Meta: Implement Platform.remove meta; add tests

- implement Platform.remove_meta
- deprecate Scenario.delete_meta (Scenario.remove_meta should be used)
- add more tests

ixmp/backend/base.py

@@ -921,6 +921,22 @@ def set_meta(self, meta: dict, model: str, scenario: str, version):
             run version that meta should be attached to
         """
 
+    @abstractmethod
+    def remove_meta(self, categories: list, model: str, scenario: str,
+                    version: int):
+        """Remove meta categories.
+
+        Parameters
+        ----------
+        categories : list of str, meta-categories to remove
+        model : str, optional
+            model name that meta should be attached to
+        scenario : str, optional
+            scenario name that meta should be attached to
+        version : int or str, optional
+            run version that meta should be attached to
+        """
+
     @abstractmethod
     def set_scenario_meta(self, s: Scenario, name_or_dict, value=None):
         """Set single or multiple scenario meta entries.
@@ -996,7 +1012,7 @@ def set_scenario_meta(self, s: Scenario, name_or_dict, value=None):
         """
 
     @abstractmethod
-    def delete_scenario_meta(self, s, name):
+    def remove_scenario_meta(self, s, name):
         """Remove single or multiple scenario meta entries.
 
         Parameters

ixmp/backend/jdbc.py

@@ -902,6 +902,17 @@ def set_meta(self, meta: dict, model: str = None, scenario: str = None,
             jmeta.put(str(k), v)
         self.jobj.setMeta(model, scenario, version, jmeta)
 
+    def remove_meta(self, categories, model: str = None, scenario: str = None,
+                    version: int = None):
+        if not (model or scenario or version):
+            msg = ('At least one parameter has to be provided out of: '
+                   'model, scenario, version')
+            raise ValueError(msg)
+        if version is not None:
+            version = java.Long(version)
+        return self.jobj.removeMeta(model, scenario, version,
+                                    to_jlist(categories))
+
     def get_scenario_meta(self, s):
         return {entry.getKey(): _unwrap(entry.getValue())
                 for entry in self.jindex[s].getMeta().entrySet()}
@@ -923,7 +934,11 @@ def set_scenario_meta(self, s, name_or_dict, value=None):
 
         getattr(self.jindex[s], method_name)(name_or_dict, value)
 
-    def delete_scenario_meta(self, s, name):
+    def delete_scenario_meta(self, *args, **kwargs):
+        # Add DeprecationWarning
+        return self.remove_scenario_meta(self, *args, **kwargs)
+
+    def remove_scenario_meta(self, s, name):
         if type(name) == str:
             name = [name]
         jdata = java.LinkedList()

ixmp/core.py

@@ -63,6 +63,7 @@ class Platform:
         'set_doc',
         'get_meta',
         'set_meta',
+        'remove_meta',
     ]
 
     def __init__(self, name=None, backend=None, **backend_args):
@@ -1600,15 +1601,27 @@ def set_meta(self, name_or_dict, value=None):
             name_or_dict = list(name_or_dict.items())
         self._backend('set_scenario_meta', name_or_dict, value)
 
-    def delete_meta(self, name):
-        """Delete scenario meta.
+    def delete_meta(self, *args, **kwargs):
+        """DEPRECATED: Remove scenario meta.
 
         Parameters
         ----------
         name : str or list of str
             Either single meta key or list of keys.
         """
-        self._backend('delete_scenario_meta', name)
+        warn('Scenario.delete_meta is deprecated; use Scenario.remove_meta '
+             'instead', DeprecationWarning)
+        self.remove_meta(*args, **kwargs)
+
+    def remove_meta(self, name):
+        """Remove scenario meta.
+
+        Parameters
+        ----------
+        name : str or list of str
+            Either single meta key or list of keys.
+        """
+        self._backend('remove_scenario_meta', name)
 
     # Input and output
     def to_excel(self, path, items=ItemType.SET | ItemType.PAR, max_row=None):

ixmp/tests/core/test_meta.py

@@ -1,5 +1,6 @@
 """Test meta functionality of ixmp.Platform."""
 
