diff --git a/tests/unit_tests/test_data_neutron.py b/tests/unit_tests/test_data_neutron.py
index 03746430d9..a412f2024c 100644
--- a/tests/unit_tests/test_data_neutron.py
+++ b/tests/unit_tests/test_data_neutron.py
@@ -96,6 +96,18 @@ def am244():
     endf_file = os.path.join(_ENDF_DATA, 'neutrons', 'n-095_Am_244.endf')
     return openmc.data.IncidentNeutron.from_njoy(endf_file)
 
+@pytest.fixture(scope='module')
+def gd154cov():
+    """Gd154 ENDF data (contains Reich Moore resonance range)"""
+    filename = os.path.join(_ENDF_DATA, 'neutrons', 'n-064_Gd_154.endf')
+    return openmc.data.IncidentNeutron.from_endf(filename, get_covariance=True)
+
+@pytest.fixture(scope='module')
+def ti50():
+    """Ti50 ENDF data (contains Multi-level Breit-Wigner resonance range)"""
+    filename = os.path.join(_ENDF_DATA, 'neutrons', 'n-022_Ti_050.endf')
+    return openmc.data.IncidentNeutron.from_endf(filename, get_covariance=True)
+
 
 def test_attributes(pu239):
     assert pu239.name == 'Pu239'
@@ -243,6 +255,29 @@ def test_mlbw(sm150):
     assert sorted(xs.keys()) == [2, 18, 102]
     assert np.all(xs[18] == 0.0)
 
+#FIXME
+def test_mlbw_cov(ti50):
+    #Testing on first range
+    cov = ti50.res_covariance.ranges[0]
+    res = ti50.resonances.ranges[0]
+    assert cov.parameters['energy'][0] == pytest.approx(-21020.)
+    assert res.parameters['energy'][0] == cov.parameters['energy'][0]
+    assert isinstance(cov, openmc.data.resonance_covariance.MultiLevelBreitWignerCovariance)
+    assert cov.energy_min == pytest.approx(1e-5)
+    assert cov.energy_max == pytest.approx(587000.)
+    assert cov.covariance[0,0] == pytest.approx(1.410177e5)
+
+    cov.res_subset('L',[1,1])
+    subset = cov.parameters_subset
+    assert not subset.empty
+    assert cov.cov_subset is not None
+    assert (subset['L'] == 1).all()
+    cov.sample_resonance_parameters(1)
+    xs = cov.reconstruct([10., 100., 1000.], res, 0)
+    assert sorted(xs.keys()) == [2, 18, 102]
+
+#FIXME
+
 
 def test_reichmoore(gd154):
     res = gd154.resonances