support bucket names in url paths in s3bucket_path

tests/test_s3bucket_path/test_s3bucket_path_utils.py

@@ -0,0 +1,14 @@
+from sure import expect
+from moto.s3bucket_path.utils import bucket_name_from_url
+
+
+def test_base_url():
+    expect(bucket_name_from_url('https://s3.amazonaws.com/')).should.equal(None)
+
+
+def test_localhost_bucket():
+    expect(bucket_name_from_url('https://localhost:5000/wfoobar/abc')).should.equal("wfoobar")
+
+
+def test_localhost_without_bucket():
+    expect(bucket_name_from_url('https://www.localhost:5000')).should.equal(None)