Create an all-inclusive example unit test for ground-based data. (#796)

* Create an all-inclusive example unit test for ground-based data.

This work aims to solve two problems:

- Lack of an example unit test for ground telescope data which
  can be used as a starting point (by removing various things)
  for future unit tests.

- Inconsistent techniques for "scanning from a map" across many
  unit tests.  Basically I have removed ad-hoc code for generating
  fake sky signal and scanning into timestreams and centralized
  that in several unit test helper functions.

* Fix modified unit tests.

* Fix monopole subtraction when plotting wcs maps

* Remove stale, commented code

src/toast/templates/offset/offset.py

@@ -1156,7 +1156,10 @@ def plot(amp_file, compare=dict(), out=None):
             fig = plt.figure(dpi=fig_dpi, figsize=(fig_width, fig_height))
             ax = fig.add_subplot(1, 1, 1)
             if det in compare:
-                ax.plot(x_samples, compare[det], color="black", label=f"{det} Data")
+                dc = np.mean(compare[det])
+                ax.plot(
+                    x_samples, compare[det] - dc, color="black", label=f"{det} Data"
+                )
             ax.step(
                 amp_first[:],
                 hamps[idet],

src/toast/templates/periodic.py

@@ -552,10 +552,12 @@ def plot(amp_file, out_root=None):
             amp_max = list(ast.literal_eval(obgrp.attrs["max"]))
             amp_incr = list(ast.literal_eval(obgrp.attrs["incr"]))
 
-            hamps = obgrp["amplitudes"]
-            hhits = obgrp["hits"]
-            hflags = obgrp["flags"]
+            hamps = np.array(obgrp["amplitudes"])
+            hhits = np.array(obgrp["hits"])
+            hflags = np.array(obgrp["flags"])
             n_bin = hamps.shape[1]
+            bad = hflags != 0
+            hamps[bad] = np.nan
 
             for idet, det in enumerate(det_list):
                 outfile = f"{out_root}_{obname}_{det}.pdf"

src/toast/tests/CMakeLists.txt

@@ -78,5 +78,6 @@ install(FILES
     ops_signal_diff_noise.py
     ops_loader.py
     accelerator.py
+    ops_example_ground.py
     DESTINATION ${PYTHON_SITE}/toast/tests
 )