+import copy
 import pytest
 
 import ixmp
@@ -10,17 +11,16 @@
 
 
 def test_set_meta_missing_argument(mp):
-    meta = {'sample_string': 3}
     with pytest.raises(ValueError):
-        mp.set_meta(meta)
+        mp.set_meta(sample_meta)
 
 
-def test_set_meta(mp):
-    meta = {'sample_string': 3}
+def test_set_get_meta(mp):
+    """ASsert that storing+retrieving meta yields expected values"""
     model = models['dantzig']['model']
-    mp.set_meta(meta, model=model)
+    mp.set_meta(sample_meta, model=model)
     obs = mp.get_meta(model=model)
-    assert obs == meta
+    assert obs == sample_meta
 
 
 def test_unique_meta(mp):
@@ -54,14 +54,98 @@ def test_unique_meta_model_scenario(mp):
 def test_unique_meta_scenario(mp):
     """
     When setting a meta key on a specific Scenario run, setting the same key
-    on an higher level should fail too.
+    on an higher level (Model or Model+Scenario) should fail.
     """
     model = models['dantzig']
     scen = ixmp.Scenario(mp, **model)
     scen.set_meta(sample_meta)
+    # add a second scenario and verify that setting Meta for it works
+    scen2 = ixmp.Scenario(mp, **model, version="new")
+    scen2.commit('save dummy scenario')
+    scen2.set_meta(sample_meta)
+    assert scen2.get_meta() == scen.get_meta()
 
     expected = ("Metadata already contains category")
     with pytest.raises(Exception, match=expected):
         mp.set_meta(sample_meta, **model)
     with pytest.raises(Exception, match=expected):
         mp.set_meta(sample_meta, model=model['model'])
+
+
+def test_meta_partial_overwrite(mp):
+    meta1 = {'sample_string': 3.0, 'another_string': 'string_value'}
+    meta2 = {'sample_string': 5.0, 'yet_another_string': 'hello'}
+    model = models['dantzig']
+    scen = ixmp.Scenario(mp, **model)
+    scen.set_meta(meta1)
+    scen.set_meta(meta2)
+    expected = copy.copy(meta1)
+    expected.update(meta2)
+    obs = scen.get_meta()
+    assert obs == expected
+
+
+def test_remove_meta(mp):
+    meta = {'sample_string': 3.0, 'another_string': 'string_value'}
+    remove_key = 'another_string'
+    model = models['dantzig']
+    mp.set_meta(sample_meta, **model)
+    mp.remove_meta(remove_key, **model)
+    expected = copy.copy(meta)
+    del expected[remove_key]
+    obs = mp.get_meta(**model)
+    assert expected == obs
+
+
+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.
+    """
+    model = models['dantzig']
+    mp.set_meta(sample_meta, **model)
+    with pytest.raises(ValueError):
+        mp.remove_meta(None, **model)
+    mp.remove_meta('nonexisting_category', **model)
+    mp.remove_meta([], **model)
+    obs = mp.get_meta(**model)
+    assert obs == sample_meta
+
+
+def test_set_and_remove_meta_scenario(mp):
+    """
+    Test partial overwriting and meta deletion on scenario level
+    """
+    meta1 = {'sample_string': 3.0, 'another_string': 'string_value'}
+    meta2 = {'sample_string': 5.0, 'yet_another_string': 'hello'}
+    remove_key = 'another_string'
+    model = models['dantzig']
+
+    scen = ixmp.Scenario(mp, **model)
+    scen.set_meta(meta1)
+    scen.set_meta(meta2)
+    expected = copy.copy(meta1)
+    expected.update(meta2)
+    obs = scen.get_meta()
+    assert expected == obs
+
+    scen.remove_meta(remove_key)
+    del expected[remove_key]
+    obs = scen.get_meta()
+    assert obs == expected
+
+
+def test_scenario_delete_meta_warning(mp):
+    """Scenario.delete_meta works but raises a deprecation warning"""
+    model = models['dantzig']
+    scen = ixmp.Scenario(mp, **model)
+    meta = {'sample_string': 3, 'another_string': 'string_value'}
+    remove_key = 'another_string'
+
+    scen.set_meta(sample_meta)
+    with pytest.warns(DeprecationWarning):
+        scen.delete_meta(remove_key)
+    expected = copy.copy(meta)
+    del expected[remove_key]
+    obs = scen.get_meta()
+    assert obs == expected