Add tests for pyramid functions

skimage/transform/tests/test_pyramids.py

@@ -0,0 +1,41 @@
+from numpy.testing import assert_array_equal, run_module_suite
+from skimage import data
+from skimage.transform import (pyramid_reduce, pyramid_expand,
+                               build_gaussian_pyramid, build_laplacian_pyramid)
+
+
+image = data.lena()
+
+
+def test_pyramid_reduce():
+    rows, cols, dim = image.shape
+    out = pyramid_reduce(image, factor=2)
+    assert_array_equal(out.shape, (rows / 2, cols / 2, dim))
+
+
+def test_pyramid_expand():
+    rows, cols, dim = image.shape
+    out = pyramid_expand(image, factor=2)
+    assert_array_equal(out.shape, (rows * 2, cols * 2, dim))
+
+
+def test_build_gaussian_pyramid():
+    rows, cols, dim = image.shape
+    pyramid = build_gaussian_pyramid(image, factor=2)
+
+    for layer, out in enumerate(pyramid):
+        layer_shape = (rows / 2 ** layer, cols / 2 ** layer, dim)
+        assert_array_equal(out.shape, layer_shape)
+
+
+def test_build_laplacian_pyramid():
+    rows, cols, dim = image.shape
+    pyramid = build_laplacian_pyramid(image, factor=2)
+
+    for layer, out in enumerate(pyramid):
+        layer_shape = (rows / 2 ** layer, cols / 2 ** layer, dim)
+        assert_array_equal(out.shape, layer_shape)
+
+
+if __name__ == "__main__":
+    run_module_suite()