Added default value loop test

Author: GlassOfWhiskey

tests/loop/default-value-loop.cwl

@@ -0,0 +1,51 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: v1.2
+class: Workflow
+$namespaces:
+  cwltool: "http://commonwl.org/cwltool#"
+requirements:
+  InlineJavascriptRequirement: {}
+  ScatterFeatureRequirement: {}
+  SubworkflowFeatureRequirement: {}
+inputs:
+  i1: int
+outputs:
+  o1:
+    type: int[]
+    outputSource: loop/o1
+    pickValue: all_non_null
+steps:
+  loop:
+    run:
+      class: Workflow
+      inputs:
+        i1: int
+      outputs:
+        o1:
+          type: int?
+          outputSource: big_values/o1
+      steps:
+        big_values:
+          when: $(inputs.i1 >= 5)
+          run:
+            class: ExpressionTool
+            inputs:
+              i1: int
+            outputs:
+              o1: int
+            expression: >
+              ${return {'o1': inputs.i1 + 3};}
+          in:
+            i1: i1
+          out: [ o1 ]
+    in:
+      i1: i1
+    out: [ o1 ]
+    requirements:
+      cwltool:Loop:
+        loop_when: $(inputs.i1 < 20)
+        loop:
+          i1:
+            loop_source: o1
+            default: 5
+        outputMethod: all

tests/test_loop.py

@@ -169,3 +169,17 @@ def test_multi_source_loop_input() -> None:
     main(params, stdout=stream)
     expected = {'o1': [2, 3, 4, 5, 8, 11, 14, 17, 20]}
     assert json.loads(stream.getvalue()) == expected
+
+
+def test_default_value_loop() -> None:
+    """Test a loop whose source has a defautl value."""
+    stream = StringIO()
+    params = [
+        "--enable-ext",
+        "--validate",
+        get_data("tests/loop/default-value-loop.cwl"),
+        get_data("tests/loop/single-var-loop-job.yml")
+    ]
+    main(params, stdout=stream)
+    expected = {'o1': [8, 11, 14, 17, 20]}
+    assert json.loads(stream.getvalue()) == expected