fix tests and add traverse workflow for singularity pull

Author: khillion

tests/test_docker_extract.py

@@ -2,7 +2,8 @@
 from pathlib import Path
 from os import environ
 from tempfile import TemporaryDirectory
-from cwl_utils.docker_extract import traverse, get_image_name, save_docker_image, load_docker_image
+from cwl_utils.docker_extract import traverse
+from cwl_utils.image_puller import DockerImagePuller, SingularityImagePuller
 import cwl_utils.parser_v1_0 as parser
 
 HERE = Path(__file__).resolve().parent
@@ -17,6 +18,15 @@ def test_traverse_workflow(self):
 
         with TemporaryDirectory() as tmpdir:
             for req in set(traverse(loaded)):
-                image_name = get_image_name(req)
-                save_docker_image(req, image_name, tmpdir)
-                _ = load_docker_image(image_name)
+                image_puller = DockerImagePuller(req, tmpdir)
+                image_puller.save_docker_image()
+                _ = image_puller.generate_udocker_loading_command()
+
+    @skipIf(TRAVIS, reason="travis doesn't running docker in singularity")
+    def test_traverse_workflow_singularity(self):
+        loaded = parser.load_document(str(TEST_CWL.resolve()))
+
+        with TemporaryDirectory() as tmpdir:
+            for req in set(traverse(loaded)):
+                image_puller = SingularityImagePuller(req, tmpdir)
+                image_puller.save_docker_image()