Merge pull request #255 from djarecka/fix/numpy_wfoutput

fixing is_existing_file, so doesn't have problem with arrays (closes #251)

Author: nicolocin

pydra/engine/helpers_file.py

@@ -535,11 +535,11 @@ def is_local_file(f):
     return f.type is File and "container_path" not in f.metadata
 
 
-def is_existing_file(f):
+def is_existing_file(value):
     """ checking if an object is an existing file"""
-    if not f:
+    if value == "":
         return False
     try:
-        return Path(f).exists()
+        return Path(value).exists()
     except TypeError:
         return False

pydra/engine/tests/test_numpy_examples.py

@@ -0,0 +1,35 @@
+import numpy as np
+import typing as ty
+import importlib
+import pytest
+
+from ..submitter import Submitter
+from ..core import Workflow
+from ...mark import task, annotate
+
+if importlib.util.find_spec("numpy") is None:
+    pytest.skip("can't find numpy library", allow_module_level=True)
+
+
+@task
+@annotate({"return": {"b": ty.Any}})
+def arrayout(val):
+    return np.array([val, val])
+
+
+def test_multiout(plugin):
+    """ testing a simple function that returns a numpy array"""
+    wf = Workflow("wf", input_spec=["val"], val=[0, 1, 2])
+    wf.add(arrayout(name="mo", val=wf.lzin.val))
+    wf.mo.split("val").combine("val")
+
+    wf.set_output([("array", wf.mo.lzout.b)])
+
+    with Submitter(plugin=plugin, n_procs=2) as sub:
+        sub(runnable=wf)
+
+    results = wf.result(return_inputs=True)
+
+    assert results[0] == {"wf.val": [0, 1, 2]}
+    for el in range(3):
+        assert np.array_equal(results[1].output.array[el], np.array([el, el]))