Try to preserve consecutive slashes in a relative path.

This is a workaround for a bug of URI#+ that led to failure in
resolving a relative path containing double slash like
"/../http://.../".  GH sparklemotion#304

CHANGELOG.rdoc

@@ -12,6 +12,7 @@
 
 * Bug fix
   * Ensure page URLs with whitespace in them are escaped #313 @pacop.
+  * Added a workaround for a bug of URI#+ that led to failure in resolving a relative path containing double slash like "/../http://.../". #304
 
 === 2.6.0
 

lib/mechanize/http/agent.rb

@@ -660,7 +660,16 @@ def resolve(uri, referer = current_page)
         base = nil
       end
 
-      uri = referer_uri + (base ? base.uri : referer_uri) + uri
+      base = referer_uri + (base ? base.uri : referer_uri)
+
+      # Workaround for URI's bug in that it squashes consecutive
+      # slashes.  See #304.
+      if uri.path.match(%r{\A(.*?/)(?!/\.\.?(?!/))(/.*)\z}i)
+        uri = URI((base + $1).to_s + $2)
+      else
+        uri = base + uri
+      end
+
       # Strip initial "/.." bits from the path
       uri.path.sub!(/^(\/\.\.)+(?=\/)/, '')
     end

test/test_mechanize_http_agent.rb

@@ -697,6 +697,15 @@ def test_resolve_parameters_query_append
     assert_nil params
   end
 
+  def test_resolve_slashes
+    page = Mechanize::Page.new URI('http://example/foo/'), nil, '', 200, @mech
+    uri = '/bar/http://example/test/'
+
+    resolved = @agent.resolve uri, page
+
+    assert_equal 'http://example/bar/http://example/test/', resolved.to_s
+  end
+
   def test_response_authenticate
     @agent.add_auth @uri, 'user', 'password'