PseudoPotentialData: add the get_entry_point_name classmethod (#30)

The method will return the entry point name under which the subclass of
`PseudoPotentialData` is registered. Note that the entry point name does
not include the entry point group. For example, the `UpfData` plugin is
registered under `aiida.data:pseudo.upf`, but the classmethod will
return the string `pseudo.upf`.

aiida_pseudo/data/pseudo/pseudo.py

@@ -18,6 +18,16 @@ class PseudoPotentialData(SingleFileData):
     _key_element = 'element'
     _key_md5 = 'md5'
 
+    @classmethod
+    def get_entry_point_name(cls):
+        """Return the entry point name associated with this data class.
+
+        :return: the entry point name.
+        """
+        from aiida.plugins.entry_point import get_entry_point_from_class
+        _, entry_point = get_entry_point_from_class(cls.__module__, cls.__name__)
+        return entry_point.name
+
     @classmethod
     def validate_element(cls, element: str):
         """Validate the given element symbol.

tests/data/pseudo/test_common.py

@@ -0,0 +1,30 @@
+# -*- coding: utf-8 -*-
+# pylint: disable=redefined-outer-name
+"""Tests that are common to all data plugins in the :py:mod:`~aiida_pseudo.data.pseudo` module."""
+import pytest
+
+from aiida import plugins
+
+
+def get_entry_point_names():
+    """Return the registered entry point names for the given common workflow.
+
+    :param workflow: the name of the common workflow.
+    :param leaf: if True, only return the leaf of the entry point name, i.e., the name of plugin that implements it.
+    :return: list of entry points names.
+    """
+    prefix = 'pseudo.'
+    entry_points_names = plugins.entry_point.get_entry_point_names('aiida.data')
+    return [name for name in entry_points_names if name.startswith(prefix)]
+
+
+@pytest.fixture(scope='function', params=get_entry_point_names())
+def entry_point_name(request):
+    """Fixture that parametrizes over all the registered subclass implementations of ``PseudoPotentialData``."""
+    return request.param
+
+
+def test_get_entry_point_name(entry_point_name):
+    """Test the ``PseudoPotentialData.get_entry_point_name`` method."""
+    cls = plugins.DataFactory(entry_point_name)
+    assert cls.get_entry_point_name() == entry_point_name