tests: Add unittest.skipIf() wrapper that works on Python 2.6

Author: bgilbert

tests/__init__.py

@@ -17,7 +17,32 @@
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 
+from functools import wraps
 import os
+import unittest
+
+try:
+    import openslide._convert as _
+    have_optimizations = True
+except ImportError:
+    have_optimizations = False
+
 
 def file_path(name):
     return os.path.join(os.path.dirname(__file__), name)
+
+
+def skip_if(condition, reason):
+    if hasattr(unittest, 'skipIf'):
+        # Python >= 2.7
+        return unittest.skipIf(condition, reason)
+    else:
+        # Python 2.6
+        def decorator(f):
+            @wraps(f)
+            def wrapper(*args, **kwargs):
+                if condition:
+                    return
+                return f(*args, **kwargs)
+            return wrapper
+        return decorator

tests/test_openslide.py

@@ -23,7 +23,7 @@
 import re
 import unittest
 
-from . import file_path
+from . import file_path, have_optimizations, skip_if
 
 # Tests should be written to be compatible with Python 2.6 unittest.
 
@@ -125,12 +125,8 @@ def test_read_region_2GB(self):
                 self.osr.read_region((1000, 1000), 0, (32768, 16384)).size,
                 (32768, 16384))
 
+    @skip_if(have_optimizations, 'only relevant --without-performance')
     def test_read_region_2GB_width(self):
-        try:
-            import openslide._convert
-            return
-        except ImportError:
-            pass
         self.assertRaises(ValueError,
                 lambda: self.osr.read_region((1000, 1000), 0, (1 << 29, 1)))