STY: use pytest.raises context manager (resample) (#24977)

Author: simonjayhawkins

pandas/tests/resample/test_base.py

@@ -95,7 +95,10 @@ def test_resample_interpolate_all_ts(frame):
 def test_raises_on_non_datetimelike_index():
  # this is a non datetimelike index
  xp = DataFrame()
- pytest.raises(TypeError, lambda: xp.resample('A').mean())
+ msg = ("Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex,"
+ " but got an instance of 'Index'")
+ with pytest.raises(TypeError, match=msg):
+ xp.resample('A').mean()
 
 
 @pytest.mark.parametrize('freq', ['M', 'D', 'H'])
@@ -189,8 +192,10 @@ def test_resample_loffset_arg_type_all_ts(frame, create_index):
 
  # GH 13022, 7687 - TODO: fix resample w/ TimedeltaIndex
  if isinstance(expected.index, TimedeltaIndex):
- with pytest.raises(AssertionError):
+ msg = "DataFrame are different"
+ with pytest.raises(AssertionError, match=msg):
  assert_frame_equal(result_agg, expected)
+ with pytest.raises(AssertionError, match=msg):
  assert_frame_equal(result_how, expected)
  else:
  assert_frame_equal(result_agg, expected)

pandas/tests/resample/test_datetime_index.py

@@ -113,16 +113,18 @@ def test_resample_basic_grouper(series):
 @pytest.mark.parametrize(
  '_index_start,_index_end,_index_name',
  [('1/1/2000 00:00:00', '1/1/2000 00:13:00', 'index')])
-@pytest.mark.parametrize('kwargs', [
- dict(label='righttt'),
- dict(closed='righttt'),
- dict(convention='starttt')
+@pytest.mark.parametrize('keyword,value', [
+ ('label', 'righttt'),
+ ('closed', 'righttt'),
+ ('convention', 'starttt')
 ])
-def test_resample_string_kwargs(series, kwargs):
+def test_resample_string_kwargs(series, keyword, value):
  # see gh-19303
  # Check that wrong keyword argument strings raise an error
- with pytest.raises(ValueError, match='Unsupported value'):
- series.resample('5min', **kwargs)
+ msg = "Unsupported value {value} for `{keyword}`".format(
+ value=value, keyword=keyword)
+ with pytest.raises(ValueError, match=msg):
+ series.resample('5min', **({keyword: value}))
 
 
 @pytest.mark.parametrize(
@@ -676,7 +678,7 @@ def test_asfreq_non_unique():
  ts = Series(np.random.randn(len(rng2)), index=rng2)
 
  msg = 'cannot reindex from a duplicate axis'
- with pytest.raises(Exception, match=msg):
+ with pytest.raises(ValueError, match=msg):
  ts.asfreq('B')
 
 

pandas/tests/resample/test_period_index.py

@@ -11,6 +11,7 @@
 
 import pandas as pd
 from pandas import DataFrame, Series, Timestamp
+from pandas.core.indexes.base import InvalidIndexError
 from pandas.core.indexes.datetimes import date_range
 from pandas.core.indexes.period import Period, PeriodIndex, period_range
 from pandas.core.resample import _get_period_range_edges
@@ -72,17 +73,19 @@ def test_asfreq_fill_value(self, series):
 
  @pytest.mark.parametrize('freq', ['H', '12H', '2D', 'W'])
  @pytest.mark.parametrize('kind', [None, 'period', 'timestamp'])
- def test_selection(self, index, freq, kind):
+ @pytest.mark.parametrize('kwargs', [dict(on='date'), dict(level='d')])
+ def test_selection(self, index, freq, kind, kwargs):
  # This is a bug, these should be implemented
  # GH 14008
  rng = np.arange(len(index), dtype=np.int64)
  df = DataFrame({'date': index, 'a': rng},
  index=pd.MultiIndex.from_arrays([rng, index],
  names=['v', 'd']))
- with pytest.raises(NotImplementedError):
- df.resample(freq, on='date', kind=kind)
- with pytest.raises(NotImplementedError):
- df.resample(freq, level='d', kind=kind)
+ msg = ("Resampling from level= or on= selection with a PeriodIndex is"
+ r" not currently supported, use \.set_index\(\.\.\.\) to"
+ " explicitly set index")
+ with pytest.raises(NotImplementedError, match=msg):
+ df.resample(freq, kind=kind, **kwargs)
 
