unwindstack: add some perfunctory MemoryOffline tests.

Add some tests for the behavior of MemoryOffline.

Test: libunwindstack_test 32/64 on hikey960
Change-Id: Ib65a0fe5347b86062ffeaf0adaf9af57066edb76

libunwindstack/Android.bp

@@ -136,6 +136,7 @@ cc_test {
         "tests/MemoryFake.cpp",
         "tests/MemoryFileTest.cpp",
         "tests/MemoryLocalTest.cpp",
+        "tests/MemoryOfflineTest.cpp",
         "tests/MemoryRangeTest.cpp",
         "tests/MemoryRemoteTest.cpp",
         "tests/MemoryTest.cpp",

libunwindstack/tests/MemoryOfflineTest.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed 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 <vector>
+
+#include <gtest/gtest.h>
+
+#include <android-base/file.h>
+#include <android-base/test_utils.h>
+#include <unwindstack/Memory.h>
+
+namespace unwindstack {
+
+class MemoryOfflineTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    for (size_t i = 0; i < 1024; ++i) {
+      data.push_back(i & 0xff);
+    }
+
+    ASSERT_TRUE(android::base::WriteFully(temp_file.fd, &offset, sizeof(offset)));
+    ASSERT_TRUE(android::base::WriteFully(temp_file.fd, data.data(), data.size()));
+
+    memory = std::make_unique<MemoryOffline>();
+    ASSERT_TRUE(memory != nullptr);
+
+    ASSERT_TRUE(memory->Init(temp_file.path, 0));
+  }
+
+  TemporaryFile temp_file;
+  uint64_t offset = 4096;
+  std::vector<char> data;
+  std::unique_ptr<MemoryOffline> memory;
+};
+
+TEST_F(MemoryOfflineTest, read_boundaries) {
+  char buf = '\0';
+  ASSERT_EQ(0U, memory->Read(offset - 1, &buf, 1));
+  ASSERT_EQ(0U, memory->Read(offset + data.size(), &buf, 1));
+  ASSERT_EQ(1U, memory->Read(offset, &buf, 1));
+  ASSERT_EQ(buf, data.front());
+  ASSERT_EQ(1U, memory->Read(offset + data.size() - 1, &buf, 1));
+  ASSERT_EQ(buf, data.back());
+}
+
+TEST_F(MemoryOfflineTest, read_values) {
+  std::vector<char> buf;
+  buf.resize(2 * data.size());
+  ASSERT_EQ(data.size(), memory->Read(offset, buf.data(), buf.size()));
+  buf.resize(data.size());
+  ASSERT_EQ(buf, data);
+}
+
+}  // namespace unwindstack