宏内部使用ExUnit.Assertions

Question

我为测试用例编写了一个小宏。

    defmodule ControllerTest do
      @required [:phone, :country]
      defmacro create(fields) do
        quote do
          without = length(unquote(@required) -- unquote(field)
          if without != 0 do
            Enum.map(unquote(@required), fn(field) ->
              member = Enum.member?(unquote(fields), field)
              if member == false do
                expected_error = String.to_atom(Atom.to_string(field) <> " " <> "can't be blank")
                expected = {:error, expected_error}
               assert expected == {:error, expected_error} 
              end
            end)
          else
            expect = {:success, "Record created"}
            assert expect == {:success, "Record created"}
          end
        end
      end
     end

它在没有断言的情况下工作良好。但是，当我尝试使用assert时，它说assert是未定义的。我已经在模块中尝试了import ExUnit.Assertions，但是仍然没有定义相同的assert。

在宏中使用断言可能的解决方案是什么？

谢谢

Answer 1

在使用import之前，需要在quote中添加assert。在quote之前添加它不会使assert在quote中可用。

defmacro create(fields) do
  quote do
    import ExUnit.Assertions
    without = ...
    ...
  end
end

此外，您的Enum.map也可以简化如下：

for field <- unquote(@required), field not in unquote(fields) do
  expected_error = String.to_atom(Atom.to_string(field) <> " " <> "can't be blank")
  expected = {:error, expected_error}
  assert expected == {:error, expected_error} 
end