[lldb-dap] Add unit test for FifoFiles (#140480)

Author: JDevlieghere

lldb/unittests/DAP/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_lldb_unittest(DAPTests
   DAPTest.cpp
+  FifoFilesTest.cpp
   Handler/DisconnectTest.cpp
   JSONUtilsTest.cpp
   LLDBUtilsTest.cpp

lldb/unittests/DAP/FifoFilesTest.cpp

@@ -0,0 +1,102 @@
+//===-- FifoFilesTest.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "FifoFiles.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+#include <chrono>
+#include <thread>
+
+using namespace lldb_dap;
+using namespace llvm;
+
+namespace {
+
+std::string MakeTempFifoPath() {
+  llvm::SmallString<128> temp_path;
+  llvm::sys::fs::createUniquePath("lldb-dap-fifo-%%%%%%", temp_path,
+                                  /*MakeAbsolute=*/true);
+  return temp_path.str().str();
+}
+
+} // namespace
+
+TEST(FifoFilesTest, CreateAndDestroyFifoFile) {
+  std::string fifo_path = MakeTempFifoPath();
+  auto fifo = CreateFifoFile(fifo_path);
+  EXPECT_THAT_EXPECTED(fifo, llvm::Succeeded());
+
+  // File should exist.
+  EXPECT_TRUE(llvm::sys::fs::exists(fifo_path));
+
+  // Destructor should remove the file.
+  fifo->reset();
+  EXPECT_FALSE(llvm::sys::fs::exists(fifo_path));
+}
+
+TEST(FifoFilesTest, SendAndReceiveJSON) {
+  std::string fifo_path = MakeTempFifoPath();
+  auto fifo = CreateFifoFile(fifo_path);
+  EXPECT_THAT_EXPECTED(fifo, llvm::Succeeded());
+
+  FifoFileIO writer(fifo_path, "writer");
+  FifoFileIO reader(fifo_path, "reader");
+
+  llvm::json::Object obj;
+  obj["foo"] = "bar";
+  obj["num"] = 42;
+
+  // Writer thread.
+  std::thread writer_thread([&]() {
+    EXPECT_THAT_ERROR(writer.SendJSON(llvm::json::Value(std::move(obj)),
+                                      std::chrono::milliseconds(500)),
+                      llvm::Succeeded());
+  });
+
+  // Reader thread.
+  std::thread reader_thread([&]() {
+    auto result = reader.ReadJSON(std::chrono::milliseconds(500));
+    EXPECT_THAT_EXPECTED(result, llvm::Succeeded());
+    auto *read_obj = result->getAsObject();
+
+    ASSERT_NE(read_obj, nullptr);
+    EXPECT_EQ((*read_obj)["foo"].getAsString(), "bar");
+    EXPECT_EQ((*read_obj)["num"].getAsInteger(), 42);
+  });
+
+  writer_thread.join();
+  reader_thread.join();
+}
+
+TEST(FifoFilesTest, ReadTimeout) {
+  std::string fifo_path = MakeTempFifoPath();
+  auto fifo = CreateFifoFile(fifo_path);
+  EXPECT_THAT_EXPECTED(fifo, llvm::Succeeded());
+
+  FifoFileIO reader(fifo_path, "reader");
+
+  // No writer, should timeout.
+  auto result = reader.ReadJSON(std::chrono::milliseconds(100));
+  EXPECT_THAT_EXPECTED(result, llvm::Failed());
+}
+
+TEST(FifoFilesTest, WriteTimeout) {
+  std::string fifo_path = MakeTempFifoPath();
+  auto fifo = CreateFifoFile(fifo_path);
+  EXPECT_THAT_EXPECTED(fifo, llvm::Succeeded());
+
+  FifoFileIO writer(fifo_path, "writer");
+
+  // No reader, should timeout.
+  llvm::json::Object obj;
+  obj["foo"] = "bar";
+  EXPECT_THAT_ERROR(writer.SendJSON(llvm::json::Value(std::move(obj)),
+                                    std::chrono::milliseconds(100)),
+                    llvm::Failed());
+}