Add test probe and tests for Cocoa Box.

cocoa/src/toga_cocoa/widgets/base.py

@@ -1,3 +1,5 @@
+from abc import abstractmethod
+
 from toga.colors import TRANSPARENT
 from toga_cocoa.colors import native_color
 from toga_cocoa.constraints import Constraints
@@ -30,13 +32,12 @@ def container(self):
     @container.setter
     def container(self, container):
         if self.container:
-            if container:
-                raise RuntimeError("Already have a container")
-            else:
-                # existing container should be removed
-                self.constraints.container = None
-                self._container = None
-                self.native.removeFromSuperview()
+            assert container is None, "Widget already has a container"
+
+            # Existing container should be removed
+            self.constraints.container = None
+            self._container = None
+            self.native.removeFromSuperview()
         elif container:
             # setting container
             self._container = container
@@ -118,5 +119,6 @@ def add_constraints(self):
     def refresh(self):
         self.rehint()
 
+    @abstractmethod
     def rehint(self):
-        pass
+        ...

cocoa/src/toga_cocoa/widgets/optioncontainer.py

@@ -1,3 +1,5 @@
+from travertino.size import at_least
+
 from toga_cocoa.libs import NSObject, NSTabView, NSTabViewItem, objc_method
 from toga_cocoa.window import CocoaViewport
 
@@ -112,3 +114,7 @@ def get_current_tab_index(self):
 
     def set_current_tab_index(self, current_tab_index):
         self.native.selectTabViewItemAtIndex(current_tab_index)
+
+    def rehint(self):
+        self.interface.intrinsic.width = at_least(self.interface._MIN_WIDTH)
+        self.interface.intrinsic.height = at_least(self.interface._MIN_HEIGHT)

cocoa/src/toga_cocoa/widgets/splitcontainer.py

@@ -1,3 +1,5 @@
+from travertino.size import at_least
+
 from toga_cocoa.libs import NSObject, NSSize, NSSplitView, objc_method
 from toga_cocoa.window import CocoaViewport
 
@@ -79,3 +81,7 @@ def set_direction(self, value):
 
     def on_resize(self):
         pass
+
+    def rehint(self):
+        self.interface.intrinsic.width = at_least(self.interface._MIN_WIDTH)
+        self.interface.intrinsic.height = at_least(self.interface._MIN_HEIGHT)

cocoa/tests_backend/widgets/base.py

@@ -20,6 +20,11 @@ def assert_container(self, container):
         else:
             raise ValueError(f"cannot find {self.native} in {container_native}")
 
+    def assert_not_contained(self):
+        assert self.widget._impl.container is None
+        assert self.native.superview is None
+        assert self.native.window is None
+
     def assert_alignment(self, expected):
         assert self.alignment == expected
 
@@ -58,6 +63,16 @@ def width(self):
     def height(self):
         return self.native.frame.size.height
 
+    def assert_layout(self, size, position):
+        # Widget is contained and in a window.
+        assert self.widget._impl.container is not None
+        assert self.native.superview is not None
+        assert self.native.window is not None
+
+        # size and position is as expected.
+        assert (self.native.frame.size.width, self.native.frame.size.height) == size
+        assert (self.native.frame.origin.x, self.native.frame.origin.y) == position
+
     def assert_width(self, min_width, max_width):
         assert (
             min_width <= self.width <= max_width
@@ -80,3 +95,6 @@ def background_color(self):
 
     def press(self):
         self.native.performClick(None)
+
+    def has_focus(self):
+        return self.native.window.firstResponder == self.native

core/src/toga/widgets/activityindicator.py

@@ -26,6 +26,10 @@ def enabled(self, value):
         # ActivityIndicator doesn't have a "disabled" state
         pass
 
+    def focus(self):
+        "No-op; ActivityIndicator cannot accept input focus"
+        pass
+
     @property
     def is_running(self):
         """Determine if the activity indicator is currently running.

