def testThemes(self):
layout = QgsPrintLayout(QgsProject.instance())
layout.setName('LAYOUT')
map = QgsLayoutItemMap(layout)
layout.addLayoutItem(map)
legend = QgsLayoutItemLegend(layout)
self.assertFalse(legend.themeName())
legend.setLinkedMap(map)
self.assertFalse(legend.themeName())
map.setFollowVisibilityPresetName('theme1')
map.setFollowVisibilityPreset(True)
self.assertEqual(legend.themeName(), 'theme1')
map.setFollowVisibilityPresetName('theme2')
self.assertEqual(legend.themeName(), 'theme2')
map.setFollowVisibilityPreset(False)
self.assertFalse(legend.themeName())
# with theme set before linking map
map2 = QgsLayoutItemMap(layout)
map2.setFollowVisibilityPresetName('theme3')
map2.setFollowVisibilityPreset(True)
legend.setLinkedMap(map2)
self.assertEqual(legend.themeName(), 'theme3')
map2.setFollowVisibilityPresetName('theme2')
self.assertEqual(legend.themeName(), 'theme2')
# replace with map with no theme
map3 = QgsLayoutItemMap(layout)
legend.setLinkedMap(map3)
self.assertFalse(legend.themeName())
