Fix: Make sure default image can be found (#698)

Signed-off-by: Tim Bauer <[email protected]>

flytekit/core/context_manager.py

@@ -92,7 +92,8 @@ def find_image(self, name) -> Optional[Image]:
         """
         Return an image, by name, if it exists.
         """
-        for i in self.images:
+        lookup_images = self.images + [self.default_image] if self.images else [self.default_image]
+        for i in lookup_images:
             if i.name == name:
                 return i
         return None

tests/flytekit/unit/core/test_python_auto_container.py

@@ -0,0 +1,16 @@
+import pytest
+
+from flytekit.core.context_manager import Image, ImageConfig
+from flytekit.core.python_auto_container import get_registerable_container_image
+
+
+@pytest.fixture
+def default_image_config():
+    default_image = Image(name="default", fqn="docker.io/xyz", tag="some-git-hash")
+    return ImageConfig(default_image=default_image)
+
+
+def test_image_name_interpolation(default_image_config):
+    img_to_interpolate = "{{.image.default.fqn}}:{{.image.default.version}}-special"
+    img = get_registerable_container_image(img=img_to_interpolate, cfg=default_image_config)
+    assert img == "docker.io/xyz:some-git-hash-special"