BUG: Fix improper usage of warning filters in the tests

7 files changed, 88 insertions, 52 deletions

diff --git a/numpy/core/tests/test_maskna.py b/numpy/core/tests/test_maskna.py
index 958dc8900..341ed0bc2 100644
--- a/numpy/core/tests/test_maskna.py
+++ b/numpy/core/tests/test_maskna.py
@@ -2,7 +2,7 @@ import numpy as np
 from numpy.compat import asbytes
 from numpy.testing import *
 import sys, warnings
-
+from numpy.testing.utils import WarningManager
 
 def test_array_maskna_flags():
     a = np.arange(3)
@@ -200,6 +200,8 @@ def test_array_maskna_astype():
     dtdst.append(np.dtype('datetime64[D]'))
     dtdst.append(np.dtype('timedelta64[s]'))
 
+    warn_ctx = WarningManager()
+    warn_ctx.__enter__()
     try:
         warnings.simplefilter("ignore", np.ComplexWarning)
         for dt1 in dtsrc:
@@ -212,7 +214,7 @@ def test_array_maskna_astype():
                 assert_(b.flags.ownmaskna, msg)
                 assert_(np.isna(b[1]), msg)
     finally:
-        warnings.simplefilter("default", np.ComplexWarning)
+        warn_ctx.__exit__()
 
 
 def test_array_maskna_repr():
diff --git a/numpy/core/tests/test_memmap.py b/numpy/core/tests/test_memmap.py
index fa4eb9de0..ed07532d7 100644
--- a/numpy/core/tests/test_memmap.py
+++ b/numpy/core/tests/test_memmap.py
@@ -1,6 +1,5 @@
 from tempfile import NamedTemporaryFile, mktemp
 import os
-import warnings
 
 from numpy import memmap
 from numpy import arange, allclose
diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py
index adcd73872..6641a99f0 100644
--- a/numpy/core/tests/test_multiarray.py
+++ b/numpy/core/tests/test_multiarray.py
@@ -7,6 +7,9 @@ from nose import SkipTest
 from numpy.core import *
 from numpy.core.multiarray_tests import test_neighborhood_iterator, test_neighborhood_iterator_oob
 
+import warnings
+from numpy.testing.utils import WarningManager
+
 # Need to test an object that does not fully implement math interface
 from datetime import timedelta
 
@@ -1996,15 +1999,17 @@ class TestStackedNeighborhoodIter(TestCase):
 
 class TestWarnings(object):
     def test_complex_warning(self):
-        import warnings
-
         x = np.array([1,2])
         y = np.array([1-2j,1+2j])
 
-        warnings.simplefilter("error", np.ComplexWarning)
-        assert_raises(np.ComplexWarning, x.__setitem__, slice(None), y)
-        assert_equal(x, [1,2])
-        warnings.simplefilter("default", np.ComplexWarning)
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            warnings.simplefilter("error", np.ComplexWarning)
+            assert_raises(np.ComplexWarning, x.__setitem__, slice(None), y)
+            assert_equal(x, [1,2])
+        finally:
+            warn_ctx.__exit__()
 
 if sys.version_info >= (2, 6):
 
diff --git a/numpy/core/tests/test_regression.py b/numpy/core/tests/test_regression.py
index 5440949a1..55d5b6ec6 100644
--- a/numpy/core/tests/test_regression.py
+++ b/numpy/core/tests/test_regression.py
@@ -1406,11 +1406,13 @@ class TestRegression(TestCase):
         for tp in [np.csingle, np.cdouble, np.clongdouble]:
             x = tp(1+2j)
             assert_warns(np.ComplexWarning, float, x)
-            ctx = WarningManager()
-            ctx.__enter__()
-            warnings.simplefilter('ignore')
-            assert_equal(float(x), float(x.real))
-            ctx.__exit__()
+            warn_ctx = WarningManager()
+            warn_ctx.__enter__()
+            try:
+                warnings.simplefilter('ignore')
+                assert_equal(float(x), float(x.real))
+            finally:
+                warn_ctx.__exit__()
 
