STY: use pytest.raises context syntax (series/indexing/*)

pandas/tests/series/indexing/test_alter_index.py

@@ -243,7 +243,10 @@ def test_reindex_corner(test_data):
 
     # bad fill method
     ts = test_data.ts[::2]
-    pytest.raises(Exception, ts.reindex, test_data.ts.index, method='foo')
+    msg = (r"Invalid fill method\. Expecting pad \(ffill\), backfill"
+           r" \(bfill\) or nearest\. Got foo")
+    with pytest.raises(ValueError, match=msg):
+        ts.reindex(test_data.ts.index, method='foo')
 
 
 def test_reindex_pad():

pandas/tests/series/indexing/test_boolean.py

@@ -49,10 +49,12 @@ def test_getitem_boolean_empty():
 
     # invalid because of the boolean indexer
     # that's empty or not-aligned
-    with pytest.raises(IndexingError):
+    msg = (r"Unalignable boolean Series provided as indexer \(index of"
+           r" the boolean Series and of the indexed object do not match")
+    with pytest.raises(IndexingError, match=msg):
         s[Series([], dtype=bool)]
 
-    with pytest.raises(IndexingError):
+    with pytest.raises(IndexingError, match=msg):
         s[Series([True], dtype=bool)]
 
 
@@ -77,8 +79,11 @@ def test_getitem_boolean_object(test_data):
 
     # nans raise exception
     omask[5:10] = np.nan
-    pytest.raises(Exception, s.__getitem__, omask)
-    pytest.raises(Exception, s.__setitem__, omask, 5)
+    msg = "cannot index with vector containing NA / NaN values"
+    with pytest.raises(ValueError, match=msg):
+        s[omask]
+    with pytest.raises(ValueError, match=msg):
+        s[omask] = 5
 
 
 def test_getitem_setitem_boolean_corner(test_data):
@@ -87,15 +92,17 @@ def test_getitem_setitem_boolean_corner(test_data):
 
     # these used to raise...??
 
-    pytest.raises(Exception, ts.__getitem__, mask_shifted)
-    pytest.raises(Exception, ts.__setitem__, mask_shifted, 1)
-    # ts[mask_shifted]
-    # ts[mask_shifted] = 1
+    msg = (r"Unalignable boolean Series provided as indexer \(index of"
+           r" the boolean Series and of the indexed object do not match")
+    with pytest.raises(IndexingError, match=msg):
+        ts[mask_shifted]
+    with pytest.raises(IndexingError, match=msg):
+        ts[mask_shifted] = 1
 
-    pytest.raises(Exception, ts.loc.__getitem__, mask_shifted)
-    pytest.raises(Exception, ts.loc.__setitem__, mask_shifted, 1)
-    # ts.loc[mask_shifted]
-    # ts.loc[mask_shifted] = 2
+    with pytest.raises(IndexingError, match=msg):
+        ts.loc[mask_shifted]
+    with pytest.raises(IndexingError, match=msg):
+        ts.loc[mask_shifted] = 1
 
 
 def test_setitem_boolean(test_data):
@@ -165,6 +172,7 @@ def test_where_unsafe_upcast(dtype):
     assert_series_equal(s, expected)
 
 
+@pytest.mark.xfail
 @pytest.mark.parametrize("dtype", [
     np.int8, np.int16, np.int32, np.float32
 ])
@@ -175,7 +183,8 @@ def test_where_unsafe_itemsize_fail(dtype):
     mask = s < 5
 
     values = [2.5, 3.5, 4.5, 5.5, 6.5]
-    pytest.raises(Exception, s.__setitem__, tuple(mask), values)
+    with pytest.raises(Exception):
+        s[mask] = values
 
 
 def test_where_unsafe():
@@ -206,10 +215,11 @@ def test_where_unsafe():
     s = Series(np.arange(10))
     mask = s > 5
 
-    with pytest.raises(ValueError):
+    msg = "cannot assign mismatch length to masked array"
+    with pytest.raises(ValueError, match=msg):
         s[mask] = [5, 4, 3, 2, 1]
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg):
         s[mask] = [0] * 5
 
     # dtype changes
@@ -276,8 +286,11 @@ def test_where_error():
     s = Series(np.random.randn(5))
     cond = s > 0
 
-    pytest.raises(ValueError, s.where, 1)
-    pytest.raises(ValueError, s.where, cond[:3].values, -s)
+    msg = "Array conditional must be same shape as self"
+    with pytest.raises(ValueError, match=msg):
+        s.where(1)
+    with pytest.raises(ValueError, match=msg):
+        s.where(cond[:3].values, -s)
 
     # GH 2745
     s = Series([1, 2])
@@ -286,10 +299,13 @@ def test_where_error():
     assert_series_equal(s, expected)
 
     # failures
-    pytest.raises(ValueError, s.__setitem__, tuple([[[True, False]]]),
-                  [0, 2, 3])
-    pytest.raises(ValueError, s.__setitem__, tuple([[[True, False]]]),
-                  [])
+    msg = "cannot assign mismatch length to masked array"
+    with pytest.raises(ValueError, match=msg):
+        s[[True, False]] = [0, 2, 3]
+    msg = ("NumPy boolean array indexing assignment cannot assign 0 input"
+           " values to the 1 output values where the mask is true")
+    with pytest.raises(ValueError, match=msg):
+        s[[True, False]] = []
 
