from qgis.core import *
from qgis.gui import *

class TestLayer(QgsPluginLayer):

    LAYER_TYPE=u'TestLayer'

    def __init__(self):
        QgsPluginLayer.__init__(self, TestLayer.LAYER_TYPE)
        self.setValid(True)

    def draw(self, rendererContext):
        print("TestLayer::draw")
        return True

    def noise(self):
        print("TestLayer::noise")
        return True

class TestLayerType(QgsPluginLayerType):
    def __init__(self):
        QgsPluginLayerType.__init__(self, TestLayer.LAYER_TYPE)

    def createLayer(self):
        print("TestLayerType::createLayer")
        return TestLayer()


registry = QgsPluginLayerRegistry.instance()

print(registry.removePluginLayerType(TestLayer.LAYER_TYPE))

print(registry.addPluginLayerType(TestLayerType()))
print(registry.pluginLayerType(TestLayer.LAYER_TYPE))

# A TestLayer object should be created but instead a QgsPluginLayer appears
print(registry.createLayer(TestLayer.LAYER_TYPE))

# The wrong draw() function is called (from QgsPluginLayer)
print(registry.createLayer(TestLayer.LAYER_TYPE).draw(QgsRenderContext()))

# The function noise() of TestLayer is not found
print(registry.createLayer(TestLayer.LAYER_TYPE).noise())



""" Output in QGIS 2.8.1 and 2.11 Python console:

execfile(u'/home/soeren/Dokumente/.../PluginLayerTest.py'.encode('UTF-8'))
False
True
<__console__.TestLayerType object at 0x7febfe2db770>
TestLayerType::createLayer
<qgis._core.QgsPluginLayer object at 0x7febfe2db6d8>
TestLayerType::createLayer
False
TestLayerType::createLayer
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/home/soeren/Dokumente.../PluginLayerTest.py", line 36, in <module>
    print(registry.createLayer(TestLayer.LAYER_TYPE).noise())
AttributeError: 'QgsPluginLayer' object has no attribute 'noise'

"""