     def test_complex_scalar_complex_cast(self):
         for tp in [np.csingle, np.cdouble, np.clongdouble]:
diff --git a/numpy/lib/tests/test_io.py b/numpy/lib/tests/test_io.py
index 356534a25..04ca3fb4e 100644
--- a/numpy/lib/tests/test_io.py
+++ b/numpy/lib/tests/test_io.py
@@ -6,6 +6,7 @@ from tempfile import mkstemp, NamedTemporaryFile
 import time
 from datetime import datetime
 import warnings
+from numpy.testing.utils import WarningManager
 
 import numpy as np
 import numpy.ma as ma
@@ -460,13 +461,19 @@ class TestLoadTxt(TestCase):
         assert_array_equal(x, a)
 
     def test_empty_file(self):
-        warnings.filterwarnings("ignore", message="loadtxt: Empty input file:")
-        c = StringIO()
-        x = np.loadtxt(c)
-        assert_equal(x.shape, (0,))
-        x = np.loadtxt(c, dtype=np.int64)
-        assert_equal(x.shape, (0,))
-        assert_(x.dtype == np.int64)
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            warnings.filterwarnings("ignore",
+                    message="loadtxt: Empty input file:")
+            c = StringIO()
+            x = np.loadtxt(c)
+            assert_equal(x.shape, (0,))
+            x = np.loadtxt(c, dtype=np.int64)
+            assert_equal(x.shape, (0,))
+            assert_(x.dtype == np.int64)
+        finally:
+            warn_ctx.__exit__()
 
 
     def test_unused_converter(self):
@@ -707,25 +714,29 @@ class TestFromTxt(TestCase):
         assert_equal(test, ctrl)
 
     def test_skip_footer_with_invalid(self):
-        basestr = '1 1\n2 2\n3 3\n4 4\n5  \n6  \n7  \n'
-        warnings.filterwarnings("ignore")
-        # Footer too small to get rid of all invalid values
-        assert_raises(ValueError, np.genfromtxt,
-                      StringIO(basestr), skip_footer=1)
-#        except ValueError:
-#            pass
-        a = np.genfromtxt(StringIO(basestr), skip_footer=1, invalid_raise=False)
-        assert_equal(a, np.array([[1., 1.], [2., 2.], [3., 3.], [4., 4.]]))
-        #
-        a = np.genfromtxt(StringIO(basestr), skip_footer=3)
-        assert_equal(a, np.array([[1., 1.], [2., 2.], [3., 3.], [4., 4.]]))
-        #
-        basestr = '1 1\n2  \n3 3\n4 4\n5  \n6 6\n7 7\n'
-        a = np.genfromtxt(StringIO(basestr), skip_footer=1, invalid_raise=False)
-        assert_equal(a, np.array([[1., 1.], [3., 3.], [4., 4.], [6., 6.]]))
-        a = np.genfromtxt(StringIO(basestr), skip_footer=3, invalid_raise=False)
-        assert_equal(a, np.array([[1., 1.], [3., 3.], [4., 4.]]))
-        warnings.resetwarnings()
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            basestr = '1 1\n2 2\n3 3\n4 4\n5  \n6  \n7  \n'
+            warnings.filterwarnings("ignore")
+            # Footer too small to get rid of all invalid values
+            assert_raises(ValueError, np.genfromtxt,
+                          StringIO(basestr), skip_footer=1)
+    #        except ValueError:
+    #            pass
+            a = np.genfromtxt(StringIO(basestr), skip_footer=1, invalid_raise=False)
+            assert_equal(a, np.array([[1., 1.], [2., 2.], [3., 3.], [4., 4.]]))
+            #
+            a = np.genfromtxt(StringIO(basestr), skip_footer=3)
+            assert_equal(a, np.array([[1., 1.], [2., 2.], [3., 3.], [4., 4.]]))
+            #
+            basestr = '1 1\n2  \n3 3\n4 4\n5  \n6 6\n7 7\n'
+            a = np.genfromtxt(StringIO(basestr), skip_footer=1, invalid_raise=False)
+            assert_equal(a, np.array([[1., 1.], [3., 3.], [4., 4.], [6., 6.]]))
+            a = np.genfromtxt(StringIO(basestr), skip_footer=3, invalid_raise=False)
+            assert_equal(a, np.array([[1., 1.], [3., 3.], [4., 4.]]))
+        finally:
+            warn_ctx.__exit__()
 
