Testing GraphQL with Ruby

This will be a rapid and simple article about how to test your GraphQL code in a Rails app with RSpec.

When it comes to Rails and GraphQL, one question that you could ask yourself is. How can I test my queries or mutations?

Should I send an HTTP request? It seems not necessary to do that; what you want is to test the logic of my GraphQL queries or mutations.

Do not worry. You don't have to.

How to test

Let's say you have a simple Schema with a Type called TestableType and a query that resolves testable, which has only a field called tested.

class TheSchema < GraphQL::Schema

  class TestableType < GraphQL::Schema::Object
    field :tested, String
  end

  class Query < GraphQL::Schema::Object
    field :testable, [TestableType], null: true

    def testable
      { name: "You can test me" }
    end
  end

  query(Query)
end

To use graphql, you do not need any framework. You can define everything in the same file.

Now, for testing, we need to use the execute method of the schema. And the string of graphql query that I want to execute.

With what we did earlier, it would look like this if we use minitest.

class TestMeme < Minitest::Test 
  def setup
    @query = <<-GQL
      {
        testable {
          name
        }
      }
    GQL
  end

  def test_that_kitty_can_eat
    assert_equal TamereSchema.execute(@query).to_h.dig('data','testable'), {"name"=>"Pogo Stick"}
  end
end

Conclusion

Now you know how to test your graphql queries without making HTTP requests.

I hope this post helped you to understand more about Ruby and GraphQL. When I began to use GraphQL with Ruby, this was one of the first questions I asked myself.

Here is a gist if you want to see it in action in a Ruby file: https://gist.github.com/Lucas-Barret/b3db09d231165703e5f31ba52487ec60