STY: use pytest.raises context manager (tests/test_*)

pandas/tests/test_algos.py

@@ -11,7 +11,7 @@
 
 from pandas._libs import (
     algos as libalgos, groupby as libgroupby, hashtable as ht)
-from pandas.compat import lrange, range
+from pandas.compat import PY2, lrange, range
 from pandas.compat.numpy import np_array_datetime64_compat
 import pandas.util._test_decorators as td
 
@@ -224,11 +224,16 @@ def test_factorize_tuple_list(self, data, expected_label, expected_level):
                                                      dtype=object)
         tm.assert_numpy_array_equal(result[1], expected_level_array)
 
+    @pytest.mark.skipif(PY2, reason="pytest.raises match regex fails")
     def test_complex_sorting(self):
         # gh 12666 - check no segfault
         x17 = np.array([complex(i) for i in range(17)], dtype=object)
 
-        pytest.raises(TypeError, algos.factorize, x17[::-1], sort=True)
+        msg = ("'<' not supported between instances of 'complex' and"
+               r" 'complex'|"
+               r"unorderable types: complex\(\) > complex\(\)")
+        with pytest.raises(TypeError, match=msg):
+            algos.factorize(x17[::-1], sort=True)
 
     def test_float64_factorize(self, writable):
         data = np.array([1.0, 1e8, 1.0, 1e-8, 1e8, 1.0], dtype=np.float64)
@@ -589,9 +594,14 @@ class TestIsin(object):
 
     def test_invalid(self):
 
-        pytest.raises(TypeError, lambda: algos.isin(1, 1))
-        pytest.raises(TypeError, lambda: algos.isin(1, [1]))
-        pytest.raises(TypeError, lambda: algos.isin([1], 1))
+        msg = (r"only list-like objects are allowed to be passed to isin\(\),"
+               r" you passed a \[int\]")
+        with pytest.raises(TypeError, match=msg):
+            algos.isin(1, 1)
+        with pytest.raises(TypeError, match=msg):
+            algos.isin(1, [1])
+        with pytest.raises(TypeError, match=msg):
+            algos.isin([1], 1)
 
     def test_basic(self):
 
@@ -819,8 +829,9 @@ def test_value_counts_dtypes(self):
         result = algos.value_counts(Series([1, 1., '1']))  # object
         assert len(result) == 2
 
-        pytest.raises(TypeError, lambda s: algos.value_counts(s, bins=1),
-                      ['1', 1])
+        msg = "bins argument only works with numeric data"
+        with pytest.raises(TypeError, match=msg):
+            algos.value_counts(['1', 1], bins=1)
 
     def test_value_counts_nat(self):
         td = Series([np.timedelta64(10000), pd.NaT], dtype='timedelta64[ns]')

pandas/tests/test_config.py

@@ -3,7 +3,10 @@
 
 import pytest
 
+from pandas.compat import PY2
+
 import pandas as pd
+from pandas.core.config import OptionError
 
 
 class TestConfig(object):
@@ -48,26 +51,35 @@ def test_is_one_of_factory(self):
 
         v(12)
         v(None)
-        pytest.raises(ValueError, v, 1.1)
+        msg = r"Value must be one of None\|12"
+        with pytest.raises(ValueError, match=msg):
+            v(1.1)
 
     def test_register_option(self):
         self.cf.register_option('a', 1, 'doc')
 
         # can't register an already registered option
-        pytest.raises(KeyError, self.cf.register_option, 'a', 1, 'doc')
+        msg = "Option 'a' has already been registered"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.register_option('a', 1, 'doc')
 
         # can't register an already registered option
-        pytest.raises(KeyError, self.cf.register_option, 'a.b.c.d1', 1,
-                      'doc')
-        pytest.raises(KeyError, self.cf.register_option, 'a.b.c.d2', 1,
-                      'doc')
+        msg = "Path prefix to option 'a' is already an option"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.register_option('a.b.c.d1', 1, 'doc')
+        with pytest.raises(OptionError, match=msg):
+            self.cf.register_option('a.b.c.d2', 1, 'doc')
 
