Addresses pytest 5.1.0 failures

package/CHANGELOG

@@ -130,6 +130,8 @@ Deprecations
     method to be used, this is done automatically in run()
 
 Testsuite
+  * Raised minimum pytest version to 3.3.0, warns now uses the `match` 
+    argument instead of `match_expr` (Issue #2329)
   * Add tests for the new water bridge analysis (PR #2087)
 
 11/06/18 richardjgowers

testsuite/MDAnalysisTests/lib/test_util.py

@@ -1861,7 +1861,8 @@ def AlternateUniverse(anything):
                              new_name=new_name,
                              release=release, remove=remove,
                              message=message)
-    with pytest.warns(DeprecationWarning, match_expr="`.+` is deprecated"):
+    # match_expr changed to match (Issue 2329)
+    with pytest.warns(DeprecationWarning, match="`.+` is deprecated"):
         oldfunc(42)
 
     doc = oldfunc.__doc__

testsuite/setup.py

@@ -178,7 +178,7 @@ def run(self):
           },
           install_requires=[
               'MDAnalysis=={0!s}'.format(RELEASE),  # same as this release!
-              'pytest>=3.1.2',
+              'pytest>=3.3.0', # Raised to 3.3.0 due to Issue 2329
               'hypothesis',
               'psutil>=4.0.2',
               'mock>=2.0.0',  # replace with unittest.mock in python 3 only version