diff --git a/specreduce/tests/test_tracing.py b/specreduce/tests/test_tracing.py
index 3421d00..b8040ed 100644
--- a/specreduce/tests/test_tracing.py
+++ b/specreduce/tests/test_tracing.py
@@ -156,8 +156,6 @@ def test_fit_trace():
     nddat = NDData(data=img, mask=mask, unit=u.DN)
     warn_bins = np.arange(20)
     warn_bins = ', '.join([str(x) for x in warn_bins])
-    msg = f"All pixels in bin 75 are masked. Falling to trace value from all-bin fit."
+    msg = f"All pixels in bin {warn_bins} are masked. Falling to trace value from all-bin fit."
     with pytest.warns(UserWarning, match=msg):
         FitTrace(nddat)
-
-    # could try to catch warning thrown for all-nan bins
\ No newline at end of file
diff --git a/specreduce/tracing.py b/specreduce/tracing.py
index f7838f3..ba06c9b 100644
--- a/specreduce/tracing.py
+++ b/specreduce/tracing.py
@@ -310,7 +310,6 @@ def __post_init__(self):
                 warn_bins.append(i)
                 peak_y_i = peak_y
 
-
             if self.peak_method == 'gaussian':
                 yy_i_above_half_max = np.sum(z_i > (z_i.max() / 2))
                 width_guess_i = yy_i_above_half_max / gaussian_sigma_to_fwhm
@@ -355,7 +354,7 @@ def __post_init__(self):
             if len(warn_bins) > 20:
                 warn_bins = warn_bins[0: 10] + ['...'] + warn_bins[10: 19]
             warnings.warn(f"All pixels in bin{plural} {', '.join([str(x) for x in warn_bins])}"
-                            " are masked. Falling to trace value from all-bin fit.")
+                           " are masked. Falling to trace value from all-bin fit.")
 
         # recenter bin positions
         x_bins = (x_bins[:-1] + x_bins[1:]) / 2