tests: move system tests into a package (#51)

Prep for factoring out e.g. signing tests into separate modules. Port of googleapis/google-cloud-python#9777 into new reposiory.

Author: tseaver

tests/system.py renamed to tests/system/test_system.py

@@ -40,6 +40,8 @@
 
 
 USER_PROJECT = os.environ.get("GOOGLE_CLOUD_TESTS_USER_PROJECT")
+DIRNAME = os.path.realpath(os.path.dirname(__file__))
+DATA_DIRNAME = os.path.abspath(os.path.join(DIRNAME, "..", "data"))
 
 
 def _bad_copy(bad_request):
@@ -451,11 +453,10 @@ def test_bucket_get_blob_with_user_project(self):
 
 class TestStorageFiles(unittest.TestCase):
 
- DIRNAME = os.path.realpath(os.path.dirname(__file__))
  FILES = {
- "logo": {"path": DIRNAME + "/data/CloudPlatform_128px_Retina.png"},
- "big": {"path": DIRNAME + "/data/five-point-one-mb-file.zip"},
- "simple": {"path": DIRNAME + "/data/simple.txt"},
+ "logo": {"path": DATA_DIRNAME + "/CloudPlatform_128px_Retina.png"},
+ "big": {"path": DATA_DIRNAME + "/five-point-one-mb-file.zip"},
+ "simple": {"path": DATA_DIRNAME + "/simple.txt"},
  }
 
  @classmethod