Add more tests for Utils.encode_query_string.

These tests, which follow the yard-doc examples, exercise the
new ParamsArray behavior.

lib/restclient/utils.rb

@@ -154,7 +154,7 @@ module RestClient
     #   => 'foo[string]=&foo[empty]'
     #
     # @example Multiple fields with the same name using ParamsArray
-    #   >> encode_query_string(RestClient::ParamsArray.new([[:foo, 1], [:foo, 2], [:foo, 3]])
+    #   >> encode_query_string(RestClient::ParamsArray.new([[:foo, 1], [:foo, 2], [:foo, 3]]))
     #   => 'foo=1&foo=2&foo=3'
     #
     # @example Nested ParamsArray

spec/unit/utils_spec.rb

@@ -118,5 +118,30 @@ describe RestClient::Utils do
         RestClient::Utils.encode_query_string(input).should eq expected
       end
     end
+
+    it 'handles deep nesting' do
+      {
+        {coords: [{x: 1, y: 0}, {x: 2}, {x: 3}]} => 'coords[][x]=1&coords[][y]=0&coords[][x]=2&coords[][x]=3',
+      }.each_pair do |input, expected|
+        RestClient::Utils.encode_query_string(input).should eq expected
+      end
+    end
+
+    it 'handles multiple fields with the same name using ParamsArray' do
+      {
+        RestClient::ParamsArray.new([[:foo, 1], [:foo, 2], [:foo, 3]]) => 'foo=1&foo=2&foo=3',
+      }.each_pair do |input, expected|
+        RestClient::Utils.encode_query_string(input).should eq expected
+      end
+    end
+
+    it 'handles nested ParamsArrays' do
+      {
+        {foo: RestClient::ParamsArray.new([[:a, 1], [:a, 2]])} => 'foo[a]=1&foo[a]=2',
+        RestClient::ParamsArray.new([[:foo, {a: 1}], [:foo, {a: 2}]]) => 'foo[a]=1&foo[a]=2',
+      }.each_pair do |input, expected|
+        RestClient::Utils.encode_query_string(input).should eq expected
+      end
+    end
   end
 end