  @pytest.mark.parametrize('month', MONTHS)
  @pytest.mark.parametrize('meth', ['ffill', 'bfill'])
@@ -110,13 +113,20 @@ def test_basic_downsample(self, simple_period_range_series):
  assert_series_equal(ts.resample('a-dec').mean(), result)
  assert_series_equal(ts.resample('a').mean(), result)
 
- def test_not_subperiod(self, simple_period_range_series):
+ @pytest.mark.parametrize('rule,expected_error_msg', [
+ ('a-dec', '<YearEnd: month=12>'),
+ ('q-mar', '<QuarterEnd: startingMonth=3>'),
+ ('M', '<MonthEnd>'),
+ ('w-thu', '<Week: weekday=3>')
+ ])
+ def test_not_subperiod(
+ self, simple_period_range_series, rule, expected_error_msg):
  # These are incompatible period rules for resampling
  ts = simple_period_range_series('1/1/1990', '6/30/1995', freq='w-wed')
- pytest.raises(ValueError, lambda: ts.resample('a-dec').mean())
- pytest.raises(ValueError, lambda: ts.resample('q-mar').mean())
- pytest.raises(ValueError, lambda: ts.resample('M').mean())
- pytest.raises(ValueError, lambda: ts.resample('w-thu').mean())
+ msg = ("Frequency <Week: weekday=2> cannot be resampled to {}, as they"
+  " are not sub or super periods").format(expected_error_msg)
+ with pytest.raises(IncompatibleFrequency, match=msg):
+  ts.resample(rule).mean()
 
  @pytest.mark.parametrize('freq', ['D', '2D'])
  def test_basic_upsample(self, freq, simple_period_range_series):
@@ -212,8 +222,9 @@ def test_resample_same_freq(self, resample_method):
  assert_series_equal(result, expected)
 
  def test_resample_incompat_freq(self):
-
- with pytest.raises(IncompatibleFrequency):
+ msg = ("Frequency <MonthEnd> cannot be resampled to <Week: weekday=6>,"
+ " as they are not sub or super periods")
+ with pytest.raises(IncompatibleFrequency, match=msg):
  Series(range(3), index=pd.period_range(
  start='2000', periods=3, freq='M')).resample('W').mean()
 
@@ -373,7 +384,9 @@ def test_resample_fill_missing(self):
  def test_cant_fill_missing_dups(self):
  rng = PeriodIndex([2000, 2005, 2005, 2007, 2007], freq='A')
  s = Series(np.random.randn(5), index=rng)
- pytest.raises(Exception, lambda: s.resample('A').ffill())
+ msg = "Reindexing only valid with uniquely valued Index objects"
+ with pytest.raises(InvalidIndexError, match=msg):
+ s.resample('A').ffill()
 
  @pytest.mark.parametrize('freq', ['5min'])
  @pytest.mark.parametrize('kind', ['period', None, 'timestamp'])

pandas/tests/resample/test_resample_api.py

@@ -113,16 +113,14 @@ def test_getitem():
  test_frame.columns[[0, 1]])
 
 
-def test_select_bad_cols():
-
+@pytest.mark.parametrize('key', [['D'], ['A', 'D']])
+def test_select_bad_cols(key):
  g = test_frame.resample('H')
- pytest.raises(KeyError, g.__getitem__, ['D'])
-
- pytest.raises(KeyError, g.__getitem__, ['A', 'D'])
- with pytest.raises(KeyError, match='^[^A]+$'):
- # A should not be referenced as a bad column...
- # will have to rethink regex if you change message!
- g[['A', 'D']]
+ # 'A' should not be referenced as a bad column...
+ # will have to rethink regex if you change message!
+ msg = r"^\"Columns not found: 'D'\"$"
+ with pytest.raises(KeyError, match=msg):
+ g[key]
 
 
 def test_attribute_access():
@@ -216,7 +214,9 @@ def test_fillna():
  result = r.fillna(method='bfill')
  assert_series_equal(result, expected)
 
