Fixes SerialWorker Implementation

pydra/engine/specs.py

@@ -567,7 +567,7 @@ def _field_metadata(
                     if "mandatory" in fld.metadata:
                         if fld.metadata["mandatory"]:
                             raise Exception(
-                                f"mandatory output for variable {fld.name} does not exit"
+                                f"mandatory output for variable {fld.name} does not exist"
                             )
                     return attr.NOTHING
                 return val

pydra/engine/tests/test_shelltask.py

@@ -4453,7 +4453,7 @@ def test_shell_cmd_non_existing_outputs_4(tmpdir):
     # An exception should be raised because the second mandatory output does not exist
     with pytest.raises(Exception) as excinfo:
         shelly()
-    assert "mandatory output for variable out_2 does not exit" == str(excinfo.value)
+    assert "mandatory output for variable out_2 does not exist" == str(excinfo.value)
     # checking if the first output was created
     assert (Path(shelly.output_dir) / Path("test_1.nii")).exists()
 

pydra/engine/tests/test_submitter.py

@@ -175,6 +175,13 @@ def test_wf_with_state(plugin_dask_opt, tmpdir):
     assert res[2].output.out == 5
 
 
+def test_serial_wf():
+    # Use serial plugin to execute workflow instead of CF
+    wf = gen_basic_wf()
+    res = wf(plugin="serial")
+    assert res.output.out == 9
+
+
 @pytest.mark.skipif(not slurm_available, reason="slurm not installed")
 def test_slurm_wf(tmpdir):
     wf = gen_basic_wf()

pydra/engine/workers.py

@@ -116,38 +116,30 @@ async def fetch_finished(self, futures):
         return pending.union(unqueued)
 
 
-class SerialPool:
-    """A simple class to imitate a pool executor of concurrent futures."""
-
-    def submit(self, interface, **kwargs):
-        """Send new task."""
-        self.res = interface(**kwargs)
-
-    def result(self):
-        """Get the result of a task."""
-        return self.res
-
-    def done(self):
-        """Return whether the task is finished."""
-        return True
-
-
 class SerialWorker(Worker):
     """A worker to execute linearly."""
 
     def __init__(self):
         """Initialize worker."""
         logger.debug("Initialize SerialWorker")
-        self.pool = SerialPool()
 
     def run_el(self, interface, rerun=False, **kwargs):
         """Run a task."""
-        self.pool.submit(interface=interface, rerun=rerun, **kwargs)
-        return self.pool
+        return self.exec_serial(interface, rerun=rerun)
 
     def close(self):
         """Return whether the task is finished."""
 
+    async def exec_serial(self, runnable, rerun=False):
+        return runnable()
+
+    async def fetch_finished(self, futures):
+        await asyncio.gather(*futures)
+        return set([])
+
+    # async def fetch_finished(self, futures):
+    #     return await asyncio.wait(futures)
+
 
 class ConcurrentFuturesWorker(Worker):
     """A worker to execute in parallel using Python's concurrent futures."""