         # no python keywords
-        pytest.raises(ValueError, self.cf.register_option, 'for', 0)
-        pytest.raises(ValueError, self.cf.register_option, 'a.for.b', 0)
+        msg = "for is a python keyword"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.register_option('for', 0)
+        with pytest.raises(ValueError, match=msg):
+            self.cf.register_option('a.for.b', 0)
         # must be valid identifier (ensure attribute access works)
-        pytest.raises(ValueError, self.cf.register_option,
-                      'Oh my Goddess!', 0)
+        msg = "oh my goddess! is not a valid identifier"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.register_option('Oh my Goddess!', 0)
 
         # we can register options several levels deep
         # without predefining the intermediate steps
@@ -90,7 +102,9 @@ def test_describe_option(self):
         self.cf.register_option('l', "foo")
 
         # non-existent keys raise KeyError
-        pytest.raises(KeyError, self.cf.describe_option, 'no.such.key')
+        msg = r"No such keys\(s\)"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.describe_option('no.such.key')
 
         # we can get the description for any key we registered
         assert 'doc' in self.cf.describe_option('a', _print_desc=False)
@@ -122,7 +136,9 @@ def test_case_insensitive(self):
         assert self.cf.get_option('kAnBaN') == 2
 
         # gets of non-existent keys fail
-        pytest.raises(KeyError, self.cf.get_option, 'no_such_option')
+        msg = r"No such keys\(s\): 'no_such_option'"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.get_option('no_such_option')
         self.cf.deprecate_option('KanBan')
 
         assert self.cf._is_deprecated('kAnBaN')
@@ -138,7 +154,9 @@ def test_get_option(self):
         assert self.cf.get_option('b.b') is None
 
         # gets of non-existent keys fail
-        pytest.raises(KeyError, self.cf.get_option, 'no_such_option')
+        msg = r"No such keys\(s\): 'no_such_option'"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.get_option('no_such_option')
 
     def test_set_option(self):
         self.cf.register_option('a', 1, 'doc')
@@ -157,16 +175,24 @@ def test_set_option(self):
         assert self.cf.get_option('b.c') == 'wurld'
         assert self.cf.get_option('b.b') == 1.1
 
-        pytest.raises(KeyError, self.cf.set_option, 'no.such.key', None)
+        msg = r"No such keys\(s\): 'no.such.key'"
+        with pytest.raises(OptionError, match=msg):
+            self.cf.set_option('no.such.key', None)
 
     def test_set_option_empty_args(self):
-        pytest.raises(ValueError, self.cf.set_option)
+        msg = "Must provide an even number of non-keyword arguments"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option()
 
     def test_set_option_uneven_args(self):
-        pytest.raises(ValueError, self.cf.set_option, 'a.b', 2, 'b.c')
+        msg = "Must provide an even number of non-keyword arguments"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option('a.b', 2, 'b.c')
 
     def test_set_option_invalid_single_argument_type(self):
-        pytest.raises(ValueError, self.cf.set_option, 2)
+        msg = "Must provide an even number of non-keyword arguments"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option(2)
 
     def test_set_option_multiple(self):
         self.cf.register_option('a', 1, 'doc')
@@ -183,27 +209,36 @@ def test_set_option_multiple(self):
         assert self.cf.get_option('b.c') is None
         assert self.cf.get_option('b.b') == 10.0
 
+    @pytest.mark.skipif(PY2, reason="pytest.raises match regex fails")
     def test_validation(self):
         self.cf.register_option('a', 1, 'doc', validator=self.cf.is_int)
         self.cf.register_option('b.c', 'hullo', 'doc2',
                                 validator=self.cf.is_text)
-        pytest.raises(ValueError, self.cf.register_option, 'a.b.c.d2',
-                      'NO', 'doc', validator=self.cf.is_int)
+        msg = "Value must have type '<class 'int'>'"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.register_option(
+                'a.b.c.d2', 'NO', 'doc', validator=self.cf.is_int)
 
         self.cf.set_option('a', 2)  # int is_int
         self.cf.set_option('b.c', 'wurld')  # str is_str
 
