Add more tests

Author: augusto2112

lldb/unittests/Language/CPlusPlus/CPlusPlusLanguageTest.cpp

@@ -410,3 +410,20 @@ TEST(CPlusPlusLanguage, DoesNotMatchCxx) {
   Mangled swiftSymbol("$sS");
   EXPECT_FALSE(CPlusPlusLang->SymbolNameFitsToLanguage(swiftSymbol));
 }
+
+TEST(CPlusPlusLanguage, MatchesCxx) {
+  // Test that a symbol name that is C++ does match C++ (both Itanium and MSVC).
+
+  SubsystemRAII<CPlusPlusLanguage> lang;
+  Language *CPlusPlusLang =
+      Language::FindPlugin(lldb::eLanguageTypeC_plus_plus);
+
+  EXPECT_TRUE(CPlusPlusLang != nullptr);
+
+  Mangled itaniumSymbol("_ZFoo");
+  EXPECT_TRUE(CPlusPlusLang->SymbolNameFitsToLanguage(itaniumSymbol));
+  Mangled itaniumExtensionSymbol("___ZBar");
+  EXPECT_TRUE(CPlusPlusLang->SymbolNameFitsToLanguage(itaniumExtensionSymbol));
+  Mangled msvcSymbol("?Baz");
+  EXPECT_TRUE(CPlusPlusLang->SymbolNameFitsToLanguage(msvcSymbol));
+}