PwBaseWorkChain: do no assume output_band exists in band sanity c…

…heck (#544)

The `output_band` output of the `PwCalculation` is optional and, for
example, when the setting `no_bands=True`, the band files will not be
retrieved and consequentially not parsed. The process handler checking
the bands `sanity_check_insufficient_bands`, however, assumed the output
node is always there. This is changed to simply skip the check if the
node is not there.

Note that we do not check in the workchain whether the output should
have been there, because the sanity check is only triggered for
successful calculations, and if the output should have been there, the
calculation should have been failed. If this is not the case, that is a
bug in the parser and should be addressed there.

aiida_quantumespresso/workflows/pw/base.py

@@ -255,7 +255,7 @@ def run_init(self):
         inputs = prepare_process_inputs(PwCalculation, inputs)
         running = self.submit(PwCalculation, **inputs)
 
-        self.report('launching initialization {}<{}>'.format(running.pk, self._process_class.__name__))
+        self.report('launching initialization {}<{}>'.format(running.pk, self.ctx.process_name))
 
         return ToContext(calculation_init=running)
 
@@ -336,9 +336,15 @@ def sanity_check_insufficient_bands(self, calculation):
 
         try:
             bands = calculation.outputs.output_band
+        except AttributeError:
+            args = [self.ctx.process_name, calculation.pk]
+            self.report('{}<{}> does not have `output_band` output, skipping sanity check.'.format(*args))
+            return
+
+        try:
             get_highest_occupied_band(bands)
         except ValueError as exception:
-            args = [self._process_class.__name__, calculation.pk]
+            args = [self.ctx.process_name, calculation.pk]
             self.report('{}<{}> run with smearing and highest band is occupied'.format(*args))
             self.report('BandsData<{}> has invalid occupations: {}'.format(bands.pk, exception))
             self.report('{}<{}> had insufficient bands'.format(calculation.process_label, calculation.pk))

tests/workflows/pw/test_base.py

@@ -6,7 +6,8 @@
 from plumpy import ProcessState
 
 from aiida.common import AttributeDict
-from aiida.engine import ProcessHandlerReport
+from aiida.engine import ExitCode, ProcessHandlerReport
+from aiida.orm import Dict
 
 from aiida_quantumespresso.calculations.pw import PwCalculation
 from aiida_quantumespresso.workflows.pw.base import PwBaseWorkChain
@@ -23,7 +24,7 @@ def _generate_workchain_pw(exit_code=None):
         process = generate_workchain(entry_point, {'pw': inputs, 'kpoints': kpoints})
 
         if exit_code is not None:
-            node = generate_calc_job_node()
+            node = generate_calc_job_node(inputs={'parameters': Dict()})
             node.set_process_state(ProcessState.FINISHED)
             node.set_exit_status(exit_code.status)
 
@@ -133,3 +134,12 @@ def test_handle_relax_recoverable_ionic_convergence_error(
 
     result = process.inspect_process()
     assert result.status == 0
+
+
+def test_sanity_check_no_bands(aiida_profile, generate_workchain_pw):
+    """Test that `sanity_check_insufficient_bands` does not except if there is no `output_band`, which is optional."""
+    process = generate_workchain_pw(exit_code=ExitCode(0))
+    process.setup()
+
+    calculation = process.ctx.children[-1]
+    assert process.sanity_check_insufficient_bands(calculation) is None