-        pytest.raises(
-            ValueError, self.cf.set_option, 'a', None)  # None not is_int
-        pytest.raises(ValueError, self.cf.set_option, 'a', 'ab')
-        pytest.raises(ValueError, self.cf.set_option, 'b.c', 1)
+        # None not is_int
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option('a', None)
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option('a', 'ab')
+
+        msg = r"Value must be an instance of <class 'str'>\|<class 'bytes'>"
+        with pytest.raises(ValueError, match=msg):
+            self.cf.set_option('b.c', 1)
 
         validator = self.cf.is_one_of_factory([None, self.cf.is_callable])
         self.cf.register_option('b', lambda: None, 'doc',
                                 validator=validator)
         self.cf.set_option('b', '%.1f'.format)  # Formatter is callable
         self.cf.set_option('b', None)  # Formatter is none (default)
-        pytest.raises(ValueError, self.cf.set_option, 'b', '%.1f')
+        with pytest.raises(ValueError, match="Value must be a callable"):
+            self.cf.set_option('b', '%.1f')
 
     def test_reset_option(self):
         self.cf.register_option('a', 1, 'doc', validator=self.cf.is_int)
@@ -267,8 +302,9 @@ def test_deprecate_option(self):
             assert 'eprecated' in str(w[-1])  # we get the default message
             assert 'nifty_ver' in str(w[-1])  # with the removal_ver quoted
 
-            pytest.raises(
-                KeyError, self.cf.deprecate_option, 'a')  # can't depr. twice
+            msg = "Option 'a' has already been defined as deprecated"
+            with pytest.raises(OptionError, match=msg):
+                self.cf.deprecate_option('a')
 
         self.cf.deprecate_option('b.c', 'zounds!')
         with warnings.catch_warnings(record=True) as w:
@@ -374,12 +410,6 @@ def eq(val):
     def test_attribute_access(self):
         holder = []
 
-        def f():
-            options.b = 1
-
-        def f2():
-            options.display = 1
-
         def f3(key):
             holder.append(True)
 
@@ -397,8 +427,11 @@ def f3(key):
         self.cf.reset_option("a")
         assert options.a == self.cf.get_option("a", 0)
 
-        pytest.raises(KeyError, f)
-        pytest.raises(KeyError, f2)
+        msg = "You can only set the value of existing options"
+        with pytest.raises(OptionError, match=msg):
+            options.b = 1
+        with pytest.raises(OptionError, match=msg):
+            options.display = 1
 
         # make sure callback kicks when using this form of setting
         options.c = 1
@@ -429,5 +462,6 @@ def test_option_context_scope(self):
     def test_dictwrapper_getattr(self):
         options = self.cf.options
         # GH 19789
-        pytest.raises(self.cf.OptionError, getattr, options, 'bananas')
+        with pytest.raises(OptionError, match="No such option"):
+            options.bananas
         assert not hasattr(options, 'bananas')

pandas/tests/test_multilevel.py

@@ -886,8 +886,11 @@ def test_count(self):
         tm.assert_series_equal(result, expect, check_names=False)
         assert result.index.name == 'a'
 
-        pytest.raises(KeyError, series.count, 'x')
-        pytest.raises(KeyError, frame.count, level='x')
+        msg = "Level x not found"
+        with pytest.raises(KeyError, match=msg):
+            series.count('x')
+        with pytest.raises(KeyError, match=msg):
+            frame.count(level='x')
 
     @pytest.mark.parametrize('op', AGG_FUNCTIONS)
     @pytest.mark.parametrize('level', [0, 1])
@@ -1119,7 +1122,8 @@ def test_level_with_tuples(self):
         tm.assert_series_equal(result, expected)
         tm.assert_series_equal(result2, expected)
 
