Handling nan values for assert_ functions.

1 files changed, 19 insertions, 2 deletions

diff --git a/numpy/testing/utils.py b/numpy/testing/utils.py
index 4f4c3496c..cd0ec9781 100644
--- a/numpy/testing/utils.py
+++ b/numpy/testing/utils.py
@@ -186,7 +186,7 @@ def assert_approx_equal(actual,desired,significant=7,err_msg='',verbose=True):
 
 def assert_array_compare(comparison, x, y, err_msg='', verbose=True,
                          header=''):
-    from numpy.core import asarray
+    from numpy.core import asarray, isnan
     x = asarray(x)
     y = asarray(y)
     try:
@@ -199,7 +199,24 @@ def assert_array_compare(comparison, x, y, err_msg='', verbose=True,
                                 verbose=verbose, header=header,
                                 names=('x', 'y'))
             assert cond, msg
-        val = comparison(x,y)
+        if isnan(x) or isnan(y):
+            # Handling nan: we first check that x and y have the nan at the
+            # same locations, and then we mask the nan and do the comparison as
+            # usual.
+            xnanid = isnan(x)
+            ynanid = isnan(y)
+            try:
+                assert_array_equal(xnanid, ynanid)
+            except AssertionError:
+                msg = build_err_msg([x, y],
+                                    err_msg
+                                    + '\n(x and y nan location mismatch %s, '
+                                    + '%s mismatch)' % (xnanid, ynanid),
+                                    verbose=verbose, header=header,
+                                    names=('x', 'y'))
+            val = comparison(x[~xnanid], y[~ynanid])
+        else:
+            val = comparison(x,y)
         if isinstance(val, bool):
             cond = val
             reduced = [0]