core/src/toga/widgets/base.py

@@ -247,5 +247,5 @@ def refresh_sublayouts(self):
             child.refresh_sublayouts()
 
     def focus(self):
-        """Give this widget to have the input focus."""
+        """Give this widget the input focus."""
         self._impl.focus()

core/src/toga/widgets/box.py

@@ -32,3 +32,7 @@ def __init__(
     def enabled(self, value):
         # Box doesn't have a "disabled" state
         pass
+
+    def focus(self):
+        "No-op; ActivityIndicator cannot accept input focus"
+        pass

core/src/toga/widgets/divider.py

@@ -32,6 +32,10 @@ def enabled(self, value):
         # Divider doesn't have a "disabled" state
         pass
 
+    def focus(self):
+        "No-op; Divider cannot accept input focus"
+        pass
+
     @property
     def direction(self):
         """The direction in which the visual separator will be drawn.

core/src/toga/widgets/label.py

@@ -24,6 +24,10 @@ def __init__(
 
         self.text = text
 
+    def focus(self):
+        "No-op; Label cannot accept input focus"
+        pass
+
     @property
     def text(self):
         """The text displayed by the label.

core/src/toga/widgets/optioncontainer.py

@@ -270,6 +270,9 @@ def _insert(self, index, text, widget, enabled=True):
 
 
 class OptionContainer(Widget):
+    _MIN_WIDTH = 100
+    _MIN_HEIGHT = 100
+
     """The option container widget.
 
     Args:

core/src/toga/widgets/splitcontainer.py

@@ -21,6 +21,9 @@ class SplitContainer(Widget):
             flex (boolean): Should the content expand when the widget is resized. (optional)
     """
 
+    _MIN_HEIGHT = 100
+    _MIN_WIDTH = 100
+
     HORIZONTAL = False
     VERTICAL = True
 

testbed/tests/widgets/properties.py

@@ -1,11 +1,13 @@
 from pytest import approx
 
+import toga
 from toga.colors import RED, TRANSPARENT, color as named_color
 from toga.fonts import BOLD, FANTASY, ITALIC, NORMAL, SERIF, SYSTEM
 from toga.style.pack import COLUMN
 
 from ..assertions import assert_color
 from ..data import COLORS, TEXTS
+from .probe import get_probe
 
 # An upper bound for widths
 MAX_WIDTH = 2000
@@ -47,6 +49,42 @@ async def test_enable_noop(widget, probe):
     assert probe.enabled
 
 
+# async def test_hidden(widget, probe):
+
+
+async def test_focus(widget, probe):
+    "The widget can be given focus"
+    # Add a separate widget that can take take focus
+    other = toga.Button("Other")
+    widget.parent.add(other)
+    other_probe = get_probe(other)
+
+    other.focus()
+    assert not probe.has_focus()
+    assert other_probe.has_focus()
+
+    widget.focus()
+    assert probe.has_focus()
+    assert not other_probe.has_focus()
+
+
+async def test_focus_noop(widget, probe):
+    "The widget cannot be given focus"
+    # Add a separate widget that can take take focus
+    other = toga.Button("Other")
+    widget.parent.add(other)
+    other_probe = get_probe(other)
+
+    other.focus()
+    assert not probe.has_focus()
+    assert other_probe.has_focus()
+
+    # Widget has *not* taken focus
+    widget.focus()
+    assert not probe.has_focus()
+    assert other_probe.has_focus()
+
+
 async def test_text(widget, probe):
     "The text displayed on a widget can be changed"
     for text in TEXTS:
@@ -197,7 +235,7 @@ async def test_flex_widget_size(widget, probe):
     # Check the initial widget size
     # Match isn't exact because of pixel scaling on some platforms
     assert probe.width == approx(100, rel=0.01)
-    assert probe.height == approx(100, rel=0.01)
+    assert probe.height == approx(200, rel=0.01)
 
