Be more careful when Cython is available but NumPy is not

cassandra/cython_deps.py

@@ -2,4 +2,10 @@ try:
     from cassandra.rowparser import make_recv_results_rows
     HAVE_CYTHON = True
 except ImportError:
-    HAVE_CYTHON = False
+    HAVE_CYTHON = False
+
+try:
+    import numpy
+    HAVE_NUMPY = True
+except ImportError:
+    HAVE_NUMPY = False

cassandra/protocol.py

@@ -40,7 +40,7 @@ from cassandra.cqltypes import (AsciiType, BytesType, BooleanType,
                                 TupleType, lookup_casstype, SimpleDateType,
                                 TimeType, ByteType, ShortType)
 from cassandra.policies import WriteType
-from cassandra.cython_deps import HAVE_CYTHON
+from cassandra.cython_deps import HAVE_CYTHON, HAVE_NUMPY
 from cassandra import util
 
 log = logging.getLogger(__name__)
@@ -1039,14 +1039,17 @@ def cython_protocol_handler(colparser):
 
 if HAVE_CYTHON:
     from cassandra.objparser import ListParser, LazyParser
-    from cassandra.numpyparser import NumpyParser
-
     ProtocolHandler = cython_protocol_handler(ListParser())
     LazyProtocolHandler = cython_protocol_handler(LazyParser())
-    NumpyProtocolHandler = cython_protocol_handler(NumpyParser())
 else:
     # Use Python-based ProtocolHandler
     LazyProtocolHandler = None
+
+
+if HAVE_CYTHON and HAVE_NUMPY:
+    from cassandra.numpyparser import NumpyParser
+    NumpyProtocolHandler = cython_protocol_handler(NumpyParser())
+else:
     NumpyProtocolHandler = None
 
 

tests/unit/cython/utils.py

@@ -1,9 +1,4 @@
-try:
+from cassandra.cython_deps import HAVE_CYTHON, HAVE_NUMPY
-    import tests.unit.cython.dummy_module
-except ImportError:
-    have_cython = False
-else:
-    have_cython = True
 
 try:
     import unittest2 as unittest
@@ -18,10 +13,11 @@ def cyimport(import_path):
     try:
         return __import__(import_path, fromlist=True)
     except ImportError:
-        if have_cython:
+        if HAVE_CYTHON:
             raise
         return None
 
 # @cythontest
 # def test_something(self): ...
-cythontest = unittest.skipUnless(have_cython, 'Cython is not available')
+cythontest = unittest.skipUnless(HAVE_CYTHON, 'Cython is not available')
+numpytest  = unittest.skipUnless(HAVE_CYTHON and HAVE_NUMPY, 'NumPy is not available')