 
     def test_header(self):
@@ -1030,10 +1041,15 @@ M   33  21.99
 
     def test_empty_file(self):
         "Test that an empty file raises the proper warning."
-        warnings.filterwarnings("ignore", message="genfromtxt: Empty input file:")
-        data = StringIO()
-        test = np.genfromtxt(data)
-        assert_equal(test, np.array([]))
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            warnings.filterwarnings("ignore", message="genfromtxt: Empty input file:")
+            data = StringIO()
+            test = np.genfromtxt(data)
+            assert_equal(test, np.array([]))
+        finally:
+            warn_ctx.__exit__()
 
     def test_fancy_dtype_alt(self):
         "Check that a nested dtype isn't MIA"
diff --git a/numpy/ma/tests/test_core.py b/numpy/ma/tests/test_core.py
index 95219beb1..f4ec54dc4 100644
--- a/numpy/ma/tests/test_core.py
+++ b/numpy/ma/tests/test_core.py
@@ -18,6 +18,7 @@ import numpy.ma.core
 from numpy.ma.core import *
 
 from numpy.compat import asbytes, asbytes_nested
+from numpy.testing.utils import WarningManager
 
 pi = np.pi
 
@@ -426,9 +427,13 @@ class TestMaskedArray(TestCase):
         assert_equal(1.0, float(array([[1]])))
         self.assertRaises(TypeError, float, array([1, 1]))
         #
-        warnings.simplefilter('ignore', UserWarning)
-        assert_(np.isnan(float(array([1], mask=[1]))))
-        warnings.simplefilter('default', UserWarning)
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            warnings.simplefilter('ignore', UserWarning)
+            assert_(np.isnan(float(array([1], mask=[1]))))
+        finally:
+            warn_ctx.__exit__()
         #
         a = array([1, 2, 3], mask=[1, 0, 0])
         self.assertRaises(TypeError, lambda:float(a))
diff --git a/numpy/ma/tests/test_mrecords.py b/numpy/ma/tests/test_mrecords.py
index a6ee33b72..1e14042b0 100644
--- a/numpy/ma/tests/test_mrecords.py
+++ b/numpy/ma/tests/test_mrecords.py
@@ -22,6 +22,9 @@ from numpy.ma.testutils import *
 import numpy.ma as ma
 from numpy.ma import masked, nomask
 
+import warnings
+from numpy.testing.utils import WarningManager
+
 from numpy.ma.mrecords import MaskedRecords, mrecarray, fromarrays, \
                               fromtextfile, fromrecords, addfield
 
@@ -136,11 +139,15 @@ class TestMRecords(TestCase):
         rdata = data.view(MaskedRecords)
         val = ma.array([10,20,30], mask=[1,0,0])
         #
-        import warnings
-        warnings.simplefilter("ignore")
-        rdata['num'] = val
-        assert_equal(rdata.num, val)
-        assert_equal(rdata.num.mask, [1,0,0])
+        warn_ctx = WarningManager()
+        warn_ctx.__enter__()
+        try:
+            warnings.simplefilter("ignore")
+            rdata['num'] = val
+            assert_equal(rdata.num, val)
+            assert_equal(rdata.num.mask, [1,0,0])
+        finally:
+            warn_ctx.__exit__()
 
     def test_set_fields_mask(self):
         "Tests setting the mask of a field."