CMake: Add support for non-main.cpp greentea tests

Greentea tests with name other than main.cpp can now be built with CMake
macro using an optional flag.

Author: hazzlim

tools/cmake/mbed_greentea.cmake

@@ -22,39 +22,39 @@ include(${CMAKE_CURRENT_LIST_DIR}/app.cmake)
 
 macro(mbed_greentea_add_test)
     set(options)
-    set(singleValueArgs TEST_NAME)
+    set(singleValueArgs 
+        TEST_NAME
+        TEST_MAIN)
     set(multipleValueArgs
         TEST_INCLUDE_DIRS
         TEST_SOURCES
-        TEST_REQUIRED_LIBS
-    )
+        TEST_REQUIRED_LIBS)
     cmake_parse_arguments(MBED_GREENTEA
         "${options}"
         "${singleValueArgs}"
         "${multipleValueArgs}"
         ${ARGN}
     )
 
-    set(TEST_NAME ${MBED_GREENTEA_TEST_NAME})
-
     add_subdirectory(${MBED_PATH} build)
 
-    add_executable(${TEST_NAME})
-
-    # Explicitly enable BUILD_TESTING until CTest is added to the Greentea client
+    add_executable(${MBED_GREENTEA_TEST_NAME}) # Explicitly enable BUILD_TESTING until CTest is added to the Greentea client
     set(BUILD_TESTING ON)
 
-    mbed_configure_app_target(${TEST_NAME})
+    mbed_configure_app_target(${MBED_GREENTEA_TEST_NAME})
 
-    target_include_directories(${TEST_NAME}
+    target_include_directories(${MBED_GREENTEA_TEST_NAME}
         PRIVATE
             .
             ${MBED_GREENTEA_TEST_INCLUDE_DIRS}
     )
 
-    target_sources(${TEST_NAME}
+    if("${MBED_GREENTEA_TEST_MAIN}" STREQUAL "")
+        set(MBED_GREENTEA_TEST_MAIN main.cpp)
+    endif()
+    target_sources(${MBED_GREENTEA_TEST_NAME}
         PRIVATE
-            main.cpp
+            ${MBED_GREENTEA_TEST_MAIN} 
             ${MBED_GREENTEA_TEST_SOURCES}
     )
 
@@ -71,12 +71,12 @@ macro(mbed_greentea_add_test)
         list(APPEND MBED_GREENTEA_TEST_REQUIRED_LIBS mbed-greentea)
     endif()
 
-    target_link_libraries(${TEST_NAME}
+    target_link_libraries(${MBED_GREENTEA_TEST_NAME}
         PRIVATE
             ${MBED_GREENTEA_TEST_REQUIRED_LIBS}
     )
 
-    mbed_set_post_build(${TEST_NAME})
+    mbed_set_post_build(${MBED_GREENTEA_TEST_NAME})
 
     option(VERBOSE_BUILD "Have a verbose build process")
     if(VERBOSE_BUILD)