Allow workflow argument to be a dict (#245)

* Allow for workflow arg as a dict and typecheck it

src/fmu/dataio/_fmu_provider.py

@@ -211,7 +211,24 @@ def generate_ert2_metadata(self):
         meta["context"] = {"stage": self.dataio._usecontext}
 
         if self.dataio.workflow:
-            meta["workflow"] = {"reference": self.dataio.workflow}
+            if isinstance(self.dataio.workflow, str):
+                meta["workflow"] = {"reference": self.dataio.workflow}
+            elif isinstance(self.dataio.workflow, dict):
+                if "reference" not in self.dataio.workflow:
+                    raise ValueError(
+                        "When workflow is given as a dict, the 'reference' "
+                        "key must be included and be a string"
+                    )
+                warn(
+                    "The 'workflow' argument should be given as a string. "
+                    "Support for dictionary input is scheduled for deprecation.",
+                    PendingDeprecationWarning,
+                )
+
+                meta["workflow"] = {"reference": self.dataio.workflow["reference"]}
+
+            else:
+                raise TypeError("'workflow' should be string.")
 
         case_uuid = "not_present"  # TODO! not allow missing case metadata?
         if self.case_metadata and "fmu" in self.case_metadata:

src/fmu/dataio/dataio.py

@@ -309,8 +309,6 @@ class ExportData:
 
         grid_model: Currently allowed but planned for deprecation
 
-        grid_model: Currently allowed but planned for deprecation
-
         include_index: This applies to Pandas (table) data only, and if True then the
             index column will be exported. Deprecated, use class variable
             ``table_include_index`` instead

tests/test_units/test_fmuprovider_class.py

@@ -1,6 +1,8 @@
 """Test the _MetaData class from the _metadata.py module"""
 import os
 
+import pytest
+
 import fmu.dataio as dio
 from fmu.dataio._fmu_provider import _FmuProvider, _get_folderlist
 
@@ -73,3 +75,48 @@ def test_fmuprovider_detect_case_has_metadata(fmurun_w_casemetadata, edataobj1):
         myfmu.case_metadata["fmu"]["case"]["uuid"]
         == "a40b05e8-e47f-47b1-8fee-f52a5116bd37"
     )
+
+
+def test_fmuprovider_workflow_reference(fmurun_w_casemetadata, edataobj1):
+    """Testing the handling of workflow reference input.
+
+    Metadata definitions of fmu.workflow is that it is a dictionary with 'reference'
+    as a mandatory key. In early versions, the 'workflow' argument was to be given as
+    a dictionary and directly inserted. However, during development, this has changed
+    to a string which is inserted into the 'workflow' element in the outgoing metadata.
+    Some users still have legacy workflows that give this as a dictionary, so we will
+    continue to allow it, but with a warning.
+
+    This test is asserting that when 'workflow' is given in various shapes and forms,
+    it shall always produce valid metadata.
+
+    """
+    edataobj1._rootpath = fmurun_w_casemetadata
+    os.chdir(fmurun_w_casemetadata)
+
+    # workflow input is a string
+    edataobj1.workflow = "my workflow"
+    myfmu = _FmuProvider(edataobj1)
+    myfmu.detect_provider()
+    assert "workflow" in myfmu.metadata
+    assert myfmu.metadata["workflow"] == {"reference": "my workflow"}
+
+    # workflow input is a correct dict
+    edataobj1.workflow = {"reference": "my workflow"}
+    myfmu = _FmuProvider(edataobj1)
+    with pytest.warns(PendingDeprecationWarning, match="The 'workflow' argument"):
+        myfmu.detect_provider()
+    assert "workflow" in myfmu.metadata
+    assert myfmu.metadata["workflow"] == {"reference": "my workflow"}
+
+    # workflow input is non-correct dict
+    edataobj1.workflow = {"something": "something"}
+    myfmu = _FmuProvider(edataobj1)
+    with pytest.raises(ValueError):
+        myfmu.detect_provider()
+
+    # workflow input is other types - shall fail
+    edataobj1.workflow = 123.4
+    myfmu = _FmuProvider(edataobj1)
+    with pytest.raises(TypeError):
+        myfmu.detect_provider()