fix: define replaced Elixir module macros using defmacro (#104)

Author: yastanotheruser

lib/mimic/module.ex

@@ -117,8 +117,9 @@ defmodule Mimic.Module do
     mimic_info = module_mimic_info(opts)
     mimic_behaviours = generate_mimic_behaviours(module)
     mimic_functions = generate_mimic_functions(module)
+    mimic_macros = generate_mimic_macros(module)
     mimic_struct = generate_mimic_struct(module)
-    quoted = [mimic_info, mimic_struct | mimic_behaviours ++ mimic_functions]
+    quoted = [mimic_info, mimic_struct | mimic_behaviours ++ mimic_functions ++ mimic_macros]
     Module.create(module, quoted, Macro.Env.location(__ENV__))
     module
   end
@@ -175,7 +176,14 @@ defmodule Mimic.Module do
   defp generate_mimic_functions(module) do
     internal_functions = [__info__: 1, module_info: 0, module_info: 1]
 
-    for {fn_name, arity} <- module.module_info(:exports),
+    functions =
+      if function_exported?(module, :__info__, 1) do
+        module.__info__(:functions)
+      else
+        module.module_info(:exports)
+      end
+
+    for {fn_name, arity} <- functions,
         {fn_name, arity} not in internal_functions do
       args = Macro.generate_arguments(arity, module)
 
@@ -187,6 +195,26 @@ defmodule Mimic.Module do
     end
   end
 
+  defp generate_mimic_macros(module) do
+    macros =
+      if function_exported?(module, :__info__, 1) do
+        module.__info__(:macros)
+      else
+        []
+      end
+
+    for {macro_name, arity} <- macros do
+      args = Macro.generate_arguments(arity, module)
+      macro_fun = String.to_existing_atom("MACRO-#{macro_name}")
+
+      quote do
+        defmacro unquote(macro_name)(unquote_splicing(args)) do
+          Server.apply(__MODULE__, unquote(macro_fun), [__CALLER__ | unquote(args)])
+        end
+      end
+    end
+  end
+
   defp generate_mimic_behaviours(module) do
     module.module_info(:attributes)
     |> Keyword.get_values(:behaviour)

test/mimic_test.exs

@@ -489,6 +489,17 @@ defmodule Mimic.Test do
         expect(Calculator, :add, 0, fn x, y -> x + y end)
       end
     end
+
+    test "macros" do
+      expect(Calculator, :add, fn x, _y -> x + 2 end)
+
+      quote do
+        require Calculator
+
+        assert Calculator.add(4, 2) == Calculator.add_macro(4, 2)
+      end
+      |> Code.eval_quoted()
+    end
   end
 
   describe "expect/4 global mode" do

test/support/test_modules.ex

@@ -1,6 +1,8 @@
 defmodule AddAdapter do
   @moduledoc false
   @callback add(number(), number()) :: number()
+  @macrocallback add_macro(Macro.t(), Macro.t()) :: Macro.t()
+  @optional_callbacks add_macro: 2
 end
 
 defmodule MultAdapter do
@@ -13,6 +15,7 @@ defmodule Calculator do
   @behaviour AddAdapter
   @behaviour MultAdapter
   def add(x, y), do: x + y
+  defmacro add_macro(x, y), do: {:+, [], [x, y]}
   def mult(x, y), do: x * y
 end