Merge branch 'master' into commoncrypto-cipher-backend

* master:
  expand tox backend example
  On OS X at build time compile the CC bindings
  fix docs
  update docs for name attribute
  revert fixture decorator for now, switch to append. no more globals
  docs for explicit backend selection and document name attribute of backend
  modify backend selection to allow multiple backends via comma delimiter
  better name for the variable
  don't mutate _ALL_BACKENDS
  pass posargs via tox so --backend can be used for tox envs
  support --backend as a pytest flag to limit to one backend for testing

1 files changed, 14 insertions, 4 deletions

diff --git a/tests/conftest.py b/tests/conftest.py
index 1d9f96ed..a9acb54a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -5,12 +5,15 @@ from cryptography.hazmat.backends.interfaces import (
     HMACBackend, CipherBackend, HashBackend
 )
 
-from .utils import check_for_iface, check_backend_support
+from .utils import check_for_iface, check_backend_support, select_backends
 
 
-@pytest.fixture(params=_ALL_BACKENDS)
-def backend(request):
-    return request.param
+def pytest_generate_tests(metafunc):
+    names = metafunc.config.getoption("--backend")
+    selected_backends = select_backends(names, _ALL_BACKENDS)
+
+    if "backend" in metafunc.fixturenames:
+        metafunc.parametrize("backend", selected_backends)
 
 
 @pytest.mark.trylast
@@ -19,3 +22,10 @@ def pytest_runtest_setup(item):
     check_for_iface("cipher", CipherBackend, item)
     check_for_iface("hash", HashBackend, item)
     check_backend_support(item)
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--backend", action="store", metavar="NAME",
+        help="Only run tests matching the backend NAME."
+    )