Adding code. Closes #0.

test/stack_line_reader_test.cc

@@ -0,0 +1,132 @@
+// Copyright 2017 Google Inc.
+//
+// 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 "internal/stack_line_reader.h"
+#include "filesystem_for_testing.h"
+
+#include "gtest/gtest.h"
+
+namespace cpu_features {
+
+bool operator==(const StringView& a, const StringView& b) {
+  return IsEquals(a, b);
+}
+
+namespace {
+
+std::string ToString(StringView view) { return {view.ptr, view.size}; }
+
+TEST(StackLineReaderTest, Empty) {
+  auto& fs = GetEmptyFilesystem();
+  auto* file = fs.CreateFile("/proc/cpuinfo", "");
+  StackLineReader reader;
+  StackLineReader_Initialize(&reader, file->GetFileDescriptor());
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_TRUE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str(""));
+  }
+}
+
+TEST(StackLineReaderTest, ManySmallLines) {
+  auto& fs = GetEmptyFilesystem();
+  auto* file = fs.CreateFile("/proc/cpuinfo", "a\nb\nc");
+
+  StackLineReader reader;
+  StackLineReader_Initialize(&reader, file->GetFileDescriptor());
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("a"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("b"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_TRUE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("c"));
+  }
+}
+
+TEST(StackLineReaderTest, TruncatedLine) {
+  auto& fs = GetEmptyFilesystem();
+  auto* file = fs.CreateFile("/proc/cpuinfo", R"(First
+Second
+More than 16 characters, this will be truncated.
+last)");
+
+  StackLineReader reader;
+  StackLineReader_Initialize(&reader, file->GetFileDescriptor());
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("First"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("Second"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_FALSE(result.full_line);
+    EXPECT_EQ(result.line, str("More than 16 cha"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_TRUE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str("last"));
+  }
+}
+
+TEST(StackLineReaderTest, TruncatedLines) {
+  auto& fs = GetEmptyFilesystem();
+  auto* file = fs.CreateFile("/proc/cpuinfo", R"(More than 16 characters
+Another line that is too long)");
+
+  StackLineReader reader;
+  StackLineReader_Initialize(&reader, file->GetFileDescriptor());
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_FALSE(result.full_line);
+    EXPECT_EQ(result.line, str("More than 16 cha"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_FALSE(result.eof);
+    EXPECT_FALSE(result.full_line);
+    EXPECT_EQ(result.line, str("Another line tha"));
+  }
+  {
+    const auto result = StackLineReader_NextLine(&reader);
+    EXPECT_TRUE(result.eof);
+    EXPECT_TRUE(result.full_line);
+    EXPECT_EQ(result.line, str(""));
+  }
+}
+
+}  // namespace
+}  // namespace cpu_features