fix conditional requests_credssp import (#85)

azure-pipelines.yml

@@ -24,14 +24,22 @@ stages:
       matrix:
         Python27:
           python.version: 2.7
+          credssp: "requests-credssp"
         Python35:
           python.version: 3.5
+          credssp: "requests-credssp"
         Python36:
           python.version: 3.6
+          credssp: "requests-credssp"
         Python37:
           python.version: 3.7
+          credssp: "requests-credssp"
         Python38:
           python.version: 3.8
+          credssp: "requests-credssp"
+        Python38-nocredssp:
+          python.version: 3.8
+          credssp: ""
 
     steps:
     - task: UsePythonVersion@0
@@ -51,7 +59,7 @@ stages:
         python -m pip install --upgrade pip setuptools wheel coverage -c tests/constraints.txt
 
         echo "Installing test requirements"
-        python -m pip install -r requirements-test.txt -c tests/constraints.txt
+        python -m pip install $(credssp) -r requirements-test.txt -c tests/constraints.txt
 
         echo "Installing package"
         python -m pip install . -c tests/constraints.txt
@@ -91,33 +99,47 @@ stages:
         Python27-x86:
           python.version: 2.7
           python.arch: x86
+          credssp: "requests-credssp"
         Python27-x64:
           python.version: 2.7
           python.arch: x64
+          credssp: "requests-credssp"
         Python35-x86:
           python.version: 3.5
           python.arch: x86
+          credssp: "requests-credssp"
         Python35-x64:
           python.version: 3.5
           python.arch: x64
+          credssp: "requests-credssp"
         Python36-x86:
           python.version: 3.6
           python.arch: x86
+          credssp: "requests-credssp"
         Python36-x64:
           python.version: 3.6
           python.arch: x64
+          credssp: "requests-credssp"
         Python37-x86:
           python.version: 3.7
           python.arch: x86
+          credssp: "requests-credssp"
         Python37-x64:
           python.version: 3.7
           python.arch: x64
+          credssp: "requests-credssp"
         Python38-x86:
           python.version: 3.8
           python.arch: x86
+          credssp: "requests-credssp"
         Python38-x64:
           python.version: 3.8
           python.arch: x64
+          credssp: "requests-credssp"
+        Python38-x64-nocredssp:
+          python.version: 3.8
+          python.arch: x64
+          credssp: ""
 
     steps:
     - task: UsePythonVersion@0
@@ -130,7 +152,7 @@ stages:
         python -m pip install --upgrade pip setuptools wheel coverage -c tests/constraints.txt
 
         echo "Installing test requirements"
-        python -m pip install -r requirements-test.txt -c tests/constraints.txt
+        python -m pip install $(credssp) -r requirements-test.txt -c tests/constraints.txt
 
         echo "Installing package"
         python -m pip install . -c tests/constraints.txt

pypsrp/wsman.py

@@ -19,13 +19,17 @@
 from pypsrp.negotiate import HTTPNegotiateAuth
 from pypsrp._utils import to_string, to_unicode, get_hostname
 
-HAS_CREDSSP = True
-CREDSSP_IMP_ERR = None
 try:
     from requests_credssp import HttpCredSSPAuth
 except ImportError as err:  # pragma: no cover
-    HAS_CREDSSP = False
-    CREDSSP_IMP_ERR = err
+    _requests_credssp_import_error = (
+        "Cannot use CredSSP auth as requests-credssp is not installed: %s"
+        % err
+    )
+
+    class HttpCredSSPAuth(object):
+        def __init__(self, *args, **kwargs):
+            raise ImportError(_requests_credssp_import_error)
 
 if sys.version_info[0] == 2 and sys.version_info[1] < 7:  # pragma: no cover
     # ElementTree in Python 2.6 does not support namespaces so we need to use
@@ -882,10 +886,6 @@ def _build_auth_certificate(self, session):
                                            "https/mutual"
 
     def _build_auth_credssp(self, session):
-        if not HAS_CREDSSP:
-            raise ImportError("Cannot use CredSSP auth as requests-credssp is "
-                              "not installed: %s" % str(CREDSSP_IMP_ERR))
-
         if self.username is None:
             raise ValueError("For credssp auth, the username must be "
                              "specified")

