Add unit test for a workflow using an expression for the resources

tests/test_reqs_hints.py

@@ -0,0 +1,56 @@
+"""Test for Requirements and Hints in cwltool."""
+import json
+from io import StringIO
+
+from cwltool.main import main
+from .util import get_data
+
+
+def test_workflow_reqs_are_evaluated_eagerly_default_args() -> None:
+    """Test that a Workflow process will evaluate the requirements eagerly.
+    Uses the default input values.
+
+    This means that workflow steps, such as Expression and Command Line Tools
+    can both use resources without re-evaluating expressions. This is useful
+    when you have an expression that, for instance, dynamically decides
+    how many threads/cpus to use.
+
+    Issue: https://github.com/common-workflow-language/cwltool/issues/1330
+    """
+    stream = StringIO()
+
+    assert (
+            main(
+                [get_data("tests/wf/1330.cwl")],
+                stdout=stream,
+            )
+            == 0
+    )
+
+    out = json.loads(stream.getvalue())
+    assert out["out"] == "4\n"
+
+
+def test_workflow_reqs_are_evaluated_eagerly_provided_inputs() -> None:
+    """Test that a Workflow process will evaluate the requirements eagerly.
+    Passes inputs via a job file.
+
+    This means that workflow steps, such as Expression and Command Line Tools
+    can both use resources without re-evaluating expressions. This is useful
+    when you have an expression that, for instance, dynamically decides
+    how many threads/cpus to use.
+
+    Issue: https://github.com/common-workflow-language/cwltool/issues/1330
+    """
+    stream = StringIO()
+
+    assert (
+            main(
+                [get_data("tests/wf/1330.cwl"), get_data("tests/wf/1330.json")],
+                stdout=stream,
+            )
+            == 0
+    )
+
+    out = json.loads(stream.getvalue())
+    assert out["out"] == "3\n"

tests/wf/1330.cwl

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+# Original file: tests/eager-eval-reqs-hints/wf-reqs.cwl
+# From: https://github.com/common-workflow-language/cwl-v1.2/pull/195
+cwlVersion: v1.2
+class: Workflow
+
+requirements:
+  ResourceRequirement:
+    coresMax: $(inputs.threads_max)
+
+inputs:
+  threads_max:
+    type: int
+    default: 4
+
+steps:
+  one:
+    in: []
+    run:
+      class: CommandLineTool
+      inputs:
+        other_input:
+          type: int
+          default: 8
+      baseCommand: echo
+      arguments: [ $(runtime.cores) ]
+      stdout: out.txt
+      outputs:
+        out:
+          type: string
+          outputBinding:
+            glob: out.txt
+            loadContents: true
+            outputEval: $(self[0].contents)
+    out: [out]
+
+outputs:
+  out:
+    type: string
+    outputSource: one/out

tests/wf/1330.json

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+{
+  "threads_max": 3
+}