String compiler can now literal compile datetime objects

Add ability to literal compile a :class:`DateTime`, :class:`Date`
or :class:"Time" when using the string dialect for debugging purposes.
This change does not impact real dialect implementation that retain
their current behavior.

Fixes: #5052
Change-Id: Ia3fad2be905c6d35b0106b9a2388c7508f067e90

2 files changed, 39 insertions, 0 deletions

diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py
index ef3e5d26e..151ecb1d2 100644
--- a/test/sql/test_compiler.py
+++ b/test/sql/test_compiler.py
@@ -10,6 +10,7 @@ styling and coherent test organization.
 
 """
 
+import datetime
 import decimal
 
 from sqlalchemy import alias
@@ -3745,6 +3746,21 @@ class StringifySpecialTest(fixtures.TestBase):
             "WITHIN GROUP (ORDER BY mytable.name DESC) AS anon_1 FROM mytable",
         )
 
+    @testing.combinations(
+        ("datetime", datetime.datetime.now()),
+        ("date", datetime.date.today()),
+        ("time", datetime.time()),
+        argnames="value",
+        id_="ia",
+    )
+    def test_render_datetime(self, value):
+        lit = literal(value)
+
+        eq_ignore_whitespace(
+            str(lit.compile(compile_kwargs={"literal_binds": True})),
+            "'%s'" % value,
+        )
+
 
 class KwargPropagationTest(fixtures.TestBase):
     @classmethod
diff --git a/test/sql/test_types.py b/test/sql/test_types.py
index 9fb79958d..2af8cb325 100644
--- a/test/sql/test_types.py
+++ b/test/sql/test_types.py
@@ -3237,3 +3237,26 @@ class CallableTest(fixtures.TestBase):
         )
         assert isinstance(thang_table.c.name.type, Unicode)
         thang_table.create()
+
+
+class LiteralTest(fixtures.TestBase):
+    __backend__ = True
+
+    @testing.combinations(
+        ("datetime", datetime.datetime.now()),
+        ("date", datetime.date.today()),
+        ("time", datetime.time()),
+        argnames="value",
+        id_="ia",
+    )
+    @testing.skip_if(lambda: testing.requires.datetime_literals)
+    def test_render_datetime(self, value):
+        lit = literal(value)
+
+        assert_raises_message(
+            NotImplementedError,
+            "Don't know how to literal-quote value.*",
+            lit.compile,
+            dialect=testing.db.dialect,
+            compile_kwargs={"literal_binds": True},
+        )