message: In tests/unit/makefile, always use the full path to the source
  files - this is needed as a workaround for an issue in Coveralls
  when run in Travis CI.
diff: @@ -46,9 +46,11 @@ all: $(UNIT_TESTS)
  unit_tests: $(OBJECT_FILES) $(MFEM_LIB_FILE) $(CONFIG_MK) $(DATA_DIR)
  $(CCC) $(OBJECT_FILES) $(INCLUDES) $(MFEM_LIBS) -o $(@)
  +# Note: in this rule, we always use the full path to the source file as a
  +# workaround for an issue with coveralls.
  $(OBJECT_FILES): %.o: $(SRC)%.cpp $(HEADER_FILES) $(CONFIG_MK)
  @mkdir -p $(@D)
  - $(CCC) -c $(<) $(INCLUDES) -o $(@)
  + $(CCC) -c $(abspath $(<)) $(INCLUDES) -o $(@)
  $(DATA_DIR):
  ln -s $(SRC)$(DATA_DIR) .
  