Use Rspec syntax instead of Test::Unit in ActionDispatch::Request spec.

spec/lib/action_dispatch/request_spec.rb

@@ -1,18 +1,25 @@
+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe ActionDispatch::Request do
   it "strips nils from arrays" do
-    assert_parses({ "key" => ["value"] }, 'key[]=value&key[]')
-    assert_parses({ "key1" => { "key2" => ["value"] } }, 'key1[key2][]=value&key1[key2][]')
+    expect(parse_query_parameters('key[]=value&key[]')).to eq({ "key" => ["value"] })
+  end
+
+  it "strips nils from nested arrays" do
+    expect(
+      parse_query_parameters('key1[key2][]=value&key1[key2][]')
+    ).to eq({ "key1" => { "key2" => ["value"] } })
   end
 
   it "doesn't convert an empty array to nil" do
-    assert_parses({ "key" => [] }, 'key[]')
+    expect(parse_query_parameters('key[]')).to eq({ "key" => [] })
   end
 
   private
 
-  def assert_parses(expected, actual)
-    assert_equal expected, ActionDispatch::Request.new('QUERY_STRING' => actual).query_parameters
+  def parse_query_parameters(query_parameters)
+    ActionDispatch::Request.new("QUERY_STRING" => query_parameters).query_parameters
   end
 end