Add utils for poetry/semver

- boolean check for a sem-ver string
- filter and sort a sequence of sem-ver strings

poetry/semver/semver_utils.py

@@ -0,0 +1,44 @@
+"""
+Strict SEM-VER utilities
+
+The focus of this module is only on sem-ver support and not
+full PEP-0440 support, which is not compatible with all the
+SEM-VER specs.
+
+https://legacy.python.org/dev/peps/pep-0440/#semantic-versioning
+> Semantic versions containing a hyphen (pre-releases - clause 10) or
+> a plus sign (builds - clause 11) are not compatible with this PEP
+> and are not permitted in the public version field.
+"""
+
+from typing import List
+from typing import Optional
+
+import semver
+
+
+def is_semver(value):  # type: (str) -> bool
+    """Check that a string is a single SEM-VER identifier
+
+    :param value: a single SEM-VER identifier
+    :return: True if value is a single SEM-VER identifier
+    """
+    try:
+        semver.VersionInfo.parse(value)
+        return True
+    except (TypeError, ValueError):
+        return False
+
+
+def sorted_semver(
+    values, reverse=False
+):  # type: (List[str], Optional[bool]) -> List[str]
+    """Sort a list of single SEM-VER constraints (string);
+    discards any string that is not a SEM-VER identifier.
+
+    :param values: a list of single SEM-VER identifiers (strings)
+    :param reverse: sort descending (reverse=True) or ascending (reverse=False)
+    :return: sorted values based on SEM-VER sort criteria
+    """
+    unsorted = [ver for ver in values if is_semver(ver)]
+    return sorted(unsorted, key=semver.VersionInfo.parse, reverse=reverse)

tests/semver/test_semver_utils.py

@@ -0,0 +1,73 @@
+import random
+
+import pytest
+import semver
+
+from poetry.semver.semver_utils import is_semver
+from poetry.semver.semver_utils import sorted_semver
+
+# semver sorted values, from
+# https://github.com/k-bx/python-semver/blob/master/test_semver.py
+SORTED = [
+    "1.0.0-alpha",
+    "1.0.0-alpha.1",
+    "1.0.0-alpha.beta",
+    "1.0.0-beta",
+    "1.0.0-beta.2",
+    "1.0.0-beta.11",
+    "1.0.0-rc.1",
+    "1.0.0",
+    "1.0.0",
+    "2.0.0",
+]
+
+
+@pytest.mark.parametrize(
+    "version,result",
+    [
+        ("1.2.3-alpha.1.2+build.11.e0f985a", True),
+        ("2.0.0", True),
+        ("1.0.0", True),
+        ("1.0.0-alpha.1", True),
+        ("1.0.0-alpha", True),
+        ("1.0.0-alpha.beta", True),
+        ("1.0.0-rc.1", True),
+        ("1.0.0-beta.11", True),
+        ("1.0.0-beta.2", True),
+        ("1.0.0-beta", True),
+        ("1.0.0.2", False),
+        ("1.0.0.0rc2", False),
+        ("n.a.n", False),
+        ("hot-fix-666", False),
+    ],
+)
+def test_is_semver(mocker, version, result):
+    # The semver library is responsible for testing all variants, so this
+    # test simply passes some examples and checks that semver.parse is called;
+    # See also https://github.com/k-bx/python-semver/blob/master/test_semver.py
+    parser = mocker.spy(semver.VersionInfo, name="parse")
+    assert is_semver(version) == result
+    assert parser.call_count == 1
+
+
+@pytest.mark.parametrize(
+    "unsorted, sorted_",
+    [
+        (random.sample(SORTED, k=len(SORTED)), SORTED),
+        (["1.0.3", "1.0.2", "1.0.1"], ["1.0.1", "1.0.2", "1.0.3"]),
+        (
+            ["1.0.3", "1.0.2", "1.0.1", "n.a.n", "hot-fix-666"],
+            ["1.0.1", "1.0.2", "1.0.3"],
+        ),
+        (["10.0.3", "1.0.3", "n.a.n", "hot-fix-666"], ["1.0.3", "10.0.3"]),
+    ],
+)
+def test_sem_ver_sorted(mocker, unsorted, sorted_):
+    parser = mocker.spy(semver.VersionInfo, name="parse")
+    assert sorted_semver(unsorted) == sorted_
+    # parse is called to (a) check is_semver and (b) instantiate semver.VersionInfo for sort key
+    assert parser.call_count == (len(unsorted) + len(sorted_))
+    # test the reverse order
+    parser.reset_mock()
+    assert sorted_semver(unsorted, reverse=True) == list(reversed(sorted_))
+    assert parser.call_count == (len(unsorted) + len(sorted_))