[lldb-dap] Setup DAP for unit testing.

This is a very simple case that currently only validates we can create a DAP instance and send a message over the transport layer. More in-depth tests will require additional helpers and possibly refactors of DAP to make it more testable, however this is some ground work to have basic support for unit tests.

Author: ashgti

lldb/tools/lldb-dap/DAP.h

@@ -226,7 +226,8 @@ struct DAP {
   /// \param[in] default_repl_mode
   ///     Default repl mode behavior, as configured by the binary.
   /// \param[in] pre_init_commands
-  ///     LLDB commands to execute as soon as the debugger instance is allocaed.
+  ///     LLDB commands to execute as soon as the debugger instance is
+  ///     allocated.
   /// \param[in] transport
   ///     Transport for this debug session.
   DAP(Log *log, const ReplMode default_repl_mode,

lldb/unittests/DAP/CMakeLists.txt

@@ -3,6 +3,7 @@ add_lldb_unittest(DAPTests
   LLDBUtilsTest.cpp
   TransportTest.cpp
   ProtocolTypesTest.cpp
+  DAPTest.cpp
 
   LINK_LIBS
     lldbDAP

lldb/unittests/DAP/DAPTest.cpp

@@ -0,0 +1,63 @@
+//===-- DAPTest.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 "DAP.h"
+#include "Protocol/ProtocolBase.h"
+#include "Transport.h"
+#include "lldb/Host/File.h"
+#include "lldb/Host/Pipe.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+#include <chrono>
+#include <memory>
+#include <optional>
+
+using namespace llvm;
+using namespace lldb;
+using namespace lldb_dap;
+using namespace lldb_dap::protocol;
+using lldb_private::File;
+using lldb_private::NativeFile;
+using lldb_private::Pipe;
+
+class DAPTest : public testing::Test {
+protected:
+  Pipe input;
+  Pipe output;
+  std::unique_ptr<Transport> toDAP;
+  std::unique_ptr<Transport> fromDAP;
+
+  void SetUp() override {
+    ASSERT_THAT_ERROR(input.CreateNew(false).ToError(), Succeeded());
+    ASSERT_THAT_ERROR(output.CreateNew(false).ToError(), Succeeded());
+    toDAP = std::make_unique<Transport>(
+        "toDAP", nullptr,
+        std::make_shared<NativeFile>(input.GetReadFileDescriptor(),
+                                     File::eOpenOptionReadOnly,
+                                     NativeFile::Unowned),
+        std::make_shared<NativeFile>(output.GetWriteFileDescriptor(),
+                                     File::eOpenOptionWriteOnly,
+                                     NativeFile::Unowned));
+    fromDAP = std::make_unique<Transport>(
+        "fromDAP", nullptr,
+        std::make_shared<NativeFile>(output.GetReadFileDescriptor(),
+                                     File::eOpenOptionReadOnly,
+                                     NativeFile::Unowned),
+        std::make_shared<NativeFile>(input.GetWriteFileDescriptor(),
+                                     File::eOpenOptionWriteOnly,
+                                     NativeFile::Unowned));
+  }
+};
+
+TEST_F(DAPTest, SendProtocolMessages) {
+  DAP dap{nullptr, ReplMode::Auto, {}, *toDAP};
+  dap.Send(Event{"my-event", std::nullopt});
+  ASSERT_THAT_EXPECTED(fromDAP->Read(std::chrono::milliseconds(1)),
+                       HasValue(testing::VariantWith<Event>(testing::FieldsAre(
+                           /*event=*/"my-event", /*body=*/std::nullopt))));
+}