Pytest enhancements

Adds

1. A pytest marker generate that marks a test as generating test data. These tests will only be run when the --generate flag is given, and all other tests won't be run in this case. This prevents accidentally overwriting test data.
2. A pytest fixture compare_noise which checks whether all noises in a budget are the same as in another budget. A list of noises passing, failing, or skipped is printed and an assertion error is raised if any traces are different.

The unit tests test_save_budgets and test_check_noise are added to test/budgets/test_budgets.py making use of the new fixture and marker. The compare_noise fixture is useful because it quickly checks if noises are the same and fails if any are different. So you can have pytest both continuously plotting a budget and quickly checking if any noises have changed by doing for example

ptw -- test/budgets/test_budgets.py -s -k test_check_noise
ptw -- test/budgets/test_budgets.py -s -k test_load[Aplus]

test/budgets/test_budgets.py

@@ -3,17 +3,36 @@
 import numpy as np
 import gwinc
 from gwinc import load_budget
+import gwinc.io as io
 from copy import deepcopy
 import pytest
 
 
-def test_load(pprint, tpath_join, fpath_join):
-    pprint(gwinc.IFOS)
-    for ifo in gwinc.IFOS:
-        B = load_budget(ifo)
-        trace = B.run()
-        fig = trace.plot()
-        fig.savefig(tpath_join('budget_{}.pdf'.format(ifo)))
+@pytest.mark.parametrize("ifo", gwinc.IFOS)
+def test_load(ifo, pprint, tpath_join, fpath_join):
+    B = load_budget(ifo)
+    trace = B.run()
+    fig = trace.plot()
+    fig.savefig(tpath_join('budget_{}.pdf'.format(ifo)))
+
+
+@pytest.mark.generate
+@pytest.mark.parametrize("ifo", gwinc.IFOS)
+def test_save_budgets(ifo, fpath_join):
+    B = load_budget(ifo)
+    traces = B.run()
+    io.save_hdf5(traces, fpath_join(ifo + '.h5'))
+
+
+@pytest.mark.parametrize("ifo", gwinc.IFOS)
+def test_check_noise(ifo, fpath_join, compare_noise):
+    try:
+        ref_traces = io.load_hdf5(fpath_join(ifo + '.h5'))
+    except OSError:
+        return
+    budget = load_budget(ifo, freq=ref_traces.freq)
+    traces = budget.run()
+    compare_noise(traces, ref_traces)
 
 
 @pytest.mark.logic