Merge changes I72cf6f52,I9620e5b4

* changes:
  libsnapshot: Fix crash in cow writer test due to missing ASSERT.
  libsnapshot: Improve low space tests.
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
index 3932fad..56b48f0 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_writer.cpp
@@ -298,13 +298,12 @@
         return false;
     }
 
-    bool ret = OpenForWrite();
-
-    if (ret) {
-        InitWorkers();
+    if (!OpenForWrite()) {
+        return false;
     }
 
-    return ret;
+    InitWorkers();
+    return true;
 }
 
 bool CowWriter::InitializeAppend(android::base::unique_fd&& fd, uint64_t label) {
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 4014380..13314da 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -2669,44 +2669,46 @@
                                     "Merge"s;
                          });
 
-// Test behavior of ImageManager::Create on low space scenario. These tests assumes image manager
-// uses /data as backup device.
-class ImageManagerTest : public SnapshotTest, public WithParamInterface<uint64_t> {
+class ImageManagerTest : public SnapshotTest {
   protected:
     void SetUp() override {
         SKIP_IF_NON_VIRTUAL_AB();
         SnapshotTest::SetUp();
-        userdata_ = std::make_unique<LowSpaceUserdata>();
-        ASSERT_TRUE(userdata_->Init(GetParam()));
     }
     void TearDown() override {
         RETURN_IF_NON_VIRTUAL_AB();
-
+        CleanUp();
+    }
+    void CleanUp() {
         EXPECT_TRUE(!image_manager_->BackingImageExists(kImageName) ||
                     image_manager_->DeleteBackingImage(kImageName));
     }
+
     static constexpr const char* kImageName = "my_image";
-    std::unique_ptr<LowSpaceUserdata> userdata_;
 };
 
-TEST_P(ImageManagerTest, CreateImageNoSpace) {
-    uint64_t to_allocate = userdata_->free_space() + userdata_->bsize();
-    auto res = image_manager_->CreateBackingImage(kImageName, to_allocate,
-                                                  IImageManager::CREATE_IMAGE_DEFAULT);
-    ASSERT_FALSE(res) << "Should not be able to create image with size = " << to_allocate
-                      << " bytes because only " << userdata_->free_space() << " bytes are free";
-    ASSERT_EQ(FiemapStatus::ErrorCode::NO_SPACE, res.error_code()) << res.string();
-}
-
-std::vector<uint64_t> ImageManagerTestParams() {
-    std::vector<uint64_t> ret;
+TEST_F(ImageManagerTest, CreateImageNoSpace) {
+    bool at_least_one_failure = false;
     for (uint64_t size = 1_MiB; size <= 512_MiB; size *= 2) {
-        ret.push_back(size);
-    }
-    return ret;
-}
+        auto userdata = std::make_unique<LowSpaceUserdata>();
+        ASSERT_TRUE(userdata->Init(size));
 
-INSTANTIATE_TEST_SUITE_P(ImageManagerTest, ImageManagerTest, ValuesIn(ImageManagerTestParams()));
+        uint64_t to_allocate = userdata->free_space() + userdata->bsize();
+
+        auto res = image_manager_->CreateBackingImage(kImageName, to_allocate,
+                                                      IImageManager::CREATE_IMAGE_DEFAULT);
+        if (!res) {
+            at_least_one_failure = true;
+        } else {
+            ASSERT_EQ(res.error_code(), FiemapStatus::ErrorCode::NO_SPACE) << res.string();
+        }
+
+        CleanUp();
+    }
+
+    ASSERT_TRUE(at_least_one_failure)
+            << "We should have failed to allocate at least one over-sized image";
+}
 
 bool Mkdir(const std::string& path) {
     if (mkdir(path.c_str(), 0700) && errno != EEXIST) {
diff --git a/fs_mgr/libsnapshot/snapshot_writer_test.cpp b/fs_mgr/libsnapshot/snapshot_writer_test.cpp
index da48eb9..a03632b 100644
--- a/fs_mgr/libsnapshot/snapshot_writer_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_writer_test.cpp
@@ -33,8 +33,8 @@
     TemporaryFile cow_device_file{};
     android::snapshot::CowOptions options{.block_size = BLOCK_SIZE};
     android::snapshot::CompressedSnapshotWriter snapshot_writer{options};
-    snapshot_writer.SetCowDevice(android::base::unique_fd{cow_device_file.fd});
-    snapshot_writer.Initialize();
+    ASSERT_TRUE(snapshot_writer.SetCowDevice(android::base::unique_fd{cow_device_file.fd}));
+    ASSERT_TRUE(snapshot_writer.Initialize());
     std::vector<unsigned char> buffer;
     buffer.resize(BLOCK_SIZE);
     std::fill(buffer.begin(), buffer.end(), 123);
diff --git a/fs_mgr/libsnapshot/test_helpers.cpp b/fs_mgr/libsnapshot/test_helpers.cpp
index b05123a..9f1d676 100644
--- a/fs_mgr/libsnapshot/test_helpers.cpp
+++ b/fs_mgr/libsnapshot/test_helpers.cpp
@@ -227,7 +227,7 @@
         return AssertionFailure() << "Temp file allocated to " << big_file_->path << ", not in "
                                   << kUserDataDevice;
     }
-    uint64_t next_consume = std::min(available_space_ - max_free_space,
+    uint64_t next_consume = std::min(std::max(available_space_, max_free_space) - max_free_space,
                                      (uint64_t)std::numeric_limits<off_t>::max());
     off_t allocated = 0;
     while (next_consume > 0 && free_space_ > max_free_space) {