test: Partially migrate annotation test to runtime

Author: abelcheung

tests/runtime/test_annotation.py

@@ -0,0 +1,62 @@
+#
+# This test file attempts to verify function / method annotations are
+# correct, so try NOT to add any type-ignores to this file.
+#
+
+import sys
+
+import pytest
+import typeguard
+from lxml.etree import (
+    LXML_VERSION,
+    Comment,
+    Element,
+    ElementTree,
+    QName as QName,
+    _Element,
+    _ElementTree,
+)
+
+if sys.version_info >= (3, 11):
+    from typing import reveal_type
+else:
+    from typing_extensions import reveal_type
+
+
+class TestElementFactory:
+    # lxml.etree.is_element() exists, but we want to test the
+    # then-factory Element class instead of _Element
+    def _is_element_check(self, el: Element) -> None:
+        reveal_type(el)
+        if LXML_VERSION >= (6, 0, 0):
+            assert isinstance(el, Element)
+        else:
+            assert isinstance(el, _Element)
+        if type(el) is not _Element:
+            # TODO revealtype injector needs to support functiontype
+            with pytest.raises(typeguard.TypeCheckError):
+                reveal_type(el.tag)
+        else:
+            reveal_type(el.tag)
+
+    def test_normal_element(self) -> None:
+        el = Element("test")
+        self._is_element_check(el)
+
+    def test_comment_element(self) -> None:
+        comm = Comment("test")
+        self._is_element_check(comm)
+
+
+class TestElementTreeGeneric:
+    def test_normal_tree(self, xml2_tree: ElementTree) -> None:
+        reveal_type(xml2_tree)
+        if LXML_VERSION >= (6, 0, 0):
+            assert isinstance(xml2_tree, ElementTree)
+        else:
+            assert isinstance(xml2_tree, _ElementTree)
+        # TODO need to write a typeguard plugin to support
+        # checking elements within ElementTree
+
+    # TODO write test to check that ElementTree[int] or other
+    # non-element types are rejected by typeguard