Render ExcludeContraint Column as column, not plain string

Fixed bug where autogenerate of :class:`.ExcludeConstraint`
would render a raw quoted name for a Column that has case-sensitive
characters, which when invoked as an inline member of the Table
would produce a stack trace that the quoted name is not found.
An incoming Column object is now rendered as ``sa.column('name')``.

Change-Id: Ic84fc0b0fbaa5816ece1944043cd01a653bfe4ce
Fixes: #478

1 files changed, 58 insertions, 1 deletions

diff --git a/tests/test_postgresql.py b/tests/test_postgresql.py
index e60a02d..ae74c08 100644
--- a/tests/test_postgresql.py
+++ b/tests/test_postgresql.py
@@ -760,11 +760,37 @@ unique=False, """
 
         eq_ignore_whitespace(
             autogenerate.render_op_text(autogen_context, op_obj),
-            "op.create_exclude_constraint('t_excl_x', 't', ('x', '>'), "
+            "op.create_exclude_constraint('t_excl_x', 't', (sa.column('x'), '>'), "
             "where=sa.text(!U'x != 2'), using='gist')"
         )
 
     @config.requirements.fail_before_sqla_100
+    def test_add_exclude_constraint_case_sensitive(self):
+        from sqlalchemy.dialects.postgresql import ExcludeConstraint
+
+        autogen_context = self.autogen_context
+
+        m = MetaData()
+        t = Table('TTAble', m,
+                  Column('XColumn', String),
+                  Column('YColumn', String)
+                  )
+
+        op_obj = ops.AddConstraintOp.from_constraint(ExcludeConstraint(
+            (t.c.XColumn, ">"),
+            where=t.c.XColumn != 2,
+            using="gist",
+            name="t_excl_x"
+        ))
+
+        eq_ignore_whitespace(
+            autogenerate.render_op_text(autogen_context, op_obj),
+            "op.create_exclude_constraint('t_excl_x', 'TTAble', (sa.column('XColumn'), '>'), "
+            "where=sa.text(!U'\"XColumn\" != 2'), using='gist')"
+        )
+
+
+    @config.requirements.fail_before_sqla_100
     def test_inline_exclude_constraint(self):
         from sqlalchemy.dialects.postgresql import ExcludeConstraint
 
@@ -794,6 +820,37 @@ unique=False, """
             ")"
         )
 
+    @config.requirements.fail_before_sqla_100
+    def test_inline_exclude_constraint_case_sensitive(self):
+        from sqlalchemy.dialects.postgresql import ExcludeConstraint
+
+        autogen_context = self.autogen_context
+
+        m = MetaData()
+        t = Table(
+            'TTable', m,
+            Column('XColumn', String),
+            Column('YColumn', String),
+        )
+        ExcludeConstraint(
+            (t.c.XColumn, ">"),
+            using="gist",
+            where='"XColumn" != 2',
+            name="TExclX"
+        )
+
+        op_obj = ops.CreateTableOp.from_table(t)
+
+        eq_ignore_whitespace(
+            autogenerate.render_op_text(autogen_context, op_obj),
+            "op.create_table('TTable',sa.Column('XColumn', sa.String(), "
+            "nullable=True),"
+            "sa.Column('YColumn', sa.String(), nullable=True),"
+            "postgresql.ExcludeConstraint((sa.column('XColumn'), '>'), "
+            "where=sa.text(!U'\"XColumn\" != 2'), using='gist', "
+            "name='TExclX'))"
+        )
+
     @config.requirements.sqlalchemy_09
     def test_json_type(self):
         if config.requirements.sqlalchemy_110.enabled: