Add support for NPM-style version ranges.

The code follows closely the specification available at
https://docs.npmjs.com/misc/semver.html.

Despite similarities, the matching logic is fully separate from the
`native` code, since both might evolve at their own scales.

3 files changed, 105 insertions, 3 deletions

diff --git a/tests/django_test_app/models.py b/tests/django_test_app/models.py
index 3a43cfc..5f790b4 100644
--- a/tests/django_test_app/models.py
+++ b/tests/django_test_app/models.py
@@ -14,6 +14,7 @@ if django_loaded:
     class VersionModel(models.Model):
         version = semver_fields.VersionField(verbose_name='my version')
         spec = semver_fields.SpecField(verbose_name='my spec')
+        npm_spec = semver_fields.SpecField(syntax='npm', blank=True, verbose_name='npm spec')
 
     class PartialVersionModel(models.Model):
         partial = semver_fields.VersionField(partial=True, verbose_name='partial version')
diff --git a/tests/test_django.py b/tests/test_django.py
index b5c4a9c..5fff8a9 100644
--- a/tests/test_django.py
+++ b/tests/test_django.py
@@ -4,7 +4,7 @@
 
 import unittest
 
-from semantic_version import Version, NativeSpec
+from semantic_version import Version, SimpleSpec, NpmSpec
 
 from .setup_django import django_loaded
 
@@ -64,25 +64,29 @@ class DjangoFieldTestCase(unittest.TestCase):
         obj = models.VersionModel(
             version=Version('0.1.1'),
             spec=SimpleSpec('==0.1.1,!=0.1.1-alpha'),
+            npm_spec=NpmSpec('1.2 - 2.3'),
         )
 
         self.assertEqual(Version('0.1.1'), obj.version)
         self.assertEqual(SimpleSpec('==0.1.1,!=0.1.1-alpha'), obj.spec)
+        self.assertEqual(NpmSpec('1.2 - 2.3'), obj.npm_spec)
 
-        alt_obj = models.VersionModel(version=obj.version, spec=obj.spec)
+        alt_obj = models.VersionModel(version=obj.version, spec=obj.spec, npm_spec=obj.npm_spec)
 
         self.assertEqual(Version('0.1.1'), alt_obj.version)
         self.assertEqual(SimpleSpec('==0.1.1,!=0.1.1-alpha'), alt_obj.spec)
         self.assertEqual(obj.spec, alt_obj.spec)
+        self.assertEqual(obj.npm_spec, alt_obj.npm_spec)
         self.assertEqual(obj.version, alt_obj.version)
 
     def test_version_clean(self):
         """Calling .full_clean() should convert str to Version/Spec objects."""
-        obj = models.VersionModel(version='0.1.1', spec='==0.1.1,!=0.1.1-alpha')
+        obj = models.VersionModel(version='0.1.1', spec='==0.1.1,!=0.1.1-alpha', npm_spec='1.x')
         obj.full_clean()
 
         self.assertEqual(Version('0.1.1'), obj.version)
         self.assertEqual(SimpleSpec('==0.1.1,!=0.1.1-alpha'), obj.spec)
+        self.assertEqual(NpmSpec('1.x'), obj.npm_spec)
 
     def test_version_save(self):
         """Test saving object with a VersionField."""
@@ -166,10 +170,12 @@ class DjangoFieldTestCase(unittest.TestCase):
         o1 = models.VersionModel(
             version=Version('0.1.1'),
             spec=SimpleSpec('==0.1.1,!=0.1.1-alpha'),
+            npm_spec=NpmSpec('1.2 - 2.3'),
         )
         o2 = models.VersionModel(
             version=Version('0.4.3-rc3+build3'),
             spec=SimpleSpec('<=0.1.1-rc2,!=0.1.1-rc1'),
+            npm_spec=NpmSpec('1.2 - 2.3'),
         )
 
         data = serializers.serialize('json', [o1, o2])
@@ -177,8 +183,10 @@ class DjangoFieldTestCase(unittest.TestCase):
         obj1, obj2 = serializers.deserialize('json', data)
         self.assertEqual(o1.version, obj1.object.version)
         self.assertEqual(o1.spec, obj1.object.spec)
+        self.assertEqual(o1.npm_spec, obj1.object.npm_spec)
         self.assertEqual(o2.version, obj2.object.version)
         self.assertEqual(o2.spec, obj2.object.spec)
+        self.assertEqual(o2.npm_spec, obj2.object.npm_spec)
 
     def test_serialization_partial(self):
         o1 = models.PartialVersionModel(
@@ -220,6 +228,11 @@ class FieldMigrationTests(DjangoTestCase):
         expected = {'max_length': 200}
         self.assertEqual(field.deconstruct()[3], expected)
 
