More explicit error handling

Author: danschultzer

CHANGELOG.md

@@ -1,3 +1,7 @@
+## v0.1.2 (TBA)
+
+- Better formatting of errors
+
 ## v0.1.1 (2022-09-11)
 
 - `TestServer.url/2` no longer autostarts the test server

lib/test_server.ex

@@ -87,9 +87,9 @@ defmodule TestServer do
 
       routes ->
         raise """
-          The test ended before the following #{inspect(__MODULE__)} route(s) received a request:
+        The test ended before the following #{inspect(Instance)} route(s) received a request:
 
-          #{Instance.format_routes(routes)}
+        #{Instance.format_routes(routes)}
         """
     end
   end

lib/test_server/instance.ex

@@ -44,6 +44,7 @@ defmodule TestServer.Instance do
 
   @spec format_routes([map()]) :: binary()
   def format_routes([]), do: "None"
+
   def format_routes(routes) do
     routes
     |> Enum.with_index()
@@ -55,15 +56,16 @@ defmodule TestServer.Instance do
     end)
   end
 
-  @spec report_error(pid(), binary()) :: :ok
-  def report_error(instance, message) do
+  @spec report_error(pid(), {struct(), list()}) :: :ok
+  def report_error(instance, {exception, stacktrace}) do
     options = get_options(instance)
     caller = Keyword.fetch!(options, :caller)
 
-    unless Keyword.get(options, :suppress_warning, false), do: IO.warn(message)
+    unless Keyword.get(options, :suppress_warning, false),
+      do: IO.warn(Exception.format(:error, exception, stacktrace))
 
     ExUnit.OnExitHandler.add(caller, make_ref(), fn ->
-      raise message
+      reraise exception, stacktrace
     end)
 
     :ok

lib/test_server/plug_cowboy.ex

@@ -116,36 +116,24 @@ defmodule TestServer.Plug.Cowboy do
           resp_error(
             conn,
             instance,
-            """
-            Unexpected #{conn.method} request received at #{conn.request_path}.
+            {RuntimeError.exception("""
+             Unexpected #{conn.method} request received at #{conn.request_path}.
 
-            Active routes for request:
+             Active routes for request:
 
-            #{Instance.format_routes(Instance.active_routes(instance))}
-            """
+             #{Instance.format_routes(Instance.active_routes(instance))}
+             """), []}
           )
 
         {:error, {error, stacktrace}} ->
           resp_error(conn, instance, {error, stacktrace})
       end
     end
 
-    defp resp_error(conn, instance, {error, stacktrace}) do
-      resp_error(
-        conn,
-        instance,
-        """
-        #{inspect error}
+    defp resp_error(conn, instance, {exception, stacktrace}) do
+      Instance.report_error(instance, {exception, stacktrace})
 
-        #{Exception.format_stacktrace(stacktrace)}
-        """
-      )
-    end
-
-    defp resp_error(conn, instance, message) do
-      Instance.report_error(instance, message)
-
-      Conn.send_resp(conn, 500, to_string(message))
+      Conn.send_resp(conn, 500, Exception.format(:error, exception, stacktrace))
     end
   end
 end

test/test_server_test.exs

@@ -163,7 +163,7 @@ defmodule TestServerTest do
       end
 
       assert capture_io(fn -> ExUnit.run() end) =~
-               "The test ended before the following TestServer route(s) received a request"
+               "The test ended before the following TestServer.Instance route(s) received a request"
     end
 
     test "with callback plug" do
@@ -177,6 +177,23 @@ defmodule TestServerTest do
       assert request(TestServer.url("/")) == {:ok, to_string(MyPlug)}
     end
 
+    test "with callback function raising exception" do
+      defmodule ToFunctionRaiseTest do
+        use ExUnit.Case
+
+        test "fails" do
+          {:ok, _instance} = TestServer.start(suppress_warning: true)
+
+          assert :ok = TestServer.add("/", to: fn _conn -> raise "boom" end)
+          assert {:ok, _} = unquote(__MODULE__).request(TestServer.url("/"))
+        end
+      end
+
+      assert io = capture_io(fn -> ExUnit.run() end)
+      assert io =~ "(RuntimeError) boom"
+      assert io =~ "anonymous fn/1 in TestServerTest.ToFunctionRaiseTest"
+    end
+
     test "with callback function" do
       assert :ok =
                TestServer.add("/",