shard-ameba/spec/ameba/rule/lint/empty_expression_spec.cr

require "../../../spec_helper"

module Ameba
  subject = Rule::Lint::EmptyExpression.new

  private def it_detects_empty_expression(code, *, file = __FILE__, line = __LINE__)
    it %(detects empty expression "#{code}"), file, line do
      s = Source.new code
      rule = Rule::Lint::EmptyExpression.new
      rule.catch(s).should_not be_valid, file: file, line: line
    end
  end

  describe Rule::Lint::EmptyExpression do
    it "passes if there is no empty expression" do
      s = Source.new <<-CRYSTAL
        def method()
        end

        method()
        method(1, 2, 3)
        method(nil)

        a = nil
        a = ""
        a = 0

        nil
        :any.nil?

        begin "" end
        [nil] << nil
        CRYSTAL
      subject.catch(s).should be_valid
    end

    it_detects_empty_expression %(())
    it_detects_empty_expression %(((())))
    it_detects_empty_expression %(a = ())
    it_detects_empty_expression %((();()))
    it_detects_empty_expression %(if (); end)
    it_detects_empty_expression %(
      if foo
        1
      elsif ()
        2
      end
    )
    it_detects_empty_expression %(
      case foo
      when :foo then ()
      end
    )
    it_detects_empty_expression %(
      case foo
      when :foo then 1
      else
        ()
      end
    )
    it_detects_empty_expression %(
      case foo
      when () then 1
      end
    )
    it_detects_empty_expression %(
      def method
        a = 1
        ()
      end
    )
    it_detects_empty_expression %(
      def method
      rescue
        ()
      end
    )
    it_detects_empty_expression %(
      def method
        begin
        end
      end
    )
    it_detects_empty_expression %(
      begin; end
    )
    it_detects_empty_expression %(
      begin
        nil
      end
    )
    it_detects_empty_expression %(
      begin
        ()
      end
    )

    it "does not report empty expression in macro" do
      s = Source.new %q(
        module MyModule
          macro conditional_error_for_inline_callbacks
            \{%
              raise ""
            %}
          end

          macro before_save(x = nil)
          end
        end
      )
      subject.catch(s).should be_valid
    end
  end
end