Copy whereclause / using in ExcludeConstraint

Fixed bug in Postgresql :class:`.ExcludeConstraint` where the
"whereclause" and "using" parameters would not be copied during an
operation like :meth:`.Table.tometadata`.

Change-Id: I2f704981d4d4862f9c82a50272006fab8becebb6
Fixes: #3900

1 files changed, 24 insertions, 0 deletions

diff --git a/test/dialect/postgresql/test_compiler.py b/test/dialect/postgresql/test_compiler.py
index 99706bad8..160641855 100644
--- a/test/dialect/postgresql/test_compiler.py
+++ b/test/dialect/postgresql/test_compiler.py
@@ -555,6 +555,30 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
                             'ALTER TABLE testtbl ADD EXCLUDE USING gist '
                             '(room WITH =)')
 
+    def test_exclude_constraint_copy_where_using(self):
+        m = MetaData()
+        tbl = Table('testtbl', m,
+                    Column('room', Integer, primary_key=True),
+                    )
+        cons = ExcludeConstraint(
+            (tbl.c.room, '='), where=tbl.c.room > 5, using='foobar')
+        tbl.append_constraint(cons)
+        self.assert_compile(
+            schema.AddConstraint(cons),
+            "ALTER TABLE testtbl ADD EXCLUDE USING foobar "
+            "(room WITH =) WHERE (testtbl.room > 5)"
+        )
+
+        m2 = MetaData()
+        tbl2 = tbl.tometadata(m2)
+        self.assert_compile(
+            schema.CreateTable(tbl2),
+            "CREATE TABLE testtbl (room SERIAL NOT NULL, "
+            "PRIMARY KEY (room), "
+            "EXCLUDE USING foobar "
+            "(room WITH =) WHERE (testtbl.room > 5))"
+        )
+
     def test_exclude_constraint_text(self):
         m = MetaData()
         cons = ExcludeConstraint((text('room::TEXT'), '='))