add commoncrypto mark to skip on non-OS X platforms

8 files changed, 90 insertions, 3 deletions

diff --git a/cryptography/hazmat/bindings/openssl/binding.py b/cryptography/hazmat/bindings/openssl/binding.py
index 4f6b99ae..2a1e1184 100644
--- a/cryptography/hazmat/bindings/openssl/binding.py
+++ b/cryptography/hazmat/bindings/openssl/binding.py
@@ -13,7 +13,9 @@
 
 from __future__ import absolute_import, division, print_function
 
-from cryptography.hazmat.bindings.utils import build_ffi
+from cryptography.hazmat.bindings.utils import (
+    build_ffi, binding_available
+)
 
 _OSX_PRE_INCLUDE = """
 #ifdef __APPLE__
@@ -79,3 +81,7 @@ class Binding(object):
         cls.ffi, cls.lib = build_ffi(cls._module_prefix, cls._modules,
                                      _OSX_PRE_INCLUDE, _OSX_POST_INCLUDE,
                                      ["crypto", "ssl"])
+
+    @classmethod
+    def is_available(cls):
+        return binding_available(cls._ensure_ffi_initialized)
diff --git a/cryptography/hazmat/bindings/utils.py b/cryptography/hazmat/bindings/utils.py
index 9e1d3937..9141c155 100644
--- a/cryptography/hazmat/bindings/utils.py
+++ b/cryptography/hazmat/bindings/utils.py
@@ -86,3 +86,11 @@ def build_ffi(module_prefix, modules, pre_include, post_include, libraries):
                     delattr(lib, name)
 
     return ffi, lib
+
+
+def binding_available(initializer):
+    try:
+        initializer()
+        return True
+    except cffi.VerificationError:
+        return False
diff --git a/pytest.ini b/pytest.ini
index 36d4edc4..4bb9b0f9 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -5,3 +5,4 @@ markers =
     cipher: this test requires a backend providing CipherBackend
     hash: this test requires a backend providing HashBackend
     supported: parametrized test requiring only_if and skip_message
+    binding_available: verifies a given binding is available
diff --git a/tests/conftest.py b/tests/conftest.py
index 0ddc3338..3ba2425d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -4,7 +4,9 @@ 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, check_binding_available
+)
 
 
 def pytest_generate_tests(metafunc):
@@ -20,3 +22,4 @@ def pytest_runtest_setup(item):
     check_for_iface("cipher", CipherBackend, item)
     check_for_iface("hash", HashBackend, item)
     check_backend_support(item)
+    check_binding_available(item)
diff --git a/tests/hazmat/bindings/test_bindings.py b/tests/hazmat/bindings/test_bindings.py
new file mode 100644
index 00000000..927bc8a1
--- /dev/null
+++ b/tests/hazmat/bindings/test_bindings.py
@@ -0,0 +1,31 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
+import cffi
+
+from cryptography.hazmat.bindings.utils import binding_available
+from cryptography.hazmat.bindings.openssl.binding import Binding
+
+
+def dummy_initializer():
+    raise cffi.VerificationError
+
+
+def test_binding_available():
+    assert binding_available(Binding._ensure_ffi_initialized) is True
+
+
+def test_binding_unavailable():
+    assert binding_available(dummy_initializer) is False
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index 31f736ab..d1e85058 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -20,3 +20,6 @@ class TestOpenSSL(object):
         assert binding
         assert binding.lib
         assert binding.ffi
+
+    def test_is_available(self):
+        assert Binding.is_available() is True
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e3e53d63..917e87f0 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -14,14 +14,18 @@
 import os
 import textwrap
 
+import cffi
+
 import pretend
 
 import pytest
 
+from cryptography.hazmat.bindings.utils import binding_available
+
 from .utils import (
     load_nist_vectors, load_vectors_from_file, load_cryptrec_vectors,
     load_openssl_vectors, load_hash_vectors, check_for_iface,
-    check_backend_support
+    check_backend_support, check_binding_available
 )
 
 
@@ -72,6 +76,31 @@ def test_check_backend_support_no_backend():
         check_backend_support(item)
 
 
+def test_check_binding_available():
+    from cryptography.hazmat.bindings.openssl.binding import Binding
+    kwargs = pretend.stub(kwargs={"binding": Binding})
+    item = pretend.stub(keywords={"binding_available": kwargs})
+    assert check_binding_available(item) is None
+
+
+def test_check_binding_unavailable():
+    class FakeBinding(object):
+        @classmethod
+        def _ensure_ffi_initialized(cls):
+            raise cffi.VerificationError
+
+        @classmethod
+        def is_available(cls):
+            return binding_available(cls._ensure_ffi_initialized)
+
+    kwargs = pretend.stub(kwargs={"binding": FakeBinding})
+    item = pretend.stub(keywords={"binding_available": kwargs})
+    with pytest.raises(pytest.skip.Exception) as exc_info:
+        check_binding_available(item)
+    assert exc_info.value.args[0] == ("<class 'tests.test_utils.FakeBinding'>"
+                                      " is not available")
+
+
 def test_load_nist_vectors():
     vector_data = textwrap.dedent("""
     # CAVS 11.1
diff --git a/tests/utils.py b/tests/utils.py
index 693a0c8f..6d47a398 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -36,6 +36,12 @@ def check_backend_support(item):
                          "backend")
 
 
+def check_binding_available(item):
+    ba = item.keywords.get("binding_available")
+    if ba and not ba.kwargs["binding"].is_available():
+        pytest.skip("{0} is not available".format(ba.kwargs["binding"]))
+
+
 def load_vectors_from_file(filename, loader):
     base = os.path.join(
         os.path.dirname(__file__), "hazmat", "primitives", "vectors",