Add failing test for issue #3868 (#4378)

tests/test_bound_fields.py

@@ -55,6 +55,30 @@ class TestSimpleBoundField:
         assert serializer['bool_field'].as_form_field().value == ''
         assert serializer['null_field'].as_form_field().value == ''
 
+    def test_rendering_boolean_field(self):
+        from rest_framework.renderers import HTMLFormRenderer
+
+        class ExampleSerializer(serializers.Serializer):
+            bool_field = serializers.BooleanField(
+                style={'base_template': 'checkbox.html', 'template_pack': 'rest_framework/vertical'})
+
+        serializer = ExampleSerializer(data={'bool_field': True})
+        assert serializer.is_valid()
+        renderer = HTMLFormRenderer()
+        rendered = renderer.render_field(serializer['bool_field'], {})
+        expected_packed = (
+            '<divclass="form-group">'
+            '<divclass="checkbox">'
+            '<label>'
+            '<inputtype="checkbox"name="bool_field"value="true"checked>'
+            'Boolfield'
+            '</label>'
+            '</div>'
+            '</div>'
+        )
+        rendered_packed = ''.join(rendered.split())
+        assert rendered_packed == expected_packed
+
 
 class TestNestedBoundField:
     def test_nested_empty_bound_field(self):