[clang] [unittest] Add a test for Generic_GCC::GCCVersion::Parse (#69078)

This adds actual test cases for all the cases that are listed in a code
comment in the implementation of this function; having such test
coverage eases doing further modifications to the function.

Author: mstorsjo

clang/unittests/Driver/CMakeLists.txt

@@ -9,6 +9,7 @@ set(LLVM_LINK_COMPONENTS
 add_clang_unittest(ClangDriverTests
   DistroTest.cpp
   DXCModeTest.cpp
+  GCCVersionTest.cpp
   ToolChainTest.cpp
   ModuleCacheTest.cpp
   MultilibBuilderTest.cpp

clang/unittests/Driver/GCCVersionTest.cpp

@@ -0,0 +1,52 @@
+//===- unittests/Driver/GCCVersionTest.cpp --- GCCVersion parser tests ----===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Unit tests for Generic_GCC::GCCVersion
+//
+//===----------------------------------------------------------------------===//
+
+#include "../../lib/Driver/ToolChains/Gnu.h"
+#include "gtest/gtest.h"
+
+using namespace clang;
+using namespace clang::driver;
+
+namespace {
+
+struct VersionParseTest {
+  std::string Text;
+
+  int Major, Minor, Patch;
+  std::string MajorStr, MinorStr, PatchSuffix;
+};
+
+const VersionParseTest TestCases[] = {
+    {"5", 5, -1, -1, "5", "", ""},
+    {"4.4", 4, 4, -1, "4", "4", ""},
+    {"4.4-patched", 4, 4, -1, "4", "4", "-patched"},
+    {"4.4.0", 4, 4, 0, "4", "4", ""},
+    {"4.4.x", 4, 4, -1, "4", "4", ""},
+    {"4.4.2-rc4", 4, 4, 2, "4", "4", "-rc4"},
+    {"4.4.x-patched", 4, 4, -1, "4", "4", ""},
+    {"not-a-version", -1, -1, -1, "", "", ""},
+};
+
+TEST(GCCVersionTest, Parse) {
+  for (const auto &TC : TestCases) {
+    auto V = toolchains::Generic_GCC::GCCVersion::Parse(TC.Text);
+    EXPECT_EQ(V.Text, TC.Text);
+    EXPECT_EQ(V.Major, TC.Major);
+    EXPECT_EQ(V.Minor, TC.Minor);
+    EXPECT_EQ(V.Patch, TC.Patch);
+    EXPECT_EQ(V.MajorStr, TC.MajorStr);
+    EXPECT_EQ(V.MinorStr, TC.MinorStr);
+    EXPECT_EQ(V.PatchSuffix, TC.PatchSuffix);
+  }
+}
+
+} // end anonymous namespace