Keep track of previous versions of keys

tests/test_s3/test_s3_utils.py

@@ -1,5 +1,5 @@
 from sure import expect
-from moto.s3.utils import bucket_name_from_url
+from moto.s3.utils import bucket_name_from_url, _VersionedKeyStore
 
 
 def test_base_url():
@@ -12,3 +12,40 @@ def test_localhost_bucket():
 
 def test_localhost_without_bucket():
     expect(bucket_name_from_url('https://www.localhost:5000/def')).should.equal(None)
+
+def test_versioned_key_store():
+    d = _VersionedKeyStore()
+
+    d.should.have.length_of(0)
+
+    d['key'] = [1]
+
+    d.should.have.length_of(1)
+
+    d['key'] = 2
+    d.should.have.length_of(1)
+
+    d.should.have.key('key').being.equal(2)
+
+    d.get.when.called_with('key').should.return_value(2)
+    d.get.when.called_with('badkey').should.return_value(None)
+    d.get.when.called_with('badkey', 'HELLO').should.return_value('HELLO')
+
+    # Tests key[
+    d.shouldnt.have.key('badkey')
+    d.__getitem__.when.called_with('badkey').should.throw(KeyError)
+
+    d.getlist('key').should.have.length_of(2)
+    d.getlist('key').should.be.equal([[1], 2])
+    d.getlist('badkey').should.be.none
+
+    d.setlist('key', 1)
+    d.getlist('key').should.be.equal([1])
+
+    d.setlist('key', (1, 2))
+    d.getlist('key').shouldnt.be.equal((1, 2))
+    d.getlist('key').should.be.equal([1, 2])
+
+    d.setlist('key', [[1], [2]])
+    d['key'].should.have.length_of(1)
+    d.getlist('key').should.be.equal([[1], [2]])