Allow view_as_window to take a tuple step, and update tests

skimage/util/tests/test_shape.py

@@ -47,7 +47,7 @@ def test_view_as_blocks_2D_array():
     A = np.arange(4 * 4).reshape(4, 4)
     B = view_as_blocks(A, (2, 2))
     assert_equal(B[0, 1], np.array([[2, 3],
-                                   [6, 7]]))
+                                    [6, 7]]))
     assert_equal(B[1, 0, 1, 1], 13)
 
 
@@ -67,12 +67,6 @@ def test_view_as_windows_input_not_array():
     view_as_windows(A, (2,))
 
 
-@raises(TypeError)
-def test_view_as_windows_window_not_tuple():
-    A = np.arange(10)
-    view_as_windows(A, [2])
-
-
 @raises(ValueError)
 def test_view_as_windows_wrong_window_dimension():
     A = np.arange(10)
@@ -96,6 +90,7 @@ def test_view_as_windows_step_below_one():
     A = np.arange(10)
     view_as_windows(A, (11,), step=0.9)
 
+
 def test_view_as_windows_1D():
     A = np.arange(10)
     window_shape = (3,)
@@ -135,7 +130,7 @@ def test_view_as_windows_2D():
 
 def test_view_as_windows_with_skip():
     A = np.arange(20).reshape((5, 4))
-    B = view_as_windows(A, (2, 2), step=2)
+    B = view_as_windows(A, 2, step=2)
     assert_equal(B, [[[[0, 1],
                        [4, 5]],
                       [[2, 3],
@@ -145,7 +140,7 @@ def test_view_as_windows_with_skip():
                       [[10, 11],
                        [14, 15]]]])
 
-    C = view_as_windows(A, (2, 2), step=4)
+    C = view_as_windows(A, 2, step=4)
     assert_equal(C.shape, (1, 1, 2, 2))
 
 
@@ -157,5 +152,29 @@ def test_views_non_contiguous():
     assert_warns(RuntimeWarning, view_as_windows, A, (2, 2))
 
 
+def test_view_as_windows_step_tuple():
+    A = np.arange(24).reshape((6, 4))
+    B = view_as_windows(A, (3, 2), step=3)
+    assert B.shape == (2, 1, 3, 2)
+    assert B.size != A.size
+
+    C = view_as_windows(A, (3, 2), step=(3, 2))
+    assert C.shape == (2, 2, 3, 2)
+    assert C.size == A.size
+
+    assert_equal(C, [[[[0,  1],
+                       [4,  5],
+                       [8,  9]],
+                      [[2,  3],
+                       [6,  7],
+                       [10, 11]]],
+                     [[[12, 13],
+                         [16, 17],
+                         [20, 21]],
+                      [[14, 15],
+                         [18, 19],
+                         [22, 23]]]])
+
+
 if __name__ == '__main__':
     np.testing.run_module_suite()