Convert hash keys to camel case deeply

gistfile1.rb

require "minitest/autorun"
require "json"
require "active_support/inflector"

def to_camel(data)
  # Do nothing when data is neither Hash or Array.
  # This is the guard for array data which mixes non different class.
  return data unless data.respond_to?(:inject)

  data.inject({}) do |h,(k,v)|
    if v.kind_of? Hash
      v = to_camel(v)
    end

    if v.kind_of? Array
      v = v.map {|a| to_camel(a)}
    end

    h[k.camelize(:lower)] = v; h
  end
end

describe "to_camel" do
  let(:flat_hash) {
    {
      "my_name" => "Kim Hirokuni",
      "age" => 31
    }
  }

  let(:nested_hash) {
    {
      "my_name" => "Kim Hirokuni",
      "physical_feature" => {
        "color_of_eye" => "black"
      },
      "job_history" => {
        "kvh" => {
          "job_title" => "enginner"
        }
      }
    }
  }

  let(:nested_array) {
    {
      "my_name" => "Kim Hirokuni",
      "pets_history" => [
        {"pet_name" => "eru"},
        {"pet_name" => "leo"},
        "string"
      ]
    }
  }

  let(:string) {
    "string"
  }


  it "converts flat hash" do
    assert_equal({"myName" => "Kim Hirokuni", "age" => 31}, to_camel(flat_hash))
  end

  it "converts nested hash" do
    assert_equal(
      {"myName" => "Kim Hirokuni", "physicalFeature" => {"colorOfEye" => "black"}, "jobHistory" => {"kvh" => {"jobTitle"=> "enginner"}}},
      to_camel(nested_hash)
    )
  end

  it "converts nested hash in array" do
    assert_equal({"myName" => "Kim Hirokuni", "petsHistory" => [{"petName" => "eru"}, {"petName" => "leo"}, "string"]}, to_camel(nested_array))
  end

  it 'does nothing when passing object that doesn not implement #inject' do
    assert_equal("string", to_camel(string))
  end

end