     # Drop the fixed height, and make the widget flexible
     widget.style.flex = 1

testbed/tests/widgets/test_activityindicator.py

@@ -5,6 +5,7 @@
 from ..conftest import skip_on_platforms
 from .properties import (  # noqa: F401
     test_enable_noop,
+    test_focus_noop,
 )
 
 

testbed/tests/widgets/test_box.py

@@ -1,16 +1,67 @@
 import pytest
 
 import toga
+from toga.colors import BLACK, BLUE, GREEN, RED
 from toga.style import Pack
 
+from .probe import get_probe
 from .properties import (  # noqa: F401
     test_background_color,
     test_background_color_reset,
     test_enable_noop,
     test_flex_widget_size,
+    test_focus_noop,
 )
 
 
 @pytest.fixture
 async def widget():
-    return toga.Box(style=Pack(width=100, height=100))
+    return toga.Box(style=Pack(width=100, height=200))
+
+
+async def test_parenting(widget, probe):
+    widget.style.background_color = RED
+    box = widget.parent
+
+    child = toga.Box(style=Pack(width=50, height=75, background_color=GREEN))
+    child_probe = get_probe(child)
+    other = toga.Box(style=Pack(width=100, height=200, background_color=BLUE))
+    other_probe = get_probe(other)
+    other_child = toga.Box(style=Pack(width=25, height=50, background_color=BLACK))
+    other.add(other_child)
+
+    # Layout has the test widget, plus other, horizontally laid out.
+    # Child isn't in the layout yet.
+    box.add(other)
+    await probe.redraw()
+    probe.assert_layout(position=(0, 0), size=(100, 200))
+    other_probe.assert_layout(position=(100, 0), size=(100, 200))
+    child_probe.assert_not_contained()
+
+    # Add child to widget.
+    widget.add(child)
+    await probe.redraw()
+    probe.assert_layout(position=(0, 0), size=(100, 200))
+    other_probe.assert_layout(position=(100, 0), size=(100, 200))
+    child_probe.assert_layout(position=(0, 0), size=(50, 75))
+
+    # Reparent child to other without removing first
+    other.add(child)
+    await probe.redraw()
+    probe.assert_layout(position=(0, 0), size=(100, 200))
+    other_probe.assert_layout(position=(100, 0), size=(100, 200))
+    child_probe.assert_layout(position=(125, 0), size=(50, 75))
+
+    # Remove child from the layout entirely
+    other.remove(child)
+    await probe.redraw()
+    probe.assert_layout(position=(0, 0), size=(100, 200))
+    other_probe.assert_layout(position=(100, 0), size=(100, 200))
+    child_probe.assert_not_contained()
+
+    # Insert the child into the root layout
+    box.insert(1, child)
+    await probe.redraw()
+    probe.assert_layout(position=(0, 0), size=(100, 200))
+    other_probe.assert_layout(position=(150, 0), size=(100, 200))
+    child_probe.assert_layout(position=(100, 0), size=(50, 75))

testbed/tests/widgets/test_button.py

@@ -14,6 +14,7 @@
     test_color_reset,
     test_enabled,
     test_flex_horizontal_widget_size,
+    test_focus,
     test_font,
     test_font_attrs,
     test_text_width_change,

testbed/tests/widgets/test_divider.py

@@ -6,6 +6,7 @@
 from ..conftest import skip_on_platforms
 from .properties import (  # noqa: F401
     test_enable_noop,
+    test_focus_noop,
 )
 
 

testbed/tests/widgets/test_label.py

@@ -11,6 +11,7 @@
     test_color_reset,
     test_enabled,
     test_flex_horizontal_widget_size,
+    test_focus_noop,
     test_font,
     test_font_attrs,
     test_text,

testbed/tests/widgets/test_switch.py

@@ -10,6 +10,7 @@
     test_color_reset,
     test_enabled,
     test_flex_horizontal_widget_size,
+    test_focus,
     test_font,
     test_font_attrs,
     test_text_width_change,