Fix tests on cray (spack#4298)

* Check for CRAYPE_VERSION instead of path

Architecture tests would fail on Cray since it would not find
the expected path. To make the test correctly work on Cray search
for the CRAYPE version instead.

* Catch SystemExit error in case flake8 not in path

On shared systems having flake8 can involve starting own virtual env.
Skip the test if no flake8 is found to avoid failure reporting.

* Add compatibility to 1.5 svnadmin create

The flag added is needed to correctly create svn repos on NERSC systems.
This could be unnecessary for other sites. I'd like to see others
test before this change gets merged.

lib/spack/spack/test/architecture.py

@@ -58,7 +58,7 @@ def test_dict_functions_for_architecture():
 
 def test_platform():
         output_platform_class = spack.architecture.real_platform()
-        if os.path.exists('/opt/cray/craype'):
+        if os.environ.get('CRAYPE_VERSION') is not None:
             my_platform_class = Cray()
         elif os.path.exists('/bgsys'):
             my_platform_class = Bgq()

lib/spack/spack/test/cmd/flake8.py

@@ -87,10 +87,7 @@ def test_flake8(parser, flake8_package):
     # Otherwise, the unit tests would fail every time
     # the flake8 tests fail
     args = parser.parse_args([flake8_package])
-
     flake8(parser, args)
-
     # Get even more coverage
     args = parser.parse_args(['--output', '--root-relative', flake8_package])
-
     flake8(parser, args)

lib/spack/spack/test/conftest.py

@@ -474,7 +474,9 @@ def mock_svn_repository():
     url = 'file://' + str(repodir)
     # Initialize the repository
     current = repodir.chdir()
-    svnadmin('create', str(repodir))
+    # NOTE: Adding --pre-1.5-compatible works for NERSC
+    # Unknown if this is also an issue at other sites.
+    svnadmin('create', '--pre-1.5-compatible', str(repodir))
 
     # Import a structure (first commit)
     r0_file = 'r0_file'