def test_widget_layout(web_fixture):
"""A Layout is used to add children to the Widget in customised ways, and to customise the Widget itself upon construction."""
class MyLayout(Layout):
def customise_widget(self):
self.widget.append_class('class-added-by-custom-layout')
def add_wrapped(self, child):
wrapper = self.widget.add_child(Div(self.view))
wrapper.add_child(child)
return child
fixture = web_fixture
widget_with_layout = Div(fixture.view)
assert not widget_with_layout.has_attribute('class')
assert not widget_with_layout.children
widget_with_layout.use_layout(MyLayout())
assert widget_with_layout.get_attribute(
'class') == 'class-added-by-custom-layout'
assert not widget_with_layout.children
widget_to_add = P(fixture.view)
widget_with_layout.layout.add_wrapped(widget_to_add)
[wrapper] = widget_with_layout.children
assert wrapper.children == [widget_to_add]
def widget_layout_errors(fixture):
"""A Layout can only be used with a single Widget, and a Widget can only have a single Layout."""
widget_with_layout = Div(fixture.view).use_layout(Layout())
with expected(ProgrammerError):
widget_with_layout.use_layout(Layout())
re_used_layout = Layout()
widget_with_reused_layout = Div(fixture.view).use_layout(re_used_layout)
with expected(ProgrammerError):
Div(fixture.view).use_layout(re_used_layout)
def column_layout_basics(fixture):
"""A ColumnLayout turns its Widget into a sequence of columns, each of which is a Div."""
layout = ColumnLayout('column_a', 'column_b')
widget = Div(fixture.view)
vassert(not widget.children)
widget.use_layout(layout)
column_a, column_b = widget.children
vassert(isinstance(column_a, Div))
vassert(isinstance(column_b, Div))
