Test duplicate key namespaces

* Cover strict duplicate detection for string blocks.
* Verify entries and strings may share a key without conflict.

Author: claell

tests/test_library.py

@@ -4,6 +4,7 @@
 from bibtexparser.model import Entry
 from bibtexparser.model import Field
 from bibtexparser.model import ImplicitComment
+from bibtexparser.model import String
 
 
 def get_dummy_entry():
@@ -17,6 +18,10 @@ def get_dummy_entry():
     )
 
 
+def get_dummy_string():
+    return String(key="duplicateKey", value='"A value"')
+
+
 def test_replace_with_duplicates():
     """Test that replace() works when there are duplicate values. See issue 404."""
     library = Library()
@@ -97,6 +102,26 @@ def test_constructor_fails_on_duplicate_by_default():
     assert len(library.failed_blocks) == 1
 
 
+def test_add_string_fails_on_duplicate_by_default():
+    """Strict duplicate handling applies to string blocks as well as entries."""
+    library = Library(blocks=[get_dummy_string()])
+
+    with pytest.raises(ValueError, match="duplicateKey"):
+        library.add(get_dummy_string())
+
+    assert len(library.strings) == 1
+    assert len(library.failed_blocks) == 0
+
+
+def test_entry_and_string_keys_use_separate_namespaces():
+    """An entry and string may share a key without becoming duplicate blocks."""
+    library = Library(blocks=[get_dummy_entry(), get_dummy_string()])
+
+    assert len(library.entries) == 1
+    assert len(library.strings) == 1
+    assert len(library.failed_blocks) == 0
+
+
 def test_remove_prefers_identical_instance_over_equal_block():
     """With two equal blocks, remove() must remove the passed instance. See issue 537."""
     first_comment = ImplicitComment("#same")