1 files changed, 51 insertions, 0 deletions
diff --git a/tests/test_addnodes.py b/tests/test_addnodes.py
new file mode 100644
index 0000000..184a696
--- /dev/null
+++ b/tests/test_addnodes.py
@@ -0,0 +1,51 @@
+"""Test the non-trivial features in the :mod:`sphinx.addnodes` module."""
+
+from __future__ import annotations
+
+import pytest
+
+from sphinx import addnodes
+
+
+@pytest.fixture()
+def sig_elements() -> set[type[addnodes.desc_sig_element]]:
+    """Fixture returning the current ``addnodes.SIG_ELEMENTS`` set."""
+    original = addnodes.SIG_ELEMENTS.copy()  # safe copy of the current nodes
+    yield {*addnodes.SIG_ELEMENTS}  # temporary value to use during tests
+    addnodes.SIG_ELEMENTS = original  # restore the previous value
+
+
+def test_desc_sig_element_nodes(sig_elements):
+    """Test the registration of ``desc_sig_element`` subclasses."""
+
+    # expected desc_sig_* node classes (must be declared *after* reloading
+    # the module since otherwise the objects are not the correct ones)
+    EXPECTED_SIG_ELEMENTS = {
+        addnodes.desc_sig_space,
+        addnodes.desc_sig_name,
+        addnodes.desc_sig_operator,
+        addnodes.desc_sig_punctuation,
+        addnodes.desc_sig_keyword,
+        addnodes.desc_sig_keyword_type,
+        addnodes.desc_sig_literal_number,
+        addnodes.desc_sig_literal_string,
+        addnodes.desc_sig_literal_char,
+    }
+
+    assert addnodes.SIG_ELEMENTS == EXPECTED_SIG_ELEMENTS
+
+    # create a built-in custom desc_sig_element (added to SIG_ELEMENTS)
+    class BuiltInSigElementLikeNode(addnodes.desc_sig_element, _sig_element=True):
+        pass
+
+    # create a custom desc_sig_element (implicitly not added to SIG_ELEMENTS)
+    class Custom1SigElementLikeNode(addnodes.desc_sig_element):
+        pass
+
+    # create a custom desc_sig_element (explicitly not added to SIG_ELEMENTS)
+    class Custom2SigElementLikeNode(addnodes.desc_sig_element, _sig_element=False):
+        pass
+
+    assert BuiltInSigElementLikeNode in addnodes.SIG_ELEMENTS
+    assert Custom1SigElementLikeNode not in addnodes.SIG_ELEMENTS
+    assert Custom2SigElementLikeNode not in addnodes.SIG_ELEMENTS