module ActiveModel::Serializer::Lint::Tests

def assert_instance_of(result, name)
  assert result.instance_of?(name), "#{result} should be an instance of #{name}"
end

def resource
  @resource or fail "'@resource' must be set as the linted object"
end

def test_active_model_errors
  assert_respond_to resource, :errors
end

def test_active_model_errors_human_attribute_name
  assert_respond_to resource.class, :human_attribute_name
  assert_equal(-2, resource.class.method(:human_attribute_name).arity)
end

def test_active_model_errors_lookup_ancestors
  assert_respond_to resource.class, :lookup_ancestors
  assert_equal 0, resource.class.method(:lookup_ancestors).arity
end

def test_as_json
  assert_respond_to resource, :as_json
  resource.as_json
  resource.as_json(nil)
end

def test_cache_key
  assert_respond_to resource, :cache_key
  actual_arity = resource.method(:cache_key).arity
  # using absolute value since arity is:
  #   0 for Rails 4.1+, *timestamp_names
  #  -1 for Rails 4.0, no arguments
  assert_includes [-1, 0], actual_arity, "expected #{actual_arity.inspect} to be 0 or -1"
end

def test_id
  assert_respond_to resource, :id
  assert_equal 0, resource.method(:id).arity
end

def test_model_name
  resource_class = resource.class
  assert_respond_to resource_class, :model_name
  assert_instance_of resource_class.model_name, ActiveModel::Name
end

def test_read_attribute_for_serialization
  assert_respond_to resource, :read_attribute_for_serialization, 'The resource should respond to read_attribute_for_serialization'
  actual_arity = resource.method(:read_attribute_for_serialization).arity
  if defined?(::Rubinius)
    #  1 for def read_attribute_for_serialization(name); end
    # -2 for alias :read_attribute_for_serialization :send for rbx because :shrug:
    assert_includes [1, -2], actual_arity, "expected #{actual_arity.inspect} to be 1 or -2"
  else
    # using absolute value since arity is:
    #  1 for def read_attribute_for_serialization(name); end
    # -1 for alias :read_attribute_for_serialization :send
    assert_includes [1, -1], actual_arity, "expected #{actual_arity.inspect} to be 1 or -1"
  end
end

def test_serializable_hash
  assert_respond_to resource, :serializable_hash, 'The resource should respond to serializable_hash'
  resource.serializable_hash
  resource.serializable_hash(nil)
end

def test_to_json
  assert_respond_to resource, :to_json
  resource.to_json
  resource.to_json(nil)
end

def test_updated_at
  assert_respond_to resource, :updated_at
  actual_arity = resource.method(:updated_at).arity
  assert_equal 0, actual_arity
end