Use http 4.x for ruby 2.4 and 2.3

Author: mgrunberg

down.gemspec

@@ -20,7 +20,11 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "minitest", "~> 5.8"
   spec.add_development_dependency "mocha", "~> 1.5"
   spec.add_development_dependency "rake"
-  spec.add_development_dependency "http", "~> 5.0"
+  if RUBY_VERSION >= "2.5"
+    spec.add_development_dependency "http", "~> 5.0"
+  else
+    spec.add_development_dependency "http", "~> 4.3"
+  end
   spec.add_development_dependency "posix-spawn" unless RUBY_ENGINE == "jruby"
   spec.add_development_dependency "http_parser.rb"
   spec.add_development_dependency "docker-api"

test/support/warnings.rb

@@ -2,4 +2,9 @@
   require "warning"
 
   Warning.process('', /instance variable @\w+ not initialized/ => :raise)
+
+  # Starting on ruby 2.5 we use http.rb 5.0. That version don't have http-parser has a dependency
+  if RUBY_VERSION < "2.5"
+    Warning.ignore(/interpreted as argument prefix/, Gem::Specification.find_by_name("http-parser").load_paths.first)
+  end
 end