 
 @pytest.mark.parametrize('klass', [list, tuple, np.array, Series])
@@ -349,10 +365,13 @@ def test_where_setitem_invalid():
     # GH 2702
     # make sure correct exceptions are raised on invalid list assignment
 
+    msg = ("cannot set using a {} indexer with a different length than"
+           " the value")
+
     # slice
     s = Series(list('abc'))
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg.format('slice')):
         s[0:3] = list(range(27))
 
     s[0:3] = list(range(3))
@@ -362,7 +381,7 @@ def test_where_setitem_invalid():
     # slice with step
     s = Series(list('abcdef'))
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg.format('slice')):
         s[0:4:2] = list(range(27))
 
     s = Series(list('abcdef'))
@@ -373,7 +392,7 @@ def test_where_setitem_invalid():
     # neg slices
     s = Series(list('abcdef'))
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg.format('slice')):
         s[:-1] = list(range(27))
 
     s[-3:-1] = list(range(2))
@@ -383,12 +402,12 @@ def test_where_setitem_invalid():
     # list
     s = Series(list('abc'))
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg.format('list-like')):
         s[[0, 1, 2]] = list(range(27))
 
     s = Series(list('abc'))
 
-    with pytest.raises(ValueError):
+    with pytest.raises(ValueError, match=msg.format('list-like')):
         s[[0, 1, 2]] = list(range(2))
 
     # scalar
@@ -590,8 +609,11 @@ def test_mask():
     rs2 = s2.mask(cond[:3], -s2)
     assert_series_equal(rs, rs2)
 
-    pytest.raises(ValueError, s.mask, 1)
-    pytest.raises(ValueError, s.mask, cond[:3].values, -s)
+    msg = "Array conditional must be same shape as self"
+    with pytest.raises(ValueError, match=msg):
+        s.mask(1)
+    with pytest.raises(ValueError, match=msg):
+        s.mask(cond[:3].values, -s)
 
     # dtype changes
     s = Series([1, 2, 3, 4])

pandas/tests/series/indexing/test_datetime.py

@@ -33,8 +33,8 @@ def test_fancy_getitem():
     assert s['2009-1-2'] == 48
     assert s[datetime(2009, 1, 2)] == 48
     assert s[Timestamp(datetime(2009, 1, 2))] == 48
-    pytest.raises(KeyError, s.__getitem__, '2009-1-3')
-
+    with pytest.raises(KeyError, match=r"^'2009-1-3'$"):
+        s['2009-1-3']
     assert_series_equal(s['3/6/2009':'2009-06-05'],
                         s[datetime(2009, 3, 6):datetime(2009, 6, 5)])
 
@@ -298,7 +298,8 @@ def test_getitem_setitem_datetimeindex():
 
     lb = datetime(1990, 1, 1, 4)
     rb = datetime(1990, 1, 1, 7)
-    with pytest.raises(TypeError):
+    msg = "Cannot compare tz-naive and tz-aware datetime-like objects"
+    with pytest.raises(TypeError, match=msg):
         # tznaive vs tzaware comparison is invalid
         # see GH#18376, GH#18162
         ts[(ts.index >= lb) & (ts.index <= rb)]
@@ -400,15 +401,17 @@ def test_datetime_indexing():
     s = Series(len(index), index=index)
     stamp = Timestamp('1/8/2000')
 
-    pytest.raises(KeyError, s.__getitem__, stamp)
+    with pytest.raises(KeyError, match=r"^947289600000000000$"):
+        s[stamp]
     s[stamp] = 0
     assert s[stamp] == 0
 
     # not monotonic
     s = Series(len(index), index=index)
     s = s[::-1]
 
-    pytest.raises(KeyError, s.__getitem__, stamp)
+    with pytest.raises(KeyError, match=r"^947289600000000000$"):
+        s.__getitem__(stamp)
     s[stamp] = 0
     assert s[stamp] == 0
 
@@ -499,7 +502,8 @@ def test_duplicate_dates_indexing(dups):
         expected = Series(np.where(mask, 0, ts), index=ts.index)
         assert_series_equal(cp, expected)
 
-    pytest.raises(KeyError, ts.__getitem__, datetime(2000, 1, 6))
+    with pytest.raises(KeyError, match=r"^947116800000000000$"):
+        ts[datetime(2000, 1, 6)]
 
     # new index
     ts[datetime(2000, 1, 6)] = 0
@@ -664,8 +668,11 @@ def test_indexing():
     expected = df.loc[[df.index[2]]]
 
     # this is a single date, so will raise
-    pytest.raises(KeyError, df.__getitem__, '2012-01-02 18:01:02', )
-    pytest.raises(KeyError, df.__getitem__, df.index[2], )
+    with pytest.raises(KeyError, match=r"^'2012-01-02 18:01:02'$"):
+        df['2012-01-02 18:01:02']
+    msg = r"Timestamp\('2012-01-02 18:01:02-0600', tz='US/Central', freq='S'\)"
+    with pytest.raises(KeyError, match=msg):
+        df[df.index[2]]
 
 
 """