  EXPECT_EQ(0, stat(kFilename.c_str(), &stbuf));
+  EXPECT_EQ(blocks.size(), (stbuf.st_size + kBlockSize - 1)/kBlockSize);
+}
+
+}  // namespace chromeos_update_engine