[PyPI] Fixes Python versions order by using proper Semver comparison (#6000)

* [PyPI] Fixes Python versions order by using proper Semver comparison

* [PyPI] Adds a proper specification file for Python versions service

Co-authored-by: repo-ranger[bot] <39074581+repo-ranger[bot]@users.noreply.github.com>

services/pypi/pypi-python-versions.service.js

 'use strict'
 
+const semver = require('semver')
 const PypiBase = require('./pypi-base')
 const { parseClassifiers } = require('./pypi-helpers')
 
@@ -30,7 +31,11 @@ module.exports = class PypiPythonVersions extends PypiBase {
     })
     if (versionSet.size) {
       return {
-        message: Array.from(versionSet).sort().join(' | '),
+        message: Array.from(versionSet)
+          .sort((v1, v2) =>
+            semver.compare(semver.coerce(v1), semver.coerce(v2))
+          )
+          .join(' | '),
         color: 'blue',
       }
     } else {

services/pypi/pypi-python-versions.spec.js

+'use strict'
+
+const { test, given } = require('sazerac')
+const { render } = require('./pypi-python-versions.service')
+
+describe('PyPI Python Version', function () {
+  test(render, function () {
+    // Major versions are hidden if minor are present.
+    given({ versions: ['3', '3.4', '3.5', '3.6', '2', '2.7'] }).expect({
+      message: '2.7 | 3.4 | 3.5 | 3.6',
+      color: 'blue',
+    })
+
+    // Major versions are shown when minor are missing.
+    given({ versions: ['2', '3'] }).expect({
+      message: '2 | 3',
+      color: 'blue',
+    })
+
+    // Versions are properly sorted according to their Semver segments.
+    given({ versions: ['3.10', '3.9', '3.8', '3.7', '3.6'] }).expect({
+      message: '3.6 | 3.7 | 3.8 | 3.9 | 3.10',
+      color: 'blue',
+    })
+
+    // Only "one" version works too.
+    given({ versions: ['3', '3.9'] }).expect({
+      message: '3.9',
+      color: 'blue',
+    })
+
+    // Versions are missing...
+    given({ versions: [] }).expect({
+      message: 'missing',
+      color: 'red',
+    })
+  })
+})