Added test cases for slicing

pystencils_tests/test_slicing.py

+import numpy as np
+from pystencils import create_data_handling
+from pystencils.slicing import SlicedGetter, make_slice, SlicedGetterDataHandling, shift_slice, slice_intersection
+
+
+def test_sliced_getter():
+    def get_slice(slice_obj=None):
+        arr = np.ones((10, 10))
+        if slice_obj is None:
+            slice_obj = make_slice[:, :]
+
+        return arr[slice_obj]
+
+    sli = SlicedGetter(get_slice)
+
+    test = make_slice[2:-2, 2:-2]
+    assert sli[test].shape == (6, 6)
+
+
+def test_sliced_getter_data_handling():
+    domain_shape = (10, 10)
+
+    dh = create_data_handling(domain_size=domain_shape, default_ghost_layers=1)
+    dh.add_array("src", values_per_cell=1)
+    dh.fill("src", 1.0, ghost_layers=True)
+
+    dh.add_array("dst", values_per_cell=1)
+    dh.fill("dst", 0.0, ghost_layers=True)
+
+    sli = SlicedGetterDataHandling(dh, 'dst')
+    slice_obj = make_slice[2:-2, 2:-2]
+    assert np.sum(sli[slice_obj]) == 0
+
+    sli = SlicedGetterDataHandling(dh, 'src')
+    slice_obj = make_slice[2:-2, 2:-2]
+    assert np.sum(sli[slice_obj]) == 36
+
+
+def test_shift_slice():
+
+    sh = shift_slice(make_slice[2:-2, 2:-2], [1, 2])
+    assert sh[0] == slice(3, -1, None)
+    assert sh[1] == slice(4, 0, None)
+
+    sh = shift_slice(make_slice[2:-2, 2:-2], 1)
+    assert sh[0] == slice(3, -1, None)
+    assert sh[1] == slice(3, -1, None)
+
+    sh = shift_slice([2, 4], 1)
+    assert sh[0] == 3
+    assert sh[1] == 5
+
+    sh = shift_slice([2, None], 1)
+    assert sh[0] == 3
+    assert sh[1] is None
+
+    sh = shift_slice([1.5, 1.5], 1)
+    assert sh[0] == 1.5
+    assert sh[1] == 1.5
+
+
+def test_slice_intersection():
+    sl1 = make_slice[1:10, 1:10]
+    sl2 = make_slice[5:15, 5:15]
+
+    intersection = slice_intersection(sl1, sl2)
+    assert intersection[0] == slice(5, 10, None)
+    assert intersection[1] == slice(5, 10, None)
+
+    sl2 = make_slice[12:15, 12:15]
+
+    intersection = slice_intersection(sl1, sl2)
+    assert intersection is None