Add TagSpec read-name contract tests

Author: AndrewSazonov

tests/unit/easydiffraction/io/cif/test_handler.py

@@ -33,3 +33,47 @@ def test_tags_cif_name_uses_explicit_value():
     )
 
     assert handler.cif_name == '_easydiffraction_calculator.type'
+
+
+def test_explicit_edi_name_overrides_first_and_leads_read_order():
+    from easydiffraction.io.cif.handler import TagSpec
+
+    handler = TagSpec(edi_names=['_a.x', '_a.y'], edi_name='_a.z')
+
+    assert handler.edi_name == '_a.z'
+    assert handler.edi_read_names == ['_a.z', '_a.x', '_a.y']
+
+
+def test_edi_read_names_remove_duplicates():
+    from easydiffraction.io.cif.handler import TagSpec
+
+    handler = TagSpec(edi_names=['_a.x', '_a.x'])
+
+    assert handler.edi_read_names == ['_a.x']
+
+
+def test_cif_read_names_dedup_and_canonical_first():
+    from easydiffraction.io.cif.handler import TagSpec
+
+    handler = TagSpec(edi_names=['_a.x'], cif_names=['_b.y', '_b.z', '_b.y'])
+
+    assert handler.cif_name == '_b.y'
+    assert handler.cif_read_names == ['_b.y', '_b.z']
+
+
+def test_cif_names_default_to_edi_names():
+    from easydiffraction.io.cif.handler import TagSpec
+
+    handler = TagSpec(edi_names=['_a.x'])
+
+    assert handler.cif_names == ['_a.x']
+    assert handler.cif_name == '_a.x'
+
+
+def test_read_names_union_orders_edi_before_cif_and_dedupes():
+    from easydiffraction.io.cif.handler import TagSpec
+
+    handler = TagSpec(edi_names=['_a.x'], cif_names=['_a.x', '_b.y'])
+
+    # Edi name first, then CIF-only aliases, with duplicates removed.
+    assert handler.read_names == ['_a.x', '_b.y']