Handle impl function raising by raising in the client process

- Raising in the server would give the wrong behavior

Co-Authored-By: JB Steadman <[email protected]>

lib/protomock.ex

@@ -385,6 +385,7 @@ defmodule ProtoMock do
 
       ref ->
         receive do
+          {^ref, {:protomock_error, e}} -> raise e
           {^ref, response} -> response
         end
     end
@@ -453,7 +454,11 @@ defmodule ProtoMock do
         ref = make_ref()
 
         Task.async(fn ->
-          response = Kernel.apply(impl, args)
+          response = try do
+            Kernel.apply(impl, args)
+          rescue
+            e -> {:protomock_error, e}
+          end
           send(from_pid, {ref, response})
         end)
 

test/protomock_test.exs

@@ -245,6 +245,16 @@ defmodule ProtoMockTest do
     end
   end
 
+  describe "invoke" do
+    test "raises errors that the impl function raises in the client" do
+      protomock =
+        ProtoMock.new()
+        |> ProtoMock.stub(&Calculator.add/3, fn _x, _y -> raise "crash" end)
+
+      assert_raise RuntimeError, "crash", fn -> Calculator.add(protomock, 1, 2) end
+    end
+  end
+
   defp mock_add() do
     mock_add(ProtoMock.new())
   end