TST/REF: Add pytest idiom to test_frequencies.py

Author: gfyoung

Diff for: pandas/tests/tseries/frequencies/__init__.py

@@ -0,0 +1,149 @@
+import pytest
+
+from pandas._libs.tslibs import frequencies as libfrequencies, resolution
+from pandas._libs.tslibs.frequencies import (
+    FreqGroup, _period_code_map, get_freq, get_freq_code)
+import pandas.compat as compat
+
+import pandas.tseries.offsets as offsets
+
+
+@pytest.fixture(params=list(compat.iteritems(_period_code_map)))
+def period_code_item(request):
+    return request.param
+
+
+@pytest.mark.parametrize("freqstr,expected", [
+    ("A", 1000), ("3A", 1000), ("-1A", 1000),
+    ("Y", 1000), ("3Y", 1000), ("-1Y", 1000),
+    ("W", 4000), ("W-MON", 4001), ("W-FRI", 4005)
+])
+def test_freq_code(freqstr, expected):
+    assert get_freq(freqstr) == expected
+
+
+def test_freq_code_match(period_code_item):
+    freqstr, code = period_code_item
+    assert get_freq(freqstr) == code
+
+
+@pytest.mark.parametrize("freqstr,expected", [
+    ("A", 1000), ("3A", 1000), ("-1A", 1000), ("A-JAN", 1000),
+    ("A-MAY", 1000), ("Y", 1000), ("3Y", 1000), ("-1Y", 1000),
+    ("Y-JAN", 1000), ("Y-MAY", 1000), (offsets.YearEnd(), 1000),
+    (offsets.YearEnd(month=1), 1000), (offsets.YearEnd(month=5), 1000),
+    ("W", 4000), ("W-MON", 4000), ("W-FRI", 4000), (offsets.Week(), 4000),
+    (offsets.Week(weekday=1), 4000), (offsets.Week(weekday=5), 4000),
+    ("T", FreqGroup.FR_MIN),
+])
+def test_freq_group(freqstr, expected):
+    assert resolution.get_freq_group(freqstr) == expected
+
+
+def test_freq_group_match(period_code_item):
+    freqstr, code = period_code_item
+
+    str_group = resolution.get_freq_group(freqstr)
+    code_group = resolution.get_freq_group(code)
+
+    assert str_group == code_group == code // 1000 * 1000
+
+
+@pytest.mark.parametrize("freqstr,exp_freqstr", [
+    ("D", "D"), ("W", "D"), ("M", "D"),
+    ("S", "S"), ("T", "S"), ("H", "S")
+])
+def test_get_to_timestamp_base(freqstr, exp_freqstr):
+    tsb = libfrequencies.get_to_timestamp_base
+
+    assert tsb(get_freq_code(freqstr)[0]) == get_freq_code(exp_freqstr)[0]
+
+
+_reso = resolution.Resolution
+
+
+@pytest.mark.parametrize("freqstr,expected", [
+    ("A", "year"), ("Q", "quarter"), ("M", "month"),
+    ("D", "day"), ("H", "hour"), ("T", "minute"),
+    ("S", "second"), ("L", "millisecond"),
+    ("U", "microsecond"), ("N", "nanosecond")
+])
+def test_get_str_from_freq(freqstr, expected):
+    assert _reso.get_str_from_freq(freqstr) == expected
+
+
+@pytest.mark.parametrize("freq", ["A", "Q", "M", "D", "H",
+                                  "T", "S", "L", "U", "N"])
+def test_get_freq_roundtrip(freq):
+    result = _reso.get_freq(_reso.get_str_from_freq(freq))
+    assert freq == result
+
+
+@pytest.mark.parametrize("freq", ["D", "H", "T", "S", "L", "U"])
+def test_get_freq_roundtrip2(freq):
+    result = _reso.get_freq(_reso.get_str(_reso.get_reso_from_freq(freq)))
+    assert freq == result
+
+
+@pytest.mark.parametrize("args,expected", [
+    ((1.5, "T"), (90, "S")), ((62.4, "T"), (3744, "S")),
+    ((1.04, "H"), (3744, "S")), ((1, "D"), (1, "D")),
+    ((0.342931, "H"), (1234551600, "U")), ((1.2345, "D"), (106660800, "L"))
+])
+def test_resolution_bumping(args, expected):
+    # see gh-14378
+    assert _reso.get_stride_from_decimal(*args) == expected
+
+
+@pytest.mark.parametrize("args", [
+    (0.5, "N"),
+
+    # Too much precision in the input can prevent.
+    (0.3429324798798269273987982, "H")
+])
+def test_cat(args):
+    msg = "Could not convert to integer offset at any resolution"
+
+    with pytest.raises(ValueError, match=msg):
+        _reso.get_stride_from_decimal(*args)
+
+
+@pytest.mark.parametrize("freq_input,expected", [
+    # Frequency string.
+    ("A", (get_freq("A"), 1)),
+    ("3D", (get_freq("D"), 3)),
+    ("-2M", (get_freq("M"), -2)),
+
+    # Tuple.
+    (("D", 1), (get_freq("D"), 1)),
+    (("A", 3), (get_freq("A"), 3)),
+    (("M", -2), (get_freq("M"), -2)),
+    ((5, "T"), (FreqGroup.FR_MIN, 5)),
+
+    # Numeric Tuple.
+    ((1000, 1), (1000, 1)),
+
+    # Offsets.
+    (offsets.Day(), (get_freq("D"), 1)),
+    (offsets.Day(3), (get_freq("D"), 3)),
+    (offsets.Day(-2), (get_freq("D"), -2)),
+    (offsets.MonthEnd(), (get_freq("M"), 1)),
+    (offsets.MonthEnd(3), (get_freq("M"), 3)),
+    (offsets.MonthEnd(-2), (get_freq("M"), -2)),
+    (offsets.Week(), (get_freq("W"), 1)),
+    (offsets.Week(3), (get_freq("W"), 3)),
+    (offsets.Week(-2), (get_freq("W"), -2)),
+    (offsets.Hour(), (FreqGroup.FR_HR, 1)),
+
+    # Monday is weekday=0.
+    (offsets.Week(weekday=1), (get_freq("W-TUE"), 1)),
+    (offsets.Week(3, weekday=0), (get_freq("W-MON"), 3)),
+    (offsets.Week(-2, weekday=4), (get_freq("W-FRI"), -2)),
+])
+def test_get_freq_code(freq_input, expected):
+    assert get_freq_code(freq_input) == expected
+
+
+def test_get_code_invalid():
+    with pytest.raises(ValueError, match="Invalid frequency"):
+        get_freq_code((5, "baz"))