- Added new checks for the common error case of passing mapped classes

or mapped instances into contexts where they are interpreted as
SQL bound parameters; a new exception is raised for this.
fixes #3321

1 files changed, 23 insertions, 2 deletions

diff --git a/test/sql/test_types.py b/test/sql/test_types.py
index 0ab8ef451..90fac97c2 100644
--- a/test/sql/test_types.py
+++ b/test/sql/test_types.py
@@ -1,5 +1,6 @@
 # coding: utf-8
-from sqlalchemy.testing import eq_, assert_raises, assert_raises_message, expect_warnings
+from sqlalchemy.testing import eq_, is_, assert_raises, \
+    assert_raises_message, expect_warnings
 import decimal
 import datetime
 import os
@@ -11,7 +12,7 @@ from sqlalchemy import (
     BLOB, NCHAR, NVARCHAR, CLOB, TIME, DATE, DATETIME, TIMESTAMP, SMALLINT,
     INTEGER, DECIMAL, NUMERIC, FLOAT, REAL)
 from sqlalchemy.sql import ddl
-
+from sqlalchemy import inspection
 from sqlalchemy import exc, types, util, dialects
 for name in dialects.__all__:
     __import__("sqlalchemy.dialects.%s" % name)
@@ -1647,6 +1648,26 @@ class ExpressionTest(
         assert distinct(test_table.c.data).type == test_table.c.data.type
         assert test_table.c.data.distinct().type == test_table.c.data.type
 
+    def test_detect_coercion_of_builtins(self):
+        @inspection._self_inspects
+        class SomeSQLAThing(object):
+            def __repr__(self):
+                return "some_sqla_thing()"
+
+        class SomeOtherThing(object):
+            pass
+
+        assert_raises_message(
+            exc.ArgumentError,
+            r"Object some_sqla_thing\(\) is not legal as a SQL literal value",
+            lambda: column('a', String) == SomeSQLAThing()
+        )
+
+        is_(
+            bindparam('x', SomeOtherThing()).type,
+            types.NULLTYPE
+        )
+
 
 class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
     __dialect__ = 'default'