Default to the "original" SVG rendition if none of the passed filters…

… SVG-safe

grapple/types/images.py

@@ -146,6 +146,9 @@ def resolve_rendition(
         if instance.is_svg() and preserve_svg:
             # when dealing with SVGs, we want to limit the filter specs to those that are safe
             filter_specs = to_svg_safe_spec(filter_specs)
+            if not filter_specs:
+                # if there are no valid filters, fall back to the original
+                filter_specs = "original"
 
             if not filter_specs:
                 raise TypeError(

tests/test_image_types.py

@@ -302,7 +302,9 @@ def test_svg_rendition_with_raster_format_with_preserve_svg(self):
             query, variables={"id": self.example_svg_image.id}
         )
         self.assertTrue(
-            results["data"]["image"]["rendition"]["url"].endswith("test.width-150.svg")
+            results["data"]["image"]["rendition"]["url"].endswith(
+                "grapple-test.width-150.svg"
+            )
         )
 
     def test_svg_src_set_with_raster_format_with_preserve_svg(self):
@@ -318,7 +320,9 @@ def test_svg_src_set_with_raster_format_with_preserve_svg(self):
             query, variables={"id": self.example_svg_image.id}
         )
         self.assertTrue(
-            results["data"]["image"]["srcSet"].split()[0].endswith("test.width-100.svg")
+            results["data"]["image"]["srcSet"]
+            .split()[0]
+            .endswith("grapple-test.width-100.svg")
         )
 
     def test_svg_rendition_with_raster_format_without_preserve_svg(self):
@@ -372,8 +376,8 @@ def test_svg_rendition_with_filters_passed_through_to_svg_safe_spec(self):
         results = self.client.execute(
             query, variables={"id": self.example_svg_image.id}
         )
-        self.assertIsNone(results["data"]["image"]["rendition"])
-        self.assertEqual(
-            results["errors"][0]["message"],
-            "No valid filter specs for SVG. See https://docs.wagtail.org/en/stable/topics/images.html#svg-images for details.",
+        self.assertTrue(
+            results["data"]["image"]["rendition"]["url"].endswith(
+                "grapple-test.original.svg"
+            )
         )