vpython: Version parser from PEP440.

vpython/python/version_test.go

 // Copyright 2017 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package python
 
 import (
         "fmt"
         "sort"
         "testing"
@@ skipping 10 matching lines @@
         t.Parallel()
 
         successes := []struct {
                 input string
                 v     Version
         }{
                 {"", Version{}},
                 {"2", Version{2, 0, 0}},
                 {"2.7", Version{2, 7, 0}},
                 {"2.7.12", Version{2, 7, 12}},
+                {"2.7.12+", Version{2, 7, 12}},
+                {"2.7.12+local version string", Version{2, 7, 12}},
+                {"1.4rc1", Version{1, 4, 0}},
+                {"2.7a3", Version{2, 7, 0}},
+                {"1.0b2.post345.dev456", Version{1, 0, 0}},
+                {"1.0+abc.7", Version{1, 0, 0}},
+                {"1.0.dev4", Version{1, 0, 0}},
+                {"1.0.post4", Version{1, 0, 0}},
+                {"2!1.0", Version{1, 0, 0}},
                 {"1000.0.1", Version{1000, 0, 1}},
         }
 
         failures := []struct {
                 input string
                 err   string
         }{
-                {"a", "invalid number value"},
-                {"1.2.3.4", "unsupported number of parts"},
-                {"1.-2.1337", "must not be negative"},
+                {"a", "non-canonical Python version string"},
                 {"0.1.2", "version is incomplete"},
-                {"1.1.X", "invalid patch value"},
-                {"1.Y.1", "invalid minor value"},
-                {"Y.1.1", "invalid major value"},
+                {"1.1.X", "non-canonical Python version string"},
         }
 
         Convey(`Testing ParseVersion`, t, func() {
                 for _, tc := range successes {
                         Convey(fmt.Sprintf(`Success: %q`, tc.input), func() {
                                 v, err := ParseVersion(tc.input)
                                 So(err, ShouldBeNil)
                                 So(v, ShouldResemble, tc.v)
                         })
                 }
@@ skipping 121 matching lines @@
                         So(cp, ShouldResemble, s)
                 })
         })
 }
 
 type versionSlice []Version
 
 func (s versionSlice) Len() int           { return len(s) }
 func (s versionSlice) Less(i, j int) bool { return s[i].Less(&s[j]) }
 func (s versionSlice) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }