diff --git a/lcviz/helper.py b/lcviz/helper.py
index a0481494..2487dcec 100644
--- a/lcviz/helper.py
+++ b/lcviz/helper.py
@@ -31,7 +31,7 @@ def _get_range_subset_bounds(self, subset_state, *args, **kwargs):
         # TODO: use display units once implemented in Glue for ScatterViewer
         # units = u.Unit(viewer.state.x_display_unit)
         units = u.Unit(viewer.time_unit)
-    else:
+    else:  # pragma: no cover
         raise ValueError("Unable to find time axis units")
 
     region = reference_time + u.Quantity([subset_state.lo * units, subset_state.hi * units])
diff --git a/lcviz/plugins/ephemeris/ephemeris.py b/lcviz/plugins/ephemeris/ephemeris.py
index 4eb0a87e..38aecee0 100644
--- a/lcviz/plugins/ephemeris/ephemeris.py
+++ b/lcviz/plugins/ephemeris/ephemeris.py
@@ -280,7 +280,7 @@ def _on_component_remove(self, lbl):
         _ = self._ephemerides.pop(lbl, {})
         # remove the corresponding viewer, if it exists
         viewer_item = self.app._viewer_item_by_id(self._phase_viewer_id(lbl))
-        if viewer_item is None:
+        if viewer_item is None:  # pragma: no cover
             return
         cid = viewer_item.get('id', None)
         if cid is not None:
@@ -346,7 +346,7 @@ def update_ephemeris(self, component=None, t0=None, period=None, dpdt=None):
         if component is None:
             component = self.component_selected
 
-        if component not in self.component.choices:
+        if component not in self.component.choices:  # pragma: no cover
             raise ValueError(f"component must be one of {self.component.choices}")
 
         existing_ephem = self._ephemerides.get(component, {})
@@ -411,7 +411,7 @@ def _update_periodogram(self, *args):
                 self.method_spinner = False
                 self.method_err = str(err)
                 return
-        else:
+        else:  # pragma: no cover
             self.method_spinner = False
             raise NotImplementedError(f"periodogram not implemented for {self.method}")
 
diff --git a/lcviz/tests/test_plugin_ephemeris.py b/lcviz/tests/test_plugin_ephemeris.py
index 587e170e..a837b6d3 100644
--- a/lcviz/tests/test_plugin_ephemeris.py
+++ b/lcviz/tests/test_plugin_ephemeris.py
@@ -31,6 +31,22 @@ def test_plugin_ephemeris(helper, light_curve_like_kepler_quarter):
     assert 'renamed custom component' in ephem.ephemerides
     assert len(helper.app.get_viewer_ids()) == 3
 
+    assert ephem.component == 'renamed custom component'
+    assert ephem.period == 3.14
+    assert ephem.ephemeris['period'] == 3.14
+    # modify the ephemeris of the NON-selected ephemeris component
+    ephem.update_ephemeris(component='default', period=2)
+    assert ephem.period == 3.14
+    assert ephem.ephemerides['default']['period'] == 2
+
     ephem.remove_component('renamed custom component')
     assert len(ephem.ephemerides) == 1
     assert len(helper.app.get_viewer_ids()) == 2
+    assert ephem.component == 'default'
+    assert ephem.period == 2
+
+    assert ephem.method.selected == 'Lomb-Scargle'
+    ephem.method = 'Box Least Squares'
+    assert ephem._obj.method_err == ''
+    ephem._obj.vue_adopt_period_at_max_power()
+    assert ephem.period != 2
diff --git a/lcviz/utils.py b/lcviz/utils.py
index 1bb0e28e..3dbff498 100644
--- a/lcviz/utils.py
+++ b/lcviz/utils.py
@@ -25,7 +25,7 @@ class TimeCoordinates(Coordinates):
     """
 
     def __init__(self, times, reference_time=None, unit=u.d):
-        if not isinstance(times, Time):
+        if not isinstance(times, Time):  # pragma: no cover
             raise TypeError('values should be a Time instance')
         self._index = np.arange(len(times))
         self._times = times
@@ -44,7 +44,7 @@ def time_axis(self):
         return self._times
 
     def world_to_pixel_values(self, *world):
-        if len(world) > 1:
+        if len(world) > 1:  # pragma: no cover
             raise ValueError('TimeCoordinates is a 1-d coordinate class '
                              'and only accepts a single scalar or array to convert')
         return interp1d(
@@ -52,7 +52,7 @@ def world_to_pixel_values(self, *world):
         )(world[0])
 
     def pixel_to_world_values(self, *pixel):
-        if len(pixel) > 1:
+        if len(pixel) > 1:  # pragma: no cover
             raise ValueError('SpectralCoordinates is a 1-d coordinate class '
                              'and only accepts a single scalar or array to convert')
         return interp1d(