Allow nodes in shadow roots to be addressed via Element (#1454)

pyscriptjs/tests/integration/test_shadow_root.py

@@ -0,0 +1,30 @@
+from .support import PyScriptTest, skip_worker
+
+
+class TestShadowRoot(PyScriptTest):
+    @skip_worker("FIXME: js.document")
+    def test_reachable_shadow_root(self):
+        self.pyscript_run(
+            r"""
+            <script>
+                // reason to wait for py-script is that it's the entry point for
+                // all patches and the MutationObserver, otherwise being this a synchronous
+                // script the constructor gets instantly invoked at the node before
+                // py-script gets a chance to initialize itself.
+                customElements.whenDefined('py-script').then(() => {
+                    customElements.define('s-r', class extends HTMLElement {
+                      constructor() {
+                        super().attachShadow({mode: 'closed'}).innerHTML =
+                            '<div id="shadowed">OK</div>';
+                      }
+                  });
+                });
+            </script>
+            <s-r></s-r>
+            <py-script>
+                import js
+                js.console.log(Element("shadowed").innerHtml)
+            </py-script>
+            """
+        )
+        assert self.console.log.lines[-1] == "OK"