python/tests: Tweak writer test to fail with 64-bit long double.

If digital_rf is compiled to use 64-bit long double values (as opposed
to 80-bit or more), or other compiler flags throw off the long double
sample rate math, users are likely to see write failures depending on
the sample rate. Usually this results in an error message of
"Failed to write data" and "Request index M before first expected
index N".

The current Python tests don't trigger this condition, so they pass when
using 64-bit long doubles. This commit tweaks the file cadence so that
the write error is triggered in these cases, so we can be forewarned
that errors are likely when writing under those compilation conditions.

python/tests/test_digital_rf_hdf5.py

@@ -127,9 +127,9 @@ def hdf_filter_params(request):
     scope="session",
     params=[
         # srnum, srden, sdcsec, fcms
-        (200, 3, 10, 1000)
+        (200, 3, 2, 400)
     ],
-    ids=["200/3hz,10s,1000ms"],
+    ids=["200/3hz,2s,400ms"],
 )
 def sample_params(request):
     return dict(
@@ -361,21 +361,14 @@ def data_file_list(sample_params):
     # get params as a tuple of values sorted in key order
     params = tuple(v for k, v in sorted(sample_params.items()))
     file_lists = {
-        (1000, 3, 200, 10): [
+        (400, 3, 200, 2): [
             os.path.join("2014-03-09T12-30-30", "rf@1394368230.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368231.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368232.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368233.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368234.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368236.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368237.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368238.000.h5"),
-            os.path.join("2014-03-09T12-30-30", "rf@1394368239.000.h5"),
-            os.path.join("2014-03-09T12-30-40", "rf@1394368240.000.h5"),
-            os.path.join("2014-03-09T12-30-40", "rf@1394368241.000.h5"),
-            os.path.join("2014-03-09T12-30-40", "rf@1394368242.000.h5"),
-            os.path.join("2014-03-09T12-30-40", "rf@1394368243.000.h5"),
-            os.path.join("2014-03-09T12-30-40", "rf@1394368244.000.h5"),
+            os.path.join("2014-03-09T12-30-30", "rf@1394368230.400.h5"),
+            os.path.join("2014-03-09T12-30-30", "rf@1394368230.800.h5"),
+            os.path.join("2014-03-09T12-30-30", "rf@1394368231.200.h5"),
+            os.path.join("2014-03-09T12-30-30", "rf@1394368231.600.h5"),
+            os.path.join("2014-03-09T12-30-32", "rf@1394368232.400.h5"),
+            os.path.join("2014-03-09T12-30-32", "rf@1394368232.800.h5"),
         ]
     }
     return file_lists[params]
@@ -685,7 +678,7 @@ def test_writer_write_blocks(
                 global_sample_arr=global_sample_arr,
                 block_sample_arr=block_sample_arr,
             )
-            assert next_rel_index == (block_stops[-1] - bounds[0])
+            assert next_rel_index == (block_stops[-1] - start_global_index)
 
             # fail with non-matching length of sample lists
             with pytest.raises(ValueError):