diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f69ff81..aa020ef 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-18.04
     strategy:
       matrix:
-        ruby: [2.4, 2.5, 2.6, 2.7]
+        ruby: [2.4, 2.5, 2.6, 2.7, 3.0]
 
     steps:
     - uses: actions/checkout@master
diff --git a/lib/fast_jsonapi/helpers.rb b/lib/fast_jsonapi/helpers.rb
index 600dad7..09a48fa 100644
--- a/lib/fast_jsonapi/helpers.rb
+++ b/lib/fast_jsonapi/helpers.rb
@@ -10,7 +10,7 @@ module FastJsonapi
       # from explictly defined procs/lambdas, so we can't deduce the number of
       # parameters from the array length. Instead, look for an unnamed
       # parameter in the first position just pass the record as the receiver obj.
-      if proc.parameters.length > 0 && proc.parameters.first[1].nil?
+      if proc.parameters.positive? && !proc.parameters.empty?
         proc.call(params.first)
       else
         proc.call(*params.take(proc.parameters.length))
diff --git a/lib/fast_jsonapi/relationship.rb b/lib/fast_jsonapi/relationship.rb
index 31e804e..cc26d70 100644
--- a/lib/fast_jsonapi/relationship.rb
+++ b/lib/fast_jsonapi/relationship.rb
@@ -12,12 +12,7 @@ module FastJsonapi
       object_block:,
       serializer:,
       relationship_type:,
-      cached: false,
-      polymorphic:,
-      conditional_proc:,
-      transform_method:,
-      links:,
-      meta:,
+      polymorphic:, conditional_proc:, transform_method:, links:, meta:, cached: false,
       lazy_load_data: false
     )
       @owner = owner
diff --git a/lib/jsonapi/serializer/errors.rb b/lib/jsonapi/serializer/errors.rb
index f5372a8..7272eec 100644
--- a/lib/jsonapi/serializer/errors.rb
+++ b/lib/jsonapi/serializer/errors.rb
@@ -3,6 +3,7 @@
 module JSONAPI
   module Serializer
     class Error < StandardError; end
+
     class UnsupportedIncludeError < Error
       attr_reader :include_item, :klass
 
diff --git a/spec/fixtures/movie.rb b/spec/fixtures/movie.rb
index 101616f..a8a086d 100644
--- a/spec/fixtures/movie.rb
+++ b/spec/fixtures/movie.rb
@@ -50,7 +50,7 @@ class MovieSerializer
 
   attribute :released_in_year, &:year
   attributes :name
-  attribute :release_year do |object, params|
+  attribute :release_year do |object, _params|
     object.year
   end