Work-around for pytest.mark.skipif() bug

There is a pytest bug that can cause all test classes marked with the
skipif() decorator that inherit a common class to be skipped if one of
the skipif() conditions is True. See:

    pytest-dev/pytest#568

Author: jerrykan

test/test_dates.py

@@ -25,13 +25,13 @@
 from roundup.date import Date, Interval, Range, fixTimeOverflow, \
     get_timezone
 
+# FIX: workaround for a bug in pytest.mark.skipif():
+#   https://github.com/pytest-dev/pytest/issues/568
 try:
     import pytz
-    SKIP_PYTZ = False
+    skip_pytz = lambda func, *args, **kwargs: func
 except ImportError:
-    SKIP_PYTZ = True
-
-skip_pytz = pytest.mark.skipif(SKIP_PYTZ, reason="'pytz' not installed")
+    skip_pytz = pytest.skip("'pytz' not installed")
 
 
 class DateTestCase(unittest.TestCase):

test/test_indexer.py

@@ -30,15 +30,14 @@
 from .test_mysql import mysqlOpener, skip_mysql
 from test_sqlite import sqliteOpener
 
+# FIX: workaround for a bug in pytest.mark.skipif():
+#   https://github.com/pytest-dev/pytest/issues/568
 try:
     import xapian
-    SKIP_XAPIAN = False
+    skip_xapian = lambda func, *args, **kwargs: func
 except ImportError:
-    SKIP_XAPIAN = True
-
-skip_xapian = pytest.mark.skipif(
-    SKIP_XAPIAN,
-    reason="Skipping Xapian indexer tests: 'xapian' not installed")
+    skip_xapian = pytest.skip(
+        "Skipping Xapian indexer tests: 'xapian' not installed")
 
 
 class db:

test/test_mailgw.py

@@ -17,14 +17,13 @@
 
 import pytest
 
+# FIX: workaround for a bug in pytest.mark.skipif():
+#   https://github.com/pytest-dev/pytest/issues/568
 try:
     import pyme, pyme.core
-    SKIP_PGP = False
+    skip_pgp = lambda func, *args, **kwargs: func
 except ImportError:
-    SKIP_PGP = True
-
-skip_pgp = pytest.mark.skipif(
-    SKIP_PGP, reason="Skipping PGP tests: 'pyme' not installed")
+    skip_pgp = pytest.skip("Skipping PGP tests: 'pyme' not installed")
 
 
 from cStringIO import StringIO

test/test_mysql.py

@@ -40,20 +40,17 @@ def nuke_database(self):
         self.module.db_nuke(config)
 
 
+# FIX: workaround for a bug in pytest.mark.skipif():
+#   https://github.com/pytest-dev/pytest/issues/568
 if not have_backend('mysql'):
-    SKIP_MYSQL = True
-    SKIP_MYSQL_REASON = 'Skipping MySQL tests: not enabled'
+    skip_mysql = pytest.skip('Skipping MySQL tests: backend not available')
 else:
     try:
         import MySQLdb
         mysqlOpener.module.db_exists(config)
-        SKIP_MYSQL = False
-        SKIP_MYSQL_REASON = ''
+        skip_mysql = lambda func, *args, **kwargs: func
     except (MySQLdb.MySQLError, DatabaseError) as msg:
-        SKIP_MYSQL = True
-        SKIP_MYSQL_REASON = 'Skipping MySQL tests: %s' % str(msg)
-
-skip_mysql = pytest.mark.skipif(SKIP_MYSQL, reason=SKIP_MYSQL_REASON)
+        skip_mysql = pytest.skip('Skipping MySQL tests: %s' % str(msg))
 
 
 @skip_mysql

test/test_postgresql.py

@@ -26,13 +26,13 @@
 
 from roundup.backends import get_backend, have_backend
 
+# FIX: workaround for a bug in pytest.mark.skipif():
+#   https://github.com/pytest-dev/pytest/issues/568
 if not have_backend('postgresql'):
-    SKIP_POSTGRESQL = True
+    skip_postgresql = pytest.skip(
+        'Skipping PostgreSQL tests: backend not available')
 else:
-    SKIP_POSTGRESQL = False
-
-skip_postgresql = pytest.mark.skipif(
-    SKIP_POSTGRESQL, reason='Skipping PostgreSQL tests: not enabled')
+    skip_postgresql = lambda func, *args, **kwargs: func
 
 
 class postgresqlOpener: