diff --git a/ixmp/tests/core/test_meta.py b/ixmp/tests/core/test_meta.py
index da3b03cd2..c2c02f8d3 100644
--- a/ixmp/tests/core/test_meta.py
+++ b/ixmp/tests/core/test_meta.py
@@ -7,9 +7,9 @@
 from ixmp.testing import models
 
 
-sample_meta = {'sample_int': 3, 'sample_string': 'string_value',
+SAMPLE_META = {'sample_int': 3, 'sample_string': 'string_value',
                'sample_bool': False}
-meta_entries = [
+META_ENTRIES = [
     {'sample_int': 3},
     {'sample_string': 'string_value'},
     {'sample_bool': False},
@@ -20,106 +20,106 @@
     },
     {'mixed_category': ['string', 0.01, 2, True]},
 ]
-dantzig = models['dantzig']
+DANTZIG = models['dantzig']
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_set_meta_missing_argument(mp, meta):
     with pytest.raises(ValueError):
         mp.set_meta(meta)
     with pytest.raises(ValueError):
-        mp.set_meta(meta, model=dantzig['model'], version=0)
+        mp.set_meta(meta, model=DANTZIG['model'], version=0)
     with pytest.raises(ValueError):
-        mp.set_meta(meta, scenario=dantzig['scenario'], version=0)
+        mp.set_meta(meta, scenario=DANTZIG['scenario'], version=0)
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_set_get_meta(mp, meta):
     """Assert that storing+retrieving meta yields expected values"""
-    mp.set_meta(meta, model=dantzig['model'])
-    obs = mp.get_meta(model=dantzig['model'])
+    mp.set_meta(meta, model=DANTZIG['model'])
+    obs = mp.get_meta(model=DANTZIG['model'])
     assert obs == meta
     assert obs == mp.get_meta()
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_unique_meta(mp, meta):
     """
     When setting a meta key on two levels, a uniqueness error is expected.
     """
-    scenario = ixmp.Scenario(mp, **dantzig, version='new')
+    scenario = ixmp.Scenario(mp, **DANTZIG, version='new')
     scenario.commit('save dummy scenario')
-    mp.set_meta(meta, model=dantzig['model'])
+    mp.set_meta(meta, model=DANTZIG['model'])
     expected = ("Metadata already contains category")
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, **dantzig, version=scenario.version)
-    scen = ixmp.Scenario(mp, **dantzig)
+        mp.set_meta(meta, **DANTZIG, version=scenario.version)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     with pytest.raises(Exception, match=expected):
         scen.set_meta(meta)
     # changing the category value type still should raise an error
     meta = {'sample_entry': 3}
-    mp.set_meta(meta, **dantzig)
+    mp.set_meta(meta, **DANTZIG)
     meta['sample_entry'] = 'test-string'
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, **dantzig, version=scenario.version)
+        mp.set_meta(meta, **DANTZIG, version=scenario.version)
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_unique_meta_differing_model(mp, meta):
     """
     When meta is set on a model-level, setting it on a new model and a scenario
     should fail.
     """
-    mp.set_meta(meta, model=dantzig['model'])
-    dantzig2 = {
+    mp.set_meta(meta, model=DANTZIG['model'])
+    DANTZIG2 = {
         'model': 'canning problem 2',
         'scenario': 'standard',
     }
-    mp.add_model(dantzig2['model'])
+    mp.add_model(DANTZIG2['model'])
     expected = "Metadata already contains category"
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, **dantzig2)
+        mp.set_meta(meta, **DANTZIG2)
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_unique_meta_model_scenario(mp, meta):
     """
     When setting a meta key for a Model, it shouldn't be possible to set it
     for a Model+Scenario then.
     """
-    mp.set_meta(meta, model=dantzig['model'])
+    mp.set_meta(meta, model=DANTZIG['model'])
     expected = "Metadata already contains category"
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, **dantzig)
+        mp.set_meta(meta, **DANTZIG)
 
 
-@pytest.mark.parametrize('meta', meta_entries)
+@pytest.mark.parametrize('meta', META_ENTRIES)
 def test_unique_meta_scenario(mp, meta):
     """
     When setting a meta key on a specific Scenario run, setting the same key
     on an higher level (Model or Model+Scenario) should fail.
     """
-    scen = ixmp.Scenario(mp, **dantzig)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     scen.set_meta(meta)
     # add a second scenario and verify that setting Meta for it works
-    scen2 = ixmp.Scenario(mp, **dantzig, version="new")
+    scen2 = ixmp.Scenario(mp, **DANTZIG, version="new")
     scen2.commit('save dummy scenario')
     scen2.set_meta(meta)
     assert scen2.get_meta() == scen.get_meta()
 
     expected = ("Metadata already contains category")
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, **dantzig)
+        mp.set_meta(meta, **DANTZIG)
     with pytest.raises(Exception, match=expected):
-        mp.set_meta(meta, model=dantzig['model'])
+        mp.set_meta(meta, model=DANTZIG['model'])
 
 
 def test_meta_partial_overwrite(mp):
     meta1 = {'sample_string': 3.0, 'another_string': 'string_value',
-            'sample_bool': False}
+             'sample_bool': False}
     meta2 = {'sample_string': 5.0, 'yet_another_string': 'hello',
              'sample_bool': True}
-    scen = ixmp.Scenario(mp, **dantzig)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     scen.set_meta(meta1)
     scen.set_meta(meta2)
     expected = copy.copy(meta1)
@@ -131,11 +131,11 @@ def test_meta_partial_overwrite(mp):
 def test_remove_meta(mp):
     meta = {'sample_int': 3.0, 'another_string': 'string_value'}
     remove_key = 'another_string'
-    mp.set_meta(meta, **dantzig)
-    mp.remove_meta(remove_key, **dantzig)
+    mp.set_meta(meta, **DANTZIG)
+    mp.remove_meta(remove_key, **DANTZIG)
     expected = copy.copy(meta)
     del expected[remove_key]
-    obs = mp.get_meta(**dantzig)
+    obs = mp.get_meta(**DANTZIG)
     assert expected == obs
 
 
@@ -144,13 +144,13 @@ def test_remove_invalid_meta(mp):
     Removing nonexisting meta entries or None shouldn't result in any meta
     being removed. Providing None should give a ValueError.
     """
-    mp.set_meta(sample_meta, **dantzig)
+    mp.set_meta(SAMPLE_META, **DANTZIG)
     with pytest.raises(ValueError):
-        mp.remove_meta(None, **dantzig)
-    mp.remove_meta('nonexisting_category', **dantzig)
-    mp.remove_meta([], **dantzig)
-    obs = mp.get_meta(**dantzig)
-    assert obs == sample_meta
+        mp.remove_meta(None, **DANTZIG)
+    mp.remove_meta('nonexisting_category', **DANTZIG)
+    mp.remove_meta([], **DANTZIG)
+    obs = mp.get_meta(**DANTZIG)
+    assert obs == SAMPLE_META
 
 
 def test_set_and_remove_meta_scenario(mp):
@@ -161,7 +161,7 @@ def test_set_and_remove_meta_scenario(mp):
     meta2 = {'sample_string': 5.0, 'yet_another_string': 'hello'}
     remove_key = 'another_string'
 
-    scen = ixmp.Scenario(mp, **dantzig)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     scen.set_meta(meta1)
     scen.set_meta(meta2)
     expected = copy.copy(meta1)
@@ -181,7 +181,7 @@ def test_scenario_delete_meta_warning(mp):
 
     This test can be removed once Scenario.delete_meta is removed.
     """
-    scen = ixmp.Scenario(mp, **dantzig)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     meta = {'sample_int': 3, 'sample_string': 'string_value'}
     remove_key = 'sample_string'
 
@@ -197,10 +197,10 @@ def test_scenario_delete_meta_warning(mp):
 def test_meta_arguments(mp):
     """Set scenario meta with key-value arguments"""
     meta = {'sample_int': 3}
-    scen = ixmp.Scenario(mp, **dantzig)
+    scen = ixmp.Scenario(mp, **DANTZIG)
     scen.set_meta(meta)
     # add a second scenario and verify that setting Meta for it works
-    scen2 = ixmp.Scenario(mp, **dantzig, version="new")
+    scen2 = ixmp.Scenario(mp, **DANTZIG, version="new")
     scen2.commit('save dummy scenario')
     scen2.set_meta(*meta.popitem())
     assert scen.get_meta() == scen2.get_meta()
@@ -208,20 +208,20 @@ def test_meta_arguments(mp):
 
 def test_update_meta_lists(mp):
     """Set metadata categories having list/array values"""
-    sample_meta = {'list_category': ['a', 'b', 'c']}
-    mp.set_meta(sample_meta, model=dantzig['model'])
-    obs = mp.get_meta(model=dantzig['model'])
-    assert obs == sample_meta
+    SAMPLE_META = {'list_category': ['a', 'b', 'c']}
+    mp.set_meta(SAMPLE_META, model=DANTZIG['model'])
+    obs = mp.get_meta(model=DANTZIG['model'])
+    assert obs == SAMPLE_META
     # try updating meta
-    sample_meta = {'list_category': ['a', 'e', 'f']}
-    mp.set_meta(sample_meta, model=dantzig['model'])
-    obs = mp.get_meta(model=dantzig['model'])
-    assert obs == sample_meta
+    SAMPLE_META = {'list_category': ['a', 'e', 'f']}
+    mp.set_meta(SAMPLE_META, model=DANTZIG['model'])
+    obs = mp.get_meta(model=DANTZIG['model'])
+    assert obs == SAMPLE_META
 
 
 def test_meta_mixed_list(mp):
     """Set metadata categories having list/array values"""
     meta = {'mixed_category': ['string', 0.01, True]}
-    mp.set_meta(meta, model=dantzig['model'])
-    obs = mp.get_meta(model=dantzig['model'])
+    mp.set_meta(meta, model=DANTZIG['model'])
+    obs = mp.get_meta(model=DANTZIG['model'])
     assert obs == meta