Update specs for assert_nil

Author: rmosolgo

spec/graphql/schema_spec.rb

@@ -47,6 +47,7 @@ class CustomSubscriptions < GraphQL::Subscriptions::ActionCableSubscriptions
         extra_types ExtraType
         query_analyzer Object.new
         multiplex_analyzer Object.new
+        validate_timeout 100
         rescue_from(StandardError) { }
         use GraphQL::Backtrace
         use GraphQL::Subscriptions::ActionCableSubscriptions, action_cable: nil, action_cable_coder: JSON

spec/integration/rails/graphql/query/variables_spec.rb

@@ -230,7 +230,11 @@ class << self
 
       def assert_has_key_with_value(hash, key, has_key, value)
         assert_equal(has_key, hash.key?(key))
-        assert_equal(value, hash[key])
+        if value.nil?
+          assert_nil hash[key]
+        else
+          assert_equal(value, hash[key])
+        end
       end
 
       it "preserves explicit null" do