Added test for overlapping array assignments.

1 files changed, 80 insertions, 0 deletions

diff --git a/numpy/core/tests/test_multiarray_assignment.py b/numpy/core/tests/test_multiarray_assignment.py
new file mode 100644
index 000000000..43f586db1
--- /dev/null
+++ b/numpy/core/tests/test_multiarray_assignment.py
@@ -0,0 +1,80 @@
+import numpy as np
+from numpy.testing import TestCase
+
+ndims = 2
+size = 10
+shape = tuple([size] * ndims)
+
+
+def _indices_for_nelems(nelems):
+    """Returns slices of length nelems, from start onwards, in direction sign."""
+
+    if nelems == 0:
+        return [size // 2]  # int index
+
+    res = []
+    for step in (1, 2):
+        for sign in (-1, 1):
+            start = size // 2 - nelems * step * sign // 2
+            stop = start + nelems * step * sign
+            res.append(slice(start, stop, step * sign))
+
+    return res
+
+
+def _indices_for_axis():
+    """Returns (src, dst) pairs of indices."""
+
+    res = []
+    for nelems in (0, 2, 3):
+        ind = _indices_for_nelems(nelems)
+
+        # no itertools.product available in Py2.4
+        res.extend([(a, b) for a in ind for b in ind])  # all assignments of size "nelems"
+
+    return res
+
+
+def _indices(ndims):
+    """Returns ((axis0_src, axis0_dst), (axis1_src, axis1_dst), ... ) index pairs."""
+
+    ind = _indices_for_axis()
+
+    # no itertools.product available in Py2.4
+
+    res = [[]]
+    for i in xrange(ndims):
+        newres = []
+        for elem in ind:
+            for others in res:
+                newres.append([elem] + others)
+        res = newres
+
+    return res
+
+
+def _check_assignment(srcidx, dstidx):
+    """Check assignment arr[dstidx] = arr[srcidx] works."""
+
+    arr = np.arange(np.product(shape)).reshape(shape)
+
+    cpy = arr.copy()
+
+    cpy[dstidx] = arr[srcidx]
+    arr[dstidx] = arr[srcidx]
+
+    assert np.all(arr == cpy), 'assigning arr[%s] = arr[%s]' % (dstidx, srcidx)
+
+
+# nose doesn't expect methods to be generators but functions can be,
+# so we use a function not a Test class here.
+def test_overlapping_assignments():
+    """Test automatically generated assignments which overlap in memory."""
+
+    inds = _indices(ndims)
+
+    for ind in inds:
+        srcidx = tuple([a[0] for a in ind])
+        dstidx = tuple([a[1] for a in ind])
+
+        yield _check_assignment, srcidx, dstidx