- with pytest.raises(ValueError):
+ msg = (r"Invalid fill method\. Expecting pad \(ffill\), backfill"
+ r" \(bfill\) or nearest\. Got 0")
+ with pytest.raises(ValueError, match=msg):
  r.fillna(0)
 
 
@@ -437,12 +437,11 @@ def test_agg_misc():
 
  # errors
  # invalid names in the agg specification
+ msg = "\"Column 'B' does not exist!\""
  for t in cases:
- with pytest.raises(KeyError):
- with tm.assert_produces_warning(FutureWarning,
- check_stacklevel=False):
- t[['A']].agg({'A': ['sum', 'std'],
- 'B': ['mean', 'std']})
+ with pytest.raises(KeyError, match=msg):
+ t[['A']].agg({'A': ['sum', 'std'],
+ 'B': ['mean', 'std']})
 
 
 def test_agg_nested_dicts():
@@ -464,11 +463,11 @@ def test_agg_nested_dicts():
  df.groupby(pd.Grouper(freq='2D'))
  ]
 
+ msg = r"cannot perform renaming for r(1|2) with a nested dictionary"
  for t in cases:
- def f():
+ with pytest.raises(pd.core.base.SpecificationError, match=msg):
  t.aggregate({'r1': {'A': ['mean', 'sum']},
  'r2': {'B': ['mean', 'sum']}})
- pytest.raises(ValueError, f)
 
  for t in cases:
  expected = pd.concat([t['A'].mean(), t['A'].std(), t['B'].mean(),
@@ -499,7 +498,8 @@ def test_try_aggregate_non_existing_column():
  df = DataFrame(data).set_index('dt')
 
  # Error as we don't have 'z' column
- with pytest.raises(KeyError):
+ msg = "\"Column 'z' does not exist!\""
+ with pytest.raises(KeyError, match=msg):
  df.resample('30T').agg({'x': ['mean'],
  'y': ['median'],
  'z': ['sum']})
@@ -517,23 +517,29 @@ def test_selection_api_validation():
  df_exp = DataFrame({'a': rng}, index=index)
 
  # non DatetimeIndex
- with pytest.raises(TypeError):
+ msg = ("Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex,"
+ " but got an instance of 'Int64Index'")
+ with pytest.raises(TypeError, match=msg):
  df.resample('2D', level='v')
 
- with pytest.raises(ValueError):
+ msg = "The Grouper cannot specify both a key and a level!"
+ with pytest.raises(ValueError, match=msg):
  df.resample('2D', on='date', level='d')
 
- with pytest.raises(TypeError):
+ msg = "unhashable type: 'list'"
+ with pytest.raises(TypeError, match=msg):
  df.resample('2D', on=['a', 'date'])
 
- with pytest.raises(KeyError):
+ msg = r"\"Level \['a', 'date'\] not found\""
+ with pytest.raises(KeyError, match=msg):
  df.resample('2D', level=['a', 'date'])
 
  # upsampling not allowed
- with pytest.raises(ValueError):
+ msg = ("Upsampling from level= or on= selection is not supported, use"
+ r" \.set_index\(\.\.\.\) to explicitly set index to datetime-like")
+ with pytest.raises(ValueError, match=msg):
  df.resample('2D', level='d').asfreq()
-
- with pytest.raises(ValueError):
+ with pytest.raises(ValueError, match=msg):
  df.resample('2D', on='date').asfreq()
 
  exp = df_exp.resample('2D').sum()

pandas/tests/resample/test_time_grouper.py

@@ -112,7 +112,7 @@ def test_fails_on_no_datetime_index(name, func):
  df = DataFrame({'a': np.random.randn(n)}, index=index)
 
  msg = ("Only valid with DatetimeIndex, TimedeltaIndex "
- "or PeriodIndex, but got an instance of %r" % name)
+ "or PeriodIndex, but got an instance of '{}'".format(name))
  with pytest.raises(TypeError, match=msg):
  df.groupby(TimeGrouper('D'))