tests

tests/test_count_parameters.py

@@ -0,0 +1,57 @@
+from functools import partial
+
+from textual._callback import count_parameters
+
+
+def test_functions() -> None:
+    """Test count parameters of functions."""
+
+    def foo(): ...
+    def bar(a): ...
+    def baz(a, b): ...
+
+    # repeat to allow for caching
+    for _ in range(3):
+        assert count_parameters(foo) == 0
+        assert count_parameters(bar) == 1
+        assert count_parameters(baz) == 2
+
+
+def test_methods() -> None:
+    """Test count parameters of methods."""
+
+    class Foo:
+        def foo(self): ...
+        def bar(self, a): ...
+        def baz(self, a, b): ...
+
+    foo = Foo()
+
+    # repeat to allow for caching
+    for _ in range(3):
+        assert count_parameters(foo.foo) == 0
+        assert count_parameters(foo.bar) == 1
+        assert count_parameters(foo.baz) == 2
+
+
+def test_partials() -> None:
+    """Test count parameters of partials."""
+
+    class Foo:
+        def method(self, a, b, c, d): ...
+
+    foo = Foo()
+
+    partial0 = partial(foo.method)
+    partial1 = partial(foo.method, 10)
+    partial2 = partial(foo.method, b=10, c=20)
+
+    for _ in range(3):
+        assert count_parameters(partial0) == 4
+        assert count_parameters(partial0) == 4
+
+        assert count_parameters(partial1) == 3
+        assert count_parameters(partial1) == 3
+
+        assert count_parameters(partial2) == 2
+        assert count_parameters(partial2) == 2

tests/test_gc.py

@@ -0,0 +1,87 @@
+import asyncio
+import gc
+
+import pytest
+
+from textual.app import App, ComposeResult
+from textual.containers import Vertical
+from textual.widgets import Footer, Header, Label
+
+
+def count_nodes() -> int:
+    """Count number of references to DOMNodes."""
+    dom_nodes = [
+        obj
+        for obj in gc.get_objects()
+        if any(cls.__name__ == "DOMNode" for cls in obj.__class__.__mro__)
+    ]
+    print(dom_nodes)
+    return len(dom_nodes)
+
+
+async def run_app() -> None:
+    """Run a dummy app."""
+
+    class DummyApp(App):
+        """Dummy app with a few widgets."""
+
+        def compose(self) -> ComposeResult:
+            yield Header()
+            with Vertical():
+                yield Label("foo")
+                yield Label("bar")
+            yield Footer()
+
+    app = DummyApp()
+
+    async with app.run_test() as pilot:
+        # We should have a bunch of DOMNodes while the test is running
+        assert count_nodes() > 0
+        await pilot.press("ctrl+c")
+
+    assert not app._running
+
+    # Force a GC collection
+    gc.collect()
+
+    # After the test, all DOMNodes will have been torn down
+    assert count_nodes() == 1
+
+
+async def _count_app_nodes() -> None:
+    """Regression test for https://github.com/Textualize/textual/issues/4959"""
+
+    # Should be no DOMNodes yet
+    assert count_nodes() == 0
+
+    await run_app()
+    await asyncio.sleep(0)
+
+    gc.collect()
+
+    nodes_remaining = count_nodes()
+
+    if nodes_remaining:
+        print("NODES REMAINING")
+
+        import objgraph
+
+        objgraph.show_backrefs(
+            [
+                obj
+                for obj in gc.get_objects()
+                if any(cls.__name__ == "App" for cls in obj.__class__.__mro__)
+            ],
+            filename="graph.png",
+            max_depth=15,
+        )
+
+    assert nodes_remaining == 0
+
+
+# It looks like PyTest holds on to references to DOMNodes
+# So this will only pass if ran in isolation
+@pytest.mark.xfail
+async def test_gc():
+    """Regression test for https://github.com/Textualize/textual/issues/4959"""
+    await _count_app_nodes()