Merge pull request #1095 from davep/mount-relative

Add support for mounting widgets relative to other widgets

tests/test_node_list.py

@@ -1,3 +1,5 @@
+import pytest
+
 from textual.widget import Widget
 from textual._node_list import NodeList
 
@@ -19,6 +21,16 @@ def test_repeat_add_one():
         nodes._append(widget)
     assert len(nodes)==1
 
+def test_insert():
+    nodes = NodeList()
+    widget1 = Widget()
+    widget2 = Widget()
+    widget3 = Widget()
+    nodes._append(widget1)
+    nodes._append(widget3)
+    nodes._insert(1,widget2)
+    assert list(nodes) == [widget1,widget2,widget3]
+
 def test_truthy():
     """Does a node list act as a truthy object?"""
     nodes = NodeList()
@@ -35,6 +47,15 @@ def test_contains():
     assert widget in nodes
     assert Widget() not in nodes
 
+def test_index():
+    """Can we get the index of a widget in the list?"""
+    widget = Widget()
+    nodes = NodeList()
+    with pytest.raises(ValueError):
+        _ = nodes.index(widget)
+    nodes._append(widget)
+    assert nodes.index(widget) == 0
+
 def test_remove():
     """Can we remove a widget we've added?"""
     widget = Widget()

tests/test_widget_mount_point.py

@@ -0,0 +1,40 @@
+import pytest
+
+from textual.widget import Widget
+
+
+class Content(Widget):
+    pass
+
+
+class Body(Widget):
+    pass
+
+
+def test_find_dom_spot():
+
+    # Build up a "fake" DOM for an application.
+    screen = Widget(name="Screen")
+    header = Widget(name="Header", id="header")
+    body = Body(id="body")
+    content = [Content(id=f"item{n}") for n in range(1000)]
+    body._add_children(*content)
+    footer = Widget(name="Footer", id="footer")
+    screen._add_children(header, body, footer)
+
+    # Just as a quick double-check, make sure the main components are in
+    # their intended place.
+    assert list(screen.children) == [header, body, footer]
+
+    # Now check that we find what we're looking for in the places we expect
+    # to find them.
+    assert screen._find_mount_point(1) == (screen, 1)
+    assert screen._find_mount_point(body) == screen._find_mount_point(1)
+    assert screen._find_mount_point("Body") == screen._find_mount_point(body)
+    assert screen._find_mount_point("#body") == screen._find_mount_point(1)
+
+    # Finally, let's be sure that we get an error if, for some odd reason,
+    # we go looking for a widget that isn't actually part of the DOM we're
+    # looking in.
+    with pytest.raises(Widget.MountError):
+        _ = screen._find_mount_point(Widget())

tests/test_widget_mounting.py

@@ -0,0 +1,113 @@
+import pytest
+
+from textual.app import App
+from textual.widgets import Static
+
+async def test_mount_via_app() -> None:
+    """Perform mount tests via the app."""
+
+    # Make a background set of widgets.
+    widgets = [Static(id=f"starter-{n}") for n in range( 10 )]
+
+    async with App().run_test() as pilot:
+        # Mount the first one and make sure it's there.
+        await pilot.app.mount(widgets[0])
+        assert len(pilot.app.screen.children) == 1
+        assert pilot.app.screen.children[0] == widgets[0]
+
+        # Mount the next 2 widgets via mount.
+        await pilot.app.mount(*widgets[1:3])
+        assert list(pilot.app.screen.children) == widgets[0:3]
+
+        # Finally mount the rest of the widgets via mount_all.
+        await pilot.app.mount_all(widgets[3:])
+        assert list(pilot.app.screen.children) == widgets
+
+    async with App().run_test() as pilot:
+        # Mount a widget before -1, which is "before the end".
+        penultimate = Static(id="penultimate")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(penultimate, before=-1)
+        assert pilot.app.screen.children[-2] == penultimate
+
+    async with App().run_test() as pilot:
+        # Mount a widget after -1, which is "at the end".
+        ultimate = Static(id="ultimate")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(ultimate, after=-1)
+        assert pilot.app.screen.children[-1] == ultimate
+
+    async with App().run_test() as pilot:
+        # Mount a widget before -2, which is "before the penultimate".
+        penpenultimate = Static(id="penpenultimate")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(penpenultimate, before=-2)
+        assert pilot.app.screen.children[-3] == penpenultimate
+
+    async with App().run_test() as pilot:
+        # Mount a widget after -2, which is "before the end".
+        penultimate = Static(id="penultimate")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(penultimate, after=-2)
+        assert pilot.app.screen.children[-2] == penultimate
+
+    async with App().run_test() as pilot:
+        # Mount a widget before 0, which is "at the start".
+        start = Static(id="start")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(start, before=0)
+        assert pilot.app.screen.children[0] == start
+
+    async with App().run_test() as pilot:
+        # Mount a widget after 0. You get the idea...
+        second = Static(id="second")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(second, after=0)
+        assert pilot.app.screen.children[1] == second
+
+    async with App().run_test() as pilot:
+        # Mount a widget relative to another via query.
+        queue_jumper = Static(id="queue-jumper")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(queue_jumper, after="#starter-5")
+        assert pilot.app.screen.children[6] == queue_jumper
+
+    async with App().run_test() as pilot:
+        # Mount a widget relative to another via query.
+        queue_jumper = Static(id="queue-jumper")
+        await pilot.app.mount_all(widgets)
+        await pilot.app.mount(queue_jumper, after=widgets[5])
+        assert pilot.app.screen.children[6] == queue_jumper
+
+    async with App().run_test() as pilot:
+        # Make sure we get told off for trying to before and after.
+        await pilot.app.mount_all(widgets)
+        with pytest.raises(Static.MountError):
+            await pilot.app.mount(Static(), before=2, after=2)
+
+    async with App().run_test() as pilot:
+        # Make sure we get told off trying to mount relative to something
+        # that isn't actually in the DOM.
+        await pilot.app.mount_all(widgets)
+        with pytest.raises(Static.MountError):
+            await pilot.app.mount(Static(), before=Static())
+        with pytest.raises(Static.MountError):
+            await pilot.app.mount(Static(), after=Static())
+
+    # TODO: At the moment query_one() simply takes a query and returns the
+    # .first() item. As such doing a query_one() that gets more than one
+    # thing isn't an error, it just skims off the first thing. OTOH the
+    # intention of before= and after= with a selector is that an exception
+    # will be thrown -- the exception being the own that should be thrown
+    # from query_one(). So, this test here is a TODO test because we'll wait
+    # for a change to query_one() and then its exception will just bubble
+    # up.
+    #
+    # See https://github.com/Textualize/textual/issues/1096
+    #
+    # async with App().run_test() as pilot:
+    #     # Make sure we get an error if we try and mount with a selector that
+    #     # results in more than one hit.
+    #     await pilot.app.mount_all(widgets)
+    #     with pytest.raises( ?Something? ):
+    #         await pilot.app.mount(Static(), before="Static")