Fix help description of the Makefile.

Makefile

@@ -29,13 +29,15 @@ help:
 	@echo   all: build kernel only.
 	@echo   help: show this help message.
 	@echo   doc: build the API documents.
-	@echo   build-pack: build Pyslvs executable file.
+	@echo   pack: build Pyslvs executable file.
 	@echo   build: build kernel only.
 	@echo   install: install Pyslvs by setuptools.
 	@echo   uninstall: uninstall Pyslvs by pip.
-	@echo   clean-pack: clean up executable file and PyInstaller items,
-	@echo          but not to delete kernel binary files.
+	@echo   test: run kernel unittest.
+	@echo   test-pack: run pack self-check.
 	@echo   clean: clean up kernel binary files.
+	@echo   clean-pack: clean up executable file and PyInstaller items,
+	@echo               but not to delete kernel binary files.
 	@echo   clean-all: clean every binary files and executable file.
 
 doc: build