diff --git a/src/yt_napari/_tests/test_widget_reader.py b/src/yt_napari/_tests/test_widget_reader.py
index 8b51597..2f2c6a8 100644
--- a/src/yt_napari/_tests/test_widget_reader.py
+++ b/src/yt_napari/_tests/test_widget_reader.py
@@ -10,6 +10,7 @@
 import numpy as np
 
 from yt_napari import _widget_reader as _wr
+from yt_napari._data_model import InputModel
 from yt_napari._ds_cache import dataset_cache
 
 # import ReaderWidget, SelectionEntry, TimeSeriesReader
@@ -48,7 +49,7 @@ def _rebuild_data(final_shape, data):
     return np.random.random(final_shape) * data.mean()
 
 
-def test_save_widget_reader(make_napari_viewer, yt_ugrid_ds_fn):
+def test_save_widget_reader(make_napari_viewer, yt_ugrid_ds_fn, tmp_path):
     viewer = make_napari_viewer()
     r = _wr.ReaderWidget(napari_viewer=viewer)
     r.ds_container.filename.value = yt_ugrid_ds_fn
@@ -65,7 +66,7 @@ def test_save_widget_reader(make_napari_viewer, yt_ugrid_ds_fn):
     rebuild = partial(_rebuild_data, mgui_region.resolution.value)
     r._post_load_function = rebuild
 
-    temp_file = "test.json"
+    temp_file = tmp_path / "test.json"
 
     with patch("PyQt5.QtWidgets.QFileDialog.exec_") as mock_exec, patch(
         "PyQt5.QtWidgets.QFileDialog.selectedFiles"
@@ -94,15 +95,11 @@ def test_save_widget_reader(make_napari_viewer, yt_ugrid_ds_fn):
         400,
     ]
 
-    os.remove(temp_file)
+    # ensure that the saved json is a valid model
+    _ = InputModel.parse_obj(saved_data)
     r.deleteLater()
 
 
-def simulate_file_selection(args, **kwargs):
-    # Simulate filling in a file name, selecting a file type, and closing the dialog
-    return ("selected_file.json", "JSON Files (.json)")
-
-
 def test_widget_reader(make_napari_viewer, yt_ugrid_ds_fn):
     viewer = make_napari_viewer()
     r = _wr.ReaderWidget(napari_viewer=viewer)
@@ -196,7 +193,7 @@ def test_timeseries_widget_reader(make_napari_viewer, tmp_path):
     tsr.load_data()
     assert len(viewer.layers) == 2
 
-    temp_file = "test.json"
+    temp_file = tmp_path / "test.json"
 
     # Use patch to replace the actual QFileDialog functions with mock functions
     with patch("PyQt5.QtWidgets.QFileDialog.exec_") as mock_exec, patch(
@@ -231,6 +228,7 @@ def test_timeseries_widget_reader(make_napari_viewer, tmp_path):
         10,
     ]
 
-    os.remove(temp_file)
+    # ensure that the saved json is a valid model
+    _ = InputModel.parse_obj(saved_data)
 
     tsr.deleteLater()
diff --git a/src/yt_napari/_widget_reader.py b/src/yt_napari/_widget_reader.py
index 2f62d90..d675b21 100644
--- a/src/yt_napari/_widget_reader.py
+++ b/src/yt_napari/_widget_reader.py
@@ -77,7 +77,9 @@ def add_spatial_selection_widgets(self):
         self.layout().addLayout(removal_group_layout)
 
     def add_load_group_widgets(self):
-        pass
+        """
+        add the widgets related to the Load button
+        """
 
     def add_a_selection(self):
         selection_type = self.new_selection_type.currentText()