diff --git a/.travis.yml b/.travis.yml
index aedaed80f..d99dcc4dc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ rvm:
   - 2.0.0
   - 2.1
   - 2.2
+  - 2.3.1
 
 matrix:
   include:
diff --git a/Gemfile b/Gemfile
index 3be9c3cd8..bcaad77bc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,10 @@
 source "https://rubygems.org"
 gemspec
+
+if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.2.2")
+  gem 'rack', '< 2.0'
+end
+
+if Gem::Version.new(RUBY_VERSION) < Gem::Version.new("2.0")
+  gem 'json', '< 2.0'
+end
diff --git a/gemfiles/Gemfile-1.9 b/gemfiles/Gemfile-1.9
index a51700c42..927a4d9eb 100644
--- a/gemfiles/Gemfile-1.9
+++ b/gemfiles/Gemfile-1.9
@@ -1,3 +1,5 @@
 source "https://rubygems.org"
 gemspec path: '..'
 gem 'sass', '< 3.4'
+gem 'rack', '< 2.0'
+gem 'json', '< 2.0'
diff --git a/lib/sprockets/resolve.rb b/lib/sprockets/resolve.rb
index d6cae616c..9ae14fb3e 100644
--- a/lib/sprockets/resolve.rb
+++ b/lib/sprockets/resolve.rb
@@ -178,6 +178,7 @@ def dirname_matches(dirname, basename)
         candidates = []
         entries = self.entries(dirname)
         entries.each do |entry|
+          next unless File.basename(entry).start_with?(basename)
           name, type, _, _ = parse_path_extnames(entry)
           if basename == name
             candidates << [File.join(dirname, entry), type]