Workaround for missing test/unit/assertions when running specs

Now most of the tests pass.

Submissions fail with the message "Lua redis() command arguments must be
strings or integers" because of incompatible qless and redis versions
(seomoz/qless-core#64).

spec/test/unit/assertions.rb

@@ -0,0 +1,16 @@
+# This files provides test/unit/assertions for rspec-rails <3.2.0 by
+# aliasing Test::Unit::Assertions to MiniTest::Assertions.
+# When rspec-rails is updated to 3.2.0+ this file should be removed.
+#
+# test/unit/assertions was removed from ruby-core in 2.2.0 (https://bugs.ruby-lang.org/issues/9711).
+# rspec-rails <3.2.0 doesn't handle the removal on rails 4.0.x (fixed in https://github.com/rspec/rspec-rails/pull/1264).
+require 'active_support/deprecation'
+ActiveSupport::Deprecation.warn 'This file should be removed when rspec-rails is updated to 3.2.0+'
+
+require 'minitest/unit'
+
+module Test
+  module Unit
+    Assertions = MiniTest::Assertions
+  end
+end