requirements-test.txt

@@ -4,5 +4,4 @@ pytest
 pytest-cov
 pytest-mock
 pyyaml
-requests-credssp >= 1.0.0
 xmldiff

tests/constraints.txt

@@ -1,2 +1,3 @@
 # Other constraints
 pytest >= 3.6 ; python_version > "2.7"  # Make sure other Python versions use a newer version of pytest
+requests-credssp >= 1.0.0

tests/test_wsman.py

@@ -19,6 +19,11 @@
 except ImportError:
     from mock import MagicMock
 
+try:
+    import requests_credssp
+except ImportError:
+    requests_credssp = None
+
 if sys.version_info[0] == 2 and sys.version_info[1] < 7:  # pragma: no cover
     # ElementTree in Python 2.6 does not support namespaces so we need to use
     # lxml instead for this version
@@ -27,16 +32,6 @@
     import xml.etree.ElementTree as ET
 
 
-@pytest.fixture('function')
-def reset_imports():
-    # ensure the changes to these globals aren't persisted after each test
-    orig_has_credssp = pypsrp_wsman.HAS_CREDSSP
-    orig_credssp_imp_err = pypsrp_wsman.CREDSSP_IMP_ERR
-    yield None
-    pypsrp_wsman.HAS_CREDSSP = orig_has_credssp
-    pypsrp_wsman.CREDSSP_IMP_ERR = orig_credssp_imp_err
-
-
 class _TransportTest(object):
 
     def __init__(self, expected_action=None):
@@ -684,6 +679,7 @@ def test_set_multiple_options(self):
         assert str(selector_set) == "{'key1': 'value1', 'key2': 'value2'}"
 
 
+
 class TestTransportHTTP(object):
 
     def test_not_supported_auth(self):
@@ -773,26 +769,29 @@ def test_build_certificate(self):
             "http://schemas.dmtf.org/wbem/wsman/1/wsman/secprofile/" \
             "https/mutual"
 
-    def test_build_credssp_not_imported(self, reset_imports):
-        pypsrp_wsman.HAS_CREDSSP = False
-        pypsrp_wsman.CREDSSP_IMP_ERR = "import failed"
-        transport = _TransportHTTP("")
-        with pytest.raises(ImportError) as err:
+    @pytest.mark.skipif(
+        requests_credssp,
+        reason="only raises if requests-credssp is not installed",
+    )
+    def test_build_credssp_not_imported(self):
+        transport = _TransportHTTP("", username="user", password="password")
+        with pytest.raises(
+            ImportError,
+            match=(
+                r"Cannot use CredSSP auth as requests-credssp is not "
+                r"installed: No module named '?requests_credssp'?"
+            ),
+        ):
             transport._build_auth_credssp(None)
-        assert str(err.value) == \
-            "Cannot use CredSSP auth as requests-credssp is not " \
-            "installed: import failed"
 
-    def test_build_credssp_no_username(self, reset_imports):
-        pypsrp_wsman.HAS_CREDSSP = True
+    def test_build_credssp_no_username(self):
         transport = _TransportHTTP("")
         with pytest.raises(ValueError) as err:
             transport._build_auth_credssp(None)
         assert str(err.value) == \
             "For credssp auth, the username must be specified"
 
-    def test_build_credssp_no_password(self, reset_imports):
-        pypsrp_wsman.HAS_CREDSSP = True
+    def test_build_credssp_no_password(self):
         transport = _TransportHTTP("", username="user")
         with pytest.raises(ValueError) as err:
             transport._build_auth_credssp(None)

tox.ini

@@ -1,11 +1,12 @@
 [tox]
-envlist = lint,py27,py35,py36,py37,py38
+envlist = lint,py27,py35,py36,py37,py38-{credssp,}
 skip_missing_interpreters = true
 
 [testenv]
 deps =
     -r{toxinidir}/requirements-test.txt
     -c{toxinidir}/tests/constraints.txt
+    credssp: requests-credssp >= 1.0.0
 commands =
     py.test -v --cov pypspnego --cov-report term-missing
 
@@ -14,4 +15,4 @@ passenv =
 
 [testenv:lint]
 commands =
-    pycodestyle pypsrp --verbose --show-source --statistics
+    pycodestyle pypsrp --verbose --show-source --statistics