skip sympy tests if sympy not installed

IPython/extensions/sympy_printing.py

@@ -15,13 +15,19 b' Authors:'
 #-----------------------------------------------------------------------------
 
 from IPython.lib.latextools import latex_to_png
+from IPython.testing import decorators as dec
+
+try:
+    from sympy import pretty, latex
+except ImportError:
+    pass
 
-from sympy import pretty, latex
 
 #-----------------------------------------------------------------------------
 # Definitions of magic functions for use with IPython
 #-----------------------------------------------------------------------------
 
[e-mail]_not_sympy
 def print_basic_unicode(o, p, cycle):
     """A function to pretty print sympy Basic objects."""
     if cycle:
@@ -32,6 +38,7 b' def print_basic_unicode(o, p, cycle):'
     p.text(out)
 
 
[e-mail]_not_sympy
 def print_png(o):
     """A funciton to display sympy expression using LaTex -> PNG."""
     s = latex(o, mode='inline')
@@ -44,7 +51,7 b' def print_png(o):'
 
 _loaded = False
 
-
[e-mail]_not_sympy
 def load_ipython_extension(ip):
     """Load the extension in IPython."""
     global _loaded

IPython/testing/decorators.py

@@ -274,19 +274,19 b' def onlyif(condition, msg):'
 
 #-----------------------------------------------------------------------------
 # Utility functions for decorators
-def numpy_not_available():
-    """Can numpy be imported?  Returns true if numpy does NOT import.
+def module_not_available(module):
+    """Can module be imported?  Returns true if module does NOT import.
 
-    This is used to make a decorator to skip tests that require numpy to be
+    This is used to make a decorator to skip tests that require module to be
     available, but delay the 'import numpy' to test execution time.
     """
     try:
-        import numpy
-        np_not_avail = False
+        mod = __import__(module)
+        mod_not_avail = False
     except ImportError:
-        np_not_avail = True
+        mod_not_avail = True
 
-    return np_not_avail
+    yield mod_not_avail
 
 #-----------------------------------------------------------------------------
 # Decorators for public use
@@ -315,9 +315,11 b" skip_if_not_osx = skipif(sys.platform != 'darwin',"
                          "This test only runs under OSX")
 
 # Other skip decorators
-skipif_not_numpy = skipif(numpy_not_available,"This test requires numpy")
+skipif_not_numpy = skipif(module_not_available('numpy'),"This test requires numpy")
 
-skip_known_failure = skip('This test is known to fail')
+skipif_not_sympy = skipif(module_not_available('sympy'),"This test requires sympy")
+
+skip_known_failure = knownfailureif(True,'This test is known to fail')
 
 # A null 'decorator', useful to make more readable code that needs to pick
 # between different decorators based on OS or other conditions