Add tests for 'regular_grid()'

skimage/util/tests/test_regular_grid.py

@@ -0,0 +1,33 @@
+import numpy as np
+from nose.tools import raises
+from numpy.testing import assert_equal
+from skimage.util.regular_grid import regular_grid
+
+
+def test_regular_grid_2d_8():
+    ar = np.zeros((20, 40))
+    g = regular_grid(ar.shape, 8)
+    assert_equal(g, [slice(5.0, None, 10.0), slice(5.0, None, 10.0)])
+    ar[g] = 1
+    assert_equal(ar.sum(), 8)
+
+
+def test_regular_grid_2d_32():
+    ar = np.zeros((20, 40))
+    g = regular_grid(ar.shape, 32)
+    assert_equal(g, [slice(2.0, None, 5.0), slice(2.0, None, 5.0)])
+    ar[g] = 1
+    assert_equal(ar.sum(), 32)
+
+
+def test_regular_grid_3d_8():
+    ar = np.zeros((3, 20, 40))
+    g = regular_grid(ar.shape, 8)
+    assert_equal(g, [slice(1.0, None, 3.0), slice(5.0, None, 10.0),
+                     slice(5.0, None, 10.0)])
+    ar[g] = 1
+    assert_equal(ar.sum(), 8)
+
+
+if __name__ == '__main__':
+    np.testing.run_module_suite()