+    def test_nondefault_spec_field(self):
+        field = django_fields.SpecField(syntax='npm')
+        expected = {'max_length': 200, 'syntax': 'npm'}
+        self.assertEqual(field.deconstruct()[3], expected)
+
 
 @unittest.skipIf(not django_loaded, "Django not installed")
 class FullMigrateTests(TransactionTestCase):
diff --git a/tests/test_npm.py b/tests/test_npm.py
new file mode 100644
index 0000000..76cb6e2
--- /dev/null
+++ b/tests/test_npm.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (c) The python-semanticversion project
+# This code is distributed under the two-clause BSD License.
+
+"""Test NPM-style specifications."""
+
+import unittest
+
+from semantic_version import base
+
+
+class NpmSpecTests(unittest.TestCase):
+    examples = {
+        # range: [matchings], [failings]
+        '>=1.2.7': (
+            ['1.2.7', '1.2.8', '1.3.9'],
+            ['1.2.6', '1.1.0'],
+        ),
+        '>=1.2.7 <1.3.0': (
+            ['1.2.7', '1.2.8', '1.2.99'],
+            ['1.2.6', '1.3.0', '1.1.0'],
+        ),
+        '1.2.7 || >=1.2.9 <2.0.0': (
+            ['1.2.7', '1.2.9', '1.4.6'],
+            ['1.2.8', '2.0.0'],
+        ),
+        '>1.2.3-alpha.3': (
+            ['1.2.3-alpha.7', '3.4.5'],
+            ['1.2.3-alpha.3', '3.4.5-alpha.9'],
+        ),
+        '>=1.2.3-alpha.3': (
+            ['1.2.3-alpha.3', '1.2.3-alpha.7', '3.4.5'],
+            ['1.2.3-alpha.2', '3.4.5-alpha.9'],
+        ),
+        '1.2.3 - 2.3.4': (
+            ['1.2.3', '1.2.99', '2.2.0', '2.3.4', '2.3.4+b42'],
+            ['1.2.0', '1.2.3-alpha.1', '2.3.5'],
+        ),
+        '~1.2.3-beta.2': (
+            ['1.2.3-beta.2', '1.2.3-beta.4', '1.2.4'],
+            ['1.2.4-beta.2', '1.3.0'],
+        ),
+    }
+
+    def test_spec(self):
+        for spec, lists in self.examples.items():
+            matching, failing = lists
+            for version in matching:
+                with self.subTest(spec=spec, version=version):
+                    self.assertIn(base.Version(version), base.NpmSpec(spec))
+            for version in failing:
+                with self.subTest(spec=spec, version=version):
+                    self.assertNotIn(base.Version(version), base.NpmSpec(spec))
+
+    expansions = {
+        # Hyphen ranges
+        '1.2.3 - 2.3.4': '>=1.2.3 <=2.3.4',
+        '1.2 - 2.3.4': '>=1.2.0 <=2.3.4',
+        '1.2.3 - 2.3': '>=1.2.3 <2.4.0',
+        '1.2.3 - 2': '>=1.2.3 <3',
+
+        # X-Ranges
+        '*': '>=0.0.0',
+        '1.x': '>=1.0.0 <2.0.0',
+        '1.2.x': '>=1.2.0 <1.3.0',
+        '': '*',
+        '1': '1.x.x',
+        '1.x.x': '>=1.0.0 <2.0.0',
+        '1.2': '1.2.x',
+
+        # Tilde ranges
+        '~1.2.3': '>=1.2.3 <1.3.0',
+        '~1.2': '>=1.2.0 <1.3.0',
+        '~1': '>=1.0.0 <2.0.0',
+        '~0.2.3': '>=0.2.3 <0.3.0',
+        '~0.2': '>=0.2.0 <0.3.0',
+        '~0': '>=0.0.0 <1.0.0',
+        '~1.2.3-beta.2': '>=1.2.3-beta.2 <1.3.0',
+    }
+
+    def test_expand(self):
+        for source, expanded in self.expansions.items():
+            with self.subTest(source=source):
+                self.assertEqual(
+                    base.NpmSpec(source).clause,
+                    base.NpmSpec(expanded).clause,
+                )