-        pytest.raises(KeyError, series.__getitem__, (('foo', 'bar', 0), 2))
+        with pytest.raises(KeyError, match=r"^\(\('foo', 'bar', 0\), 2\)$"):
+            series[('foo', 'bar', 0), 2]
 
         result = frame.loc[('foo', 'bar', 0)]
         result2 = frame.xs(('foo', 'bar', 0))

pandas/tests/test_nanops.py

@@ -7,6 +7,7 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PY2
 from pandas.compat.numpy import _np_version_under1p13
 import pandas.util._test_decorators as td
 
@@ -728,6 +729,7 @@ def test_numeric_values(self):
         # Test complex
         assert nanops._ensure_numeric(1 + 2j) == 1 + 2j
 
+    @pytest.mark.skipif(PY2, reason="pytest.raises match regex fails")
     def test_ndarray(self):
         # Test numeric ndarray
         values = np.array([1, 2, 3])
@@ -743,17 +745,25 @@ def test_ndarray(self):
 
         # Test non-convertible string ndarray
         s_values = np.array(['foo', 'bar', 'baz'], dtype=object)
-        pytest.raises(ValueError, lambda: nanops._ensure_numeric(s_values))
+        msg = r"could not convert string to float: '(foo|baz)'"
+        with pytest.raises(ValueError, match=msg):
+            nanops._ensure_numeric(s_values)
 
     def test_convertable_values(self):
         assert np.allclose(nanops._ensure_numeric('1'), 1.0)
         assert np.allclose(nanops._ensure_numeric('1.1'), 1.1)
         assert np.allclose(nanops._ensure_numeric('1+1j'), 1 + 1j)
 
     def test_non_convertable_values(self):
-        pytest.raises(TypeError, lambda: nanops._ensure_numeric('foo'))
-        pytest.raises(TypeError, lambda: nanops._ensure_numeric({}))
-        pytest.raises(TypeError, lambda: nanops._ensure_numeric([]))
+        msg = "Could not convert foo to numeric"
+        with pytest.raises(TypeError, match=msg):
+            nanops._ensure_numeric('foo')
+        msg = "Could not convert {} to numeric"
+        with pytest.raises(TypeError, match=msg):
+            nanops._ensure_numeric({})
+        msg = r"Could not convert \[\] to numeric"
+        with pytest.raises(TypeError, match=msg):
+            nanops._ensure_numeric([])
 
 
 class TestNanvarFixedValues(object):

pandas/tests/test_sorting.py

@@ -7,6 +7,8 @@
 from numpy import nan
 import pytest
 
+from pandas.compat import PY2
+
 from pandas import DataFrame, MultiIndex, Series, compat, concat, merge
 from pandas.core import common as com
 from pandas.core.sorting import (
@@ -403,15 +405,21 @@ def test_mixed_integer_from_list(self):
         expected = np.array([0, 0, 1, 'a', 'b', 'b'], dtype=object)
         tm.assert_numpy_array_equal(result, expected)
 
+    @pytest.mark.skipif(PY2, reason="pytest.raises match regex fails")
     def test_unsortable(self):
         # GH 13714
         arr = np.array([1, 2, datetime.now(), 0, 3], dtype=object)
+        msg = ("'<' not supported between instances of 'datetime.datetime'"
+               r" and 'int'|"
+               r"unorderable types: int\(\) > datetime.datetime\(\)")
         if compat.PY2:
             # RuntimeWarning: tp_compare didn't return -1 or -2 for exception
             with warnings.catch_warnings():
-                pytest.raises(TypeError, safe_sort, arr)
+                with pytest.raises(TypeError, match=msg):
+                    safe_sort(arr)
         else:
-            pytest.raises(TypeError, safe_sort, arr)
+            with pytest.raises(TypeError, match=msg):
+                safe_sort(arr)
 
     def test_exceptions(self):
         with pytest.raises(TypeError,