def test_datasets_stack_reduce():
obs_ids = [23523, 23526, 23559, 23592]
dataset_list = []
for obs in obs_ids:
filename = "$GAMMAPY_DATA/joint-crab/spectra/hess/pha_obs{}.fits"
ds = SpectrumDatasetOnOff.from_ogip_files(filename.format(obs))
dataset_list.append(ds)
datasets = Datasets(dataset_list)
stacked = datasets.stack_reduce()
assert_allclose(stacked.livetime.to_value("s"), 6313.8116406202325)
info_table = datasets.info_table()
assert_allclose(info_table["n_on"], [124, 126, 119, 90])
info_table_cum = datasets.info_table(cumulative=True)
assert_allclose(info_table_cum["n_on"], [124, 250, 369, 459])
# ## Source statistic
#
# Next we're going to look at the overall source statistics in our signal region.
# In[ ]:
datasets_all = Datasets(datasets)
# In[ ]:
info_table = datasets_all.info_table(cumulative=True)
# In[ ]:
info_table
# In[ ]:
plt.plot(
info_table["livetime"].to("h"), info_table["excess"], marker="o", ls="none"
)
plt.xlabel("Livetime [h]")