Simplify CMake config and do minor adjustments

for consistency with used coding conventions.

test/CMakeLists.txt

@@ -2,9 +2,13 @@ set(FMT_GMOCK_DIR ../gmock)
 
 include_directories(.. ${FMT_GMOCK_DIR})
 
-if (BUILD_SHARED_LIBS)
-  set(FMT_IMPORT "-DFMT_SHARED")
-endif ()
+# Links target with cppformat and any libraries passed as extra arguments.
+function (target_link_cppformat target)
+  target_link_libraries(${target} cppformat ${ARGN})
+  if (BUILD_SHARED_LIBS)
+    set_target_properties(${target} PROPERTIES COMPILE_FLAGS -DFMT_SHARED)
+  endif ()
+endfunction ()
 
 # We compile Google Test ourselves instead of using pre-compiled libraries.
 # See the Google Test FAQ "Why is it not recommended to install a
@@ -49,8 +53,7 @@ endif ()
 
 set(TEST_MAIN_SRC test-main.cc gtest-extra.cc gtest-extra.h util.cc)
 add_library(test-main STATIC ${TEST_MAIN_SRC})
-set_target_properties(test-main PROPERTIES COMPILE_FLAGS "${FMT_IMPORT}")
-target_link_libraries(test-main cppformat gmock)
+target_link_cppformat(test-main gmock)
 
 # Adds a test.
 # Usage: add_fmt_test(name [CUSTOM_LINK] srcs...)
@@ -59,8 +62,7 @@ function(add_fmt_test name)
   add_executable(${name} ${name}.cc ${add_fmt_test_UNPARSED_ARGUMENTS})
   target_link_libraries(${name} test-main)
   if (NOT add_fmt_test_CUSTOM_LINK)
-    set_target_properties(${name} PROPERTIES COMPILE_FLAGS "${FMT_IMPORT}")
-    target_link_libraries(${name} cppformat)
+    target_link_cppformat(${name})
   endif ()
   add_test(NAME ${name} COMMAND ${name})
 endfunction()