diff options
| -rw-r--r-- | poezio/common.py | 20 | ||||
| -rw-r--r-- | test/test_common.py | 21 |
2 files changed, 40 insertions, 1 deletions
diff --git a/poezio/common.py b/poezio/common.py index ba179310..7cddc306 100644 --- a/poezio/common.py +++ b/poezio/common.py @@ -17,6 +17,7 @@ import subprocess import time import string import logging +import itertools from slixmpp import JID, InvalidJID, Message from poezio.poezio_shlex import shlex @@ -468,3 +469,22 @@ def safeJID(*args, **kwargs) -> JID: exc_info=True, ) return JID('') + + +def unique_prefix_of(a: str, b: str) -> str: + """ + Return the unique prefix of `a` with `b`. + + Corner cases: + + * If `a` and `b` share no prefix, the first letter of `a` is returned. + * If `a` and `b` are equal, `a` is returned. + * If `a` is a prefix of `b`, `a` is returned. + * If `b` is a prefix of `a`, `b` plus the first letter of `a` after the + common prefix is returned. + """ + for i, (ca, cb) in enumerate(itertools.zip_longest(a, b)): + if ca != cb: + return a[:i+1] + # both are equal, return a + return a diff --git a/test/test_common.py b/test/test_common.py index d7bc2b8b..b6560fc9 100644 --- a/test/test_common.py +++ b/test/test_common.py @@ -11,7 +11,7 @@ from poezio.common import (_datetime_tuple as datetime_tuple, get_utc_time, get_local_time, shell_split, _find_argument_quoted as find_argument_quoted, _find_argument_unquoted as find_argument_unquoted, parse_str_to_secs, - parse_secs_to_str, safeJID) + parse_secs_to_str, safeJID, unique_prefix_of) def test_utc_time(): delta = timedelta(seconds=-3600) @@ -63,3 +63,22 @@ def test_parse_secs_to_str(): def test_safeJID(): assert safeJID('toto@titi/tata') == JID('toto@titi/tata') assert safeJID('toto@…') == JID('') + +def test_unique_prefix_of__no_shared_prefix(): + assert unique_prefix_of("a", "b") == "a" + assert unique_prefix_of("foo", "bar") == "f" + assert unique_prefix_of("foo", "") == "f" + +def test_unique_prefix_of__equal(): + assert unique_prefix_of("foo", "foo") == "foo" + +def test_unique_prefix_of__a_prefix(): + assert unique_prefix_of("foo", "foobar") == "foo" + +def test_unique_prefix_of__b_prefix(): + assert unique_prefix_of("foobar", "foo") == "foob" + +def test_unique_prefix_of__normal_shared_prefix(): + assert unique_prefix_of("foobar", "foobaz") == "foobar" + assert unique_prefix_of("fnord", "funky") == "fn" + assert unique_prefix_of("asbestos", "aspergers") == "asb" |