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| author | Aleksei Strizhak <alexei.mifrill.strizhak@gmail.com> | 2021-10-12 14:58:53 +0500 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-10-12 11:58:53 +0200 |
| commit | 83ec82cb5e032ab31e5aae49902cf61be38ddfc2 (patch) | |
| tree | 22d3753a64630468c732011e6b4ca857b3afd136 | |
| parent | 994f3665c2e822cde71c93cdb71e21416442e735 (diff) | |
| download | dateutil-git-83ec82cb5e032ab31e5aae49902cf61be38ddfc2.tar.gz | |
Document behavior when time delta addition falls after end of month
Document potentially surprising behaviour and add tests to cover these cases.
| -rw-r--r-- | AUTHORS.md | 1 | ||||
| -rw-r--r-- | changelog.d/1167.doc.rst | 3 | ||||
| -rw-r--r-- | docs/relativedelta.rst | 9 | ||||
| -rw-r--r-- | tests/test_relativedelta.py | 61 |
4 files changed, 74 insertions, 0 deletions
@@ -15,6 +15,7 @@ switch, and thus all their contributions are dual-licensed. - Adrien Cossa <cossa@MASKED> - Alec Nikolas Reiter <alecreiter@MASKED> - Alec Reiter <areiter@MASKED> +- Aleksei Strizhak <alexei.mifrill.strizhak@MASKED> (gh: @Mifrill) - Alex Chamberlain (gh: @alexchamberlain) **D** - Alex Verdyan <verdyan@MASKED> - Alex Willmer <alex@moreati.org.uk> (gh: @moreati) **R** diff --git a/changelog.d/1167.doc.rst b/changelog.d/1167.doc.rst new file mode 100644 index 0000000..36def3b --- /dev/null +++ b/changelog.d/1167.doc.rst @@ -0,0 +1,3 @@ +Added note into docs and tests where relativedelta would return last day of the month +only if the same day on a different month resolves to a date that doesn't exist. +Reported by @hawkEye-01 (gh issue #1167). Fixed by @Mifrill (gh pr #1168)
\ No newline at end of file diff --git a/docs/relativedelta.rst b/docs/relativedelta.rst index 0899f34..e2994d2 100644 --- a/docs/relativedelta.rst +++ b/docs/relativedelta.rst @@ -91,6 +91,15 @@ boundary. The logic for years is the same, even on leap years. +If the result falls on a day after the last one of the month, the last day of the month is used instead. + +.. doctest:: + + >>> date(2003,1,30)+relativedelta(months=+1) + datetime.date(2003, 2, 28) + >>> date(2003,5,31)+relativedelta(months=-1) + datetime.date(2003, 4, 30) + .. doctest:: relativedelta >>> date(2000,2,28)+relativedelta(years=+1) diff --git a/tests/test_relativedelta.py b/tests/test_relativedelta.py index 1e5d170..5204c29 100644 --- a/tests/test_relativedelta.py +++ b/tests/test_relativedelta.py @@ -650,6 +650,67 @@ class RelativeDeltaTest(unittest.TestCase): except: self.fail("relativedelta() failed to hash!") + def testDayOfMonthPlus(self): + assert [ + date(2021, 1, 28) + relativedelta(months=1), + date(2021, 2, 27) + relativedelta(months=1), + date(2021, 4, 29) + relativedelta(months=1), + date(2021, 5, 30) + relativedelta(months=1), + ] == [ + date(2021, 2, 28), + date(2021, 3, 27), + date(2021, 5, 29), + date(2021, 6, 30), + ] + + def testLastDayOfMonthPlus(self): + assert [ + date(2021, 1, 31) + relativedelta(months=1), + date(2021, 1, 30) + relativedelta(months=1), + date(2021, 1, 29) + relativedelta(months=1), + date(2021, 1, 28) + relativedelta(months=1), + date(2021, 2, 28) + relativedelta(months=1), + date(2021, 4, 30) + relativedelta(months=1), + date(2021, 5, 31) + relativedelta(months=1), + ] == [ + date(2021, 2, 28), + date(2021, 2, 28), + date(2021, 2, 28), + date(2021, 2, 28), + date(2021, 3, 28), + date(2021, 5, 30), + date(2021, 6, 30), + ] + + def testDayOfMonthMinus(self): + assert [ + date(2021, 2, 27) - relativedelta(months=1), + date(2021, 3, 30) - relativedelta(months=1), + date(2021, 3, 29) - relativedelta(months=1), + date(2021, 3, 28) - relativedelta(months=1), + date(2021, 5, 30) - relativedelta(months=1), + date(2021, 6, 29) - relativedelta(months=1), + ] == [ + date(2021, 1, 27), + date(2021, 2, 28), + date(2021, 2, 28), + date(2021, 2, 28), + date(2021, 4, 30), + date(2021, 5, 29), + ] + + def testLastDayOfMonthMinus(self): + assert [ + date(2021, 2, 28) - relativedelta(months=1), + date(2021, 3, 31) - relativedelta(months=1), + date(2021, 5, 31) - relativedelta(months=1), + date(2021, 6, 30) - relativedelta(months=1), + ] == [ + date(2021, 1, 28), + date(2021, 2, 28), + date(2021, 4, 30), + date(2021, 5, 30), + ] class RelativeDeltaWeeksPropertyGetterTest(unittest.TestCase): """Test the weeks property getter""" |