From 40fb0ee57bd94ddb4e4eff6a04b2bb275e36b02f Mon Sep 17 00:00:00 2001
From: Ian Cordasco <graffatcolmingov@gmail.com>
Date: Sat, 26 Jul 2014 11:26:55 -0500
Subject: [PATCH] Add merge_paths function and tests for it

---
 rfc3986/misc.py    | 11 +++++++++++
 tests/test_misc.py | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 tests/test_misc.py

diff --git a/rfc3986/misc.py b/rfc3986/misc.py
index b89269b..7cc02a9 100644
--- a/rfc3986/misc.py
+++ b/rfc3986/misc.py
@@ -197,3 +197,14 @@ hier_part = '(//%s%s|%s|%s|%s)' % (
 ABSOLUTE_URI_MATCHER = re.compile('^%s:%s(\?%s)$' % (
     component_pattern_dict['scheme'], hier_part, QUERY_MATCHER.pattern
     ))
+
+
+# Path merger as defined in http://tools.ietf.org/html/rfc3986#section-5.2.3
+def merge_paths(base_uri, relative_path):
+    """Merge a base URI's path with a relative URI's path."""
+    if base_uri.path is None and base_uri.authority is not None:
+        return '/' + relative_path
+    else:
+        path = base_uri.path or ''
+        index = path.rfind('/')
+        return path[:index] + '/' + relative_path
diff --git a/tests/test_misc.py b/tests/test_misc.py
new file mode 100644
index 0000000..eced326
--- /dev/null
+++ b/tests/test_misc.py
@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+from rfc3986.uri import URIReference
+from rfc3986.misc import merge_paths
+
+
+def test_merge_paths_with_base_path_without_base_authority():
+    """Demonstrate merging with a base URI without an authority."""
+    base = URIReference(scheme=None,
+                        authority=None,
+                        path='/foo/bar/bogus',
+                        query=None,
+                        fragment=None)
+    expected = '/foo/bar/relative'
+    assert merge_paths(base, 'relative') == expected
+
+
+def test_merge_paths_with_base_authority_and_path():
+    """Demonstrate merging with a base URI with an authority and path."""
+    base = URIReference(scheme=None,
+                        authority='authority',
+                        path='/foo/bar/bogus',
+                        query=None,
+                        fragment=None)
+    expected = '/foo/bar/relative'
+    assert merge_paths(base, 'relative') == expected
+
+
+def test_merge_paths_without_base_authority_or_path():
+    """Demonstrate merging with a base URI without an authority or path."""
+    base = URIReference(scheme=None,
+                        authority=None,
+                        path=None,
+                        query=None,
+                        fragment=None)
+    expected = '/relative'
+    assert merge_paths(base, 'relative') == expected
+
+
+def test_merge_paths_with_base_authority_without_path():
+    """Demonstrate merging with a base URI without an authority or path."""
+    base = URIReference(scheme=None,
+                        authority='authority',
+                        path=None,
+                        query=None,
+                        fragment=None)
+    expected = '/relative'
+    assert merge_paths(base, 'relative') == expected