Fix Ext2FilesystemTest unittests on Brillo.

The Ext2FilesystemTest tests use a set of pre-generated filesystems
stored in sample_images.tar.bz2 and attempt to parse those. This patch
installs the used filesystems in the same directory as the Chrome OS
test environment would generate those files, relative to the unittest
program executed: in a gen/ subdirectory.

Also, an empty filesystem that was previously created from the unittests
is now pre-generated.

The update_engine_unittests program now depends on those modules being
installed and those unittests pass.

Bug: 26955860
TEST=/data/nativetest/update_engine_unittests/update_engine_unittests --gtest_filter=Ext2FilesystemTest.*

Change-Id: I40082e328cec89a7ef4f06d3b8125a953b29efad

1 files changed, 10 insertions, 21 deletions

diff --git a/payload_generator/ext2_filesystem_unittest.cc b/payload_generator/ext2_filesystem_unittest.cc
index 13620275..f7d25da0 100644
--- a/payload_generator/ext2_filesystem_unittest.cc
+++ b/payload_generator/ext2_filesystem_unittest.cc
@@ -34,7 +34,6 @@
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_generator/extent_utils.h"
 
-using chromeos_update_engine::test_utils::System;
 using std::map;
 using std::set;
 using std::string;
@@ -59,24 +58,13 @@ void ExpectBlocksInRange(const vector<Extent>& extents, uint64_t total_blocks) {
 
 }  // namespace
 
-
-class Ext2FilesystemTest : public ::testing::Test {
- protected:
-  void SetUp() override {
-    ASSERT_TRUE(utils::MakeTempFile("Ext2FilesystemTest-XXXXXX",
-                                    &fs_filename_, nullptr));
-    ASSERT_EQ(0, truncate(fs_filename_.c_str(), kDefaultFilesystemSize));
-  }
-
-  void TearDown() override {
-    unlink(fs_filename_.c_str());
-  }
-
-  string fs_filename_;
-};
+class Ext2FilesystemTest : public ::testing::Test {};
 
 TEST_F(Ext2FilesystemTest, InvalidFilesystem) {
-  unique_ptr<Ext2Filesystem> fs = Ext2Filesystem::CreateFromFile(fs_filename_);
+  test_utils::ScopedTempFile fs_filename_{"Ext2FilesystemTest-XXXXXX"};
+  ASSERT_EQ(0, truncate(fs_filename_.path().c_str(), kDefaultFilesystemSize));
+  unique_ptr<Ext2Filesystem> fs =
+      Ext2Filesystem::CreateFromFile(fs_filename_.path());
   ASSERT_EQ(nullptr, fs.get());
 
   fs = Ext2Filesystem::CreateFromFile("/path/to/invalid/file");
@@ -84,10 +72,9 @@ TEST_F(Ext2FilesystemTest, InvalidFilesystem) {
 }
 
 TEST_F(Ext2FilesystemTest, EmptyFilesystem) {
-  EXPECT_EQ(0, System(base::StringPrintf(
-      "/sbin/mkfs.ext2 -q -b %" PRIuS " -F %s",
-      kDefaultFilesystemBlockSize, fs_filename_.c_str())));
-  unique_ptr<Ext2Filesystem> fs = Ext2Filesystem::CreateFromFile(fs_filename_);
+  base::FilePath path =
+      test_utils::GetBuildArtifactsPath().Append("gen/disk_ext2_4k_empty.img");
+  unique_ptr<Ext2Filesystem> fs = Ext2Filesystem::CreateFromFile(path.value());
 
   ASSERT_NE(nullptr, fs.get());
   EXPECT_EQ(kDefaultFilesystemBlockCount, fs->GetBlockCount());
@@ -194,6 +181,7 @@ TEST_F(Ext2FilesystemTest, LoadSettingsFailsTest) {
   base::FilePath path = test_utils::GetBuildArtifactsPath().Append(
       "gen/disk_ext2_1k.img");
   unique_ptr<Ext2Filesystem> fs = Ext2Filesystem::CreateFromFile(path.value());
+  ASSERT_NE(nullptr, fs.get());
 
   brillo::KeyValueStore store;
   // disk_ext2_1k.img doesn't have the /etc/update_engine.conf file.
@@ -204,6 +192,7 @@ TEST_F(Ext2FilesystemTest, LoadSettingsWorksTest) {
   base::FilePath path = test_utils::GetBuildArtifactsPath().Append(
       "gen/disk_ext2_ue_settings.img");
   unique_ptr<Ext2Filesystem> fs = Ext2Filesystem::CreateFromFile(path.value());
+  ASSERT_NE(nullptr, fs.get());
 
   brillo::KeyValueStore store;
   EXPECT_TRUE(fs->LoadSettings(&store));