Correct iOS test failure caused by focus.

iOS/src/toga_iOS/widgets/base.py

@@ -65,8 +65,13 @@ def get_enabled(self):
     def set_enabled(self, value):
         self.native.setEnabled(value)
 
+    @property
+    def has_focus(self):
+        return self.native.isFirstResponder
+
     def focus(self):
-        self.native.becomeFirstResponder()
+        if not self.has_focus:
+            self.native.becomeFirstResponder()
 
     def get_tab_index(self):
         self.interface.factory.not_implemented("Widget.get_tab_index()")

iOS/src/toga_iOS/widgets/multilinetextinput.py

@@ -137,7 +137,7 @@ def get_value(self):
 
     def set_value(self, value):
         self.native.text = value
-        self.placeholder_label.setHidden(len(self.native.text) > 0)
+        self.placeholder_label.setHidden(self.has_focus or len(self.native.text) > 0)
         self.interface.on_change(None)
 
     def set_color(self, value):

testbed/tests/widgets/properties.py

@@ -147,9 +147,8 @@ async def test_placeholder(widget, probe):
 
 async def test_placeholder_focus(widget, probe):
     "Placeholders interact correctly with focus changes"
-
     widget.value = ""
-    widget.placeholder = "replacement"
+    widget.placeholder = "placeholder"
     hides_on_focus = probe.placeholder_hides_on_focus
 
     # Placeholder visibility can be focus dependent, so add another
@@ -162,58 +161,73 @@ async def test_placeholder_focus(widget, probe):
     widget.focus()
     await probe.redraw("Widget has focus")
     assert widget.value == ""
-    assert widget.placeholder == "replacement"
-    assert probe.value == "" if hides_on_focus else "replacement"
+    assert widget.placeholder == "placeholder"
+    assert probe.value == "" if hides_on_focus else "placeholder"
     assert probe.placeholder_visible == (not hides_on_focus)
 
     # Give a different widget focus; this will show the placeholder
     other.focus()
     await probe.redraw("Widget has lost focus")
     assert widget.value == ""
-    assert widget.placeholder == "replacement"
-    assert probe.value == "replacement"
+    assert widget.placeholder == "placeholder"
+    assert probe.value == "placeholder"
     assert probe.placeholder_visible
 
     # Give the widget focus, again
     widget.focus()
     await probe.redraw("Widget has focus; placeholder may not be visible")
     assert widget.value == ""
-    assert widget.placeholder == "replacement"
-    assert probe.value == "" if hides_on_focus else "replacement"
+    assert widget.placeholder == "placeholder"
+    assert probe.value == "" if hides_on_focus else "placeholder"
     assert probe.placeholder_visible == (not hides_on_focus)
 
     # Change the placeholder text while the widget has focus
-    widget.placeholder = "placeholder"
-    await probe.redraw("Widget placeholder should be 'placeholder'")
+    widget.placeholder = "replacement"
+    await probe.redraw("Widget placeholder should be 'replacement'")
     assert widget.value == ""
-    assert widget.placeholder == "placeholder"
-    assert probe.value == "" if hides_on_focus else "placeholder"
+    assert widget.placeholder == "replacement"
+    assert probe.value == "" if hides_on_focus else "replacement"
     assert probe.placeholder_visible == (not hides_on_focus)
 
     # Give a different widget focus; this will show the placeholder
     other.focus()
     await probe.redraw("Widget has lost focus; placeholder should be visible")
     assert widget.value == ""
-    assert widget.placeholder == "placeholder"
-    assert probe.value == "placeholder"
+    assert widget.placeholder == "replacement"
+    assert probe.value == "replacement"
     assert probe.placeholder_visible
 
     # Focus in and out while a value is set.
     widget.value = "example"
     widget.focus()
     await probe.redraw("Widget has focus; value is set")
     assert widget.value == "example"
-    assert widget.placeholder == "placeholder"
+    assert widget.placeholder == "replacement"
     assert probe.value == "example"
     assert not probe.placeholder_visible
 
     other.focus()
     await probe.redraw("Widget has lost focus, value is set")
     assert widget.value == "example"
-    assert widget.placeholder == "placeholder"
+    assert widget.placeholder == "replacement"
     assert probe.value == "example"
     assert not probe.placeholder_visible
 
+    # Value cleared while focus is set
+    widget.focus()
+    await probe.redraw("Widget has focus; value is set")
+    assert widget.value == "example"
+    assert widget.placeholder == "replacement"
+    assert probe.value == "example"
+    assert not probe.placeholder_visible
+
+    widget.value = ""
+    await probe.redraw("Value has been cleared")
+    assert widget.value == ""
+    assert widget.placeholder == "replacement"
+    assert probe.value == "" if hides_on_focus else "replacement"
+    assert probe.placeholder_visible == (not hides_on_focus)
+
 
 async def test_placeholder_color(widget, probe):
     "Placeholders interact correctly with custom colors"

testbed/tests/widgets/test_multilinetextinput.py

@@ -111,6 +111,7 @@ async def test_on_change_handler(widget, probe):
     # Install a handler, and give the widget focus.
     handler = Mock()
     widget.on_change = handler
+    widget.placeholder = "placeholder"
     widget.focus()
 
     # Programmatic value changes trigger the event handler