extension UITraitEnvironment {
    func stubTraitCollection(traitCollection: UITraitCollection) {
        let partialMock = OCMockObject.partialMockForObject(self)
        let traitCollection = UITraitCollection()
        partialMock.stub().andReturn(traitCollection).traitCollection()
        self.traitCollectionDidChange(nil)
    }


    func stubHorizontalSizeClass(horizontalSizeClass: UIUserInterfaceSizeClass) {
        self.stubTraitCollection(UITraitCollection(horizontalSizeClass: horizontalSizeClass))
    }

    func stubVerticalSizeClass(verticalSizeClass: UIUserInterfaceSizeClass) {
        self.stubTraitCollection(UITraitCollection(verticalSizeClass: verticalSizeClass))

    }

    func stubHorizontalSizeClass(horizontalSizeClass: UIUserInterfaceSizeClass, verticalSizeClass: UIUserInterfaceSizeClass) {
        self.stubTraitCollection(UITraitCollection(traitsFromCollections: [
            UITraitCollection(horizontalSizeClass: horizontalSizeClass),
            UITraitCollection(verticalSizeClass: verticalSizeClass),
        ]))
    }
}