fix #25 pip install failed but build success

Author: lidong

zipapps/ensure_zipapps.py.template

@@ -186,7 +186,7 @@ def prepare_path():
                     os.chdir(_cache_folder_path_str)
                     try:
                         pip_main = get_pip_main(ensurepip_root=lazy_pip_dir_str)
-                        pip_main(_pip_args)
+                        assert pip_main(_pip_args) == 0, 'pip install failed'
                     finally:
                         os.chdir(cwd)
                     # avoid duplicated installation

zipapps/main.py

@@ -397,7 +397,7 @@ def pip_install(self):
             target = str(self._cache_path.absolute())
         _pip_args = ['install', '--target', target] + self.pip_args
         pip_main = get_pip_main()
-        pip_main(_pip_args)
+        assert pip_main(_pip_args) == 0, 'pip install failed'
         self.clean_pip_pycache()
 
     def clean_pip_pycache(self):