Add format-tests target

cmake/Modules/FindClangFormat.cmake

@@ -0,0 +1,46 @@
+# Find clang-format
+find_program(ClangFormat_EXECUTABLE NAMES clang-format
+                                          clang-format-10.0
+                                          clang-format-9.0
+                                          clang-format-8.0
+                                          clang-format-7.0
+                                          clang-format-6.0
+                                     DOC "clang-format executable")
+mark_as_advanced(ClangFormat_EXECUTABLE)
+
+if(ClangFormat_EXECUTABLE)
+  # find version
+  execute_process(COMMAND ${ClangFormat_EXECUTABLE} --version
+                  OUTPUT_VARIABLE clang_format_version
+                  ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+
+  if(clang_format_version MATCHES "^clang-format version .*")
+    # Arch Linux
+    # clang-format version 10.0.0
+
+    # Ubuntu 18.04 LTS Output
+    # clang-format version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
+    string(REGEX REPLACE "clang-format version ([0-9.]+).*"
+                         "\\1"
+                         ClangFormat_VERSION
+                         "${clang_format_version}")
+  elseif(clang_format_version MATCHES ".*LLVM version .*")
+    # CentOS 7 Output
+    # LLVM (http://llvm.org/):
+    #   LLVM version 3.4.2
+    #   Optimized build.
+    #   Built Nov  1 2018 (15:06:24).
+    #   Default target: x86_64-redhat-linux-gnu
+    #   Host CPU: x86-64
+    string(REGEX REPLACE ".*LLVM version ([0-9.]+).*"
+                         "\\1"
+                         ClangFormat_VERSION
+                         "${clang_format_version}")
+  else()
+    set(ClangFormat_VERSION "0.0")
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(ClangFormat REQUIRED_VARS ClangFormat_EXECUTABLE VERSION_VAR ClangFormat_VERSION)

unittest/CMakeLists.txt

@@ -5,3 +5,13 @@ add_subdirectory(force-styles)
 add_subdirectory(utils)
 
 add_subdirectory(formats)
+
+find_package(ClangFormat)
+
+if(ClangFormat_FOUND)
+  set(UNITTEST_SOURCES)
+  file(GLOB_RECURSE UNITTEST_SOURCES *.cpp *.h)
+  add_custom_target(format-tests
+    COMMAND ${ClangFormat_EXECUTABLE} --verbose -i -style=file ${UNITTEST_SOURCES}
+    DEPENDS ${UNITTEST_SOURCES})
+endif()