clang-tidy module: add test for ostringstream check

Utilities/ClangTidyModule/Tests/CMakeLists.txt

@@ -13,3 +13,4 @@ endfunction()
 add_run_clang_tidy_test(cmake-use-cmstrlen)
 add_run_clang_tidy_test(cmake-use-cmsys-fstream)
 add_run_clang_tidy_test(cmake-use-bespoke-enum-class)
+add_run_clang_tidy_test(cmake-ostringstream-use-cmstrcat)

Utilities/ClangTidyModule/Tests/cmake-ostringstream-use-cmstrcat-stdout.txt

@@ -0,0 +1,6 @@
+cmake-ostringstream-use-cmstrcat.cxx:5:3: warning: use strings and cmStrCat() instead of std::ostringstream [cmake-ostringstream-use-cmstrcat]
+  std::ostringstream test;
+  ^
+cmake-ostringstream-use-cmstrcat.cxx:8:13: warning: use strings and cmStrCat() instead of std::ostringstream [cmake-ostringstream-use-cmstrcat]
+void check2(std::ostringstream& test2)
+            ^

Utilities/ClangTidyModule/Tests/cmake-ostringstream-use-cmstrcat.cxx

@@ -0,0 +1,10 @@
+#include <sstream>
+
+void check()
+{
+  std::ostringstream test;
+}
+
+void check2(std::ostringstream& test2)
+{
+}