Add rule to prevent "GROUP BY <expr>" in tests

Added a new exclusion rule group_by_complex_expression
which disables tests that use "GROUP BY <expr>", which seems
to be not viable for at least two third party dialects.

Change-Id: I47284513382ae93f5a3d12c734b3a44643147c99

2 files changed, 12 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py
index 0b89a4506..b89d149d6 100644
--- a/lib/sqlalchemy/testing/requirements.py
+++ b/lib/sqlalchemy/testing/requirements.py
@@ -206,6 +206,17 @@ class SuiteRequirements(Requirements):
 
         return exclusions.open()
 
+    @property
+    def group_by_complex_expression(self):
+        """target platform supports SQL expressions in GROUP BY
+
+        e.g.
+
+        SELECT x + y AS somelabel FROM table GROUP BY x + y
+
+        """
+
+        return exclusions.open()
 
     @property
     def sane_rowcount(self):
diff --git a/lib/sqlalchemy/testing/suite/test_select.py b/lib/sqlalchemy/testing/suite/test_select.py
index 097214823..df638c140 100644
--- a/lib/sqlalchemy/testing/suite/test_select.py
+++ b/lib/sqlalchemy/testing/suite/test_select.py
@@ -87,6 +87,7 @@ class OrderByLabelTest(fixtures.TablesTest):
             [(7, ), (5, ), (3, )]
         )
 
+    @testing.requires.group_by_complex_expression
     def test_group_by_composed(self):
         table = self.tables.some_table
         expr = (table.c.x + table.c.y).label('lx')