Test that measured data work with failed reals

This caused the misfit preprocessor to fail when run
on cases that have failed realizations.

src/ert/data/_measured_data.py

@@ -107,10 +107,11 @@ def _get_data(
                 response = ensemble.load_response(
                     group, tuple(ensemble.realization_list(RealizationState.HAS_DATA))
                 )
+                _msg = f"No response loaded for observation key: {key}"
+                if not response:
+                    raise ResponseError(_msg)
             except KeyError as e:
-                raise ResponseError(
-                    f"No response loaded for observation key: {key}"
-                ) from e
+                raise ResponseError(_msg) from e
             ds = obs.merge(
                 response,
                 join="left",

tests/unit_tests/gui/test_full_manual_update_workflow.py

@@ -4,6 +4,7 @@
 from qtpy.QtCore import Qt, QTimer
 from qtpy.QtWidgets import QApplication, QComboBox, QMessageBox, QPushButton, QWidget
 
+from ert.data import MeasuredData
 from ert.gui.ertwidgets.caselist import CaseList
 from ert.gui.simulation.ensemble_experiment_panel import EnsembleExperimentPanel
 from ert.gui.simulation.run_dialog import RunDialog
@@ -127,6 +128,9 @@ def handle_dialog():
     df_prior = facade.load_all_gen_kw_data(storage.get_ensemble_by_name("iter-0"))
     df_posterior = facade.load_all_gen_kw_data(storage.get_ensemble_by_name("iter-1"))
 
+    # Making sure measured data works with failed realizations
+    MeasuredData(facade, storage.get_ensemble_by_name("iter-0"), ["POLY_OBS"])
+
     # We expect that ERT's update step lowers the
     # generalized variance for the parameters.
     assert (