From 8e8efd8defa25d864ec034c3fe45a098b9ad733b Mon Sep 17 00:00:00 2001
From: Shashwat Ganesh <shashwatganesh@protonmail.com>
Date: Thu, 4 Jun 2020 22:52:32 +0530
Subject: [PATCH 1/3] Move from System.stacktrace to __STACKTRACE__

---
 lib/execute.ex | 6 +++---
 lib/koans.ex   | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/execute.ex b/lib/execute.ex
index 4ddebae..485e0c5 100644
--- a/lib/execute.ex
+++ b/lib/execute.ex
@@ -38,14 +38,14 @@ defmodule Execute do
 
   defp expand(:ok, _), do: :ok
 
-  defp expand(error, module) do
+  defp expand({:error, stacktrace, exception}, module) do
     {file, line} =
-      System.stacktrace()
+      stacktrace
       |> Enum.drop_while(&(!in_koan?(&1, module)))
       |> List.first()
       |> extract_file_and_line
 
-    %{error: error, file: file, line: line}
+    %{error: exception, file: file, line: line}
   end
 
   defp in_koan?({module, _, _, _}, koan), do: module == koan
diff --git a/lib/koans.ex b/lib/koans.ex
index 31fb9de..5ab03b3 100644
--- a/lib/koans.ex
+++ b/lib/koans.ex
@@ -22,7 +22,7 @@ defmodule Koans do
           unquote(compiled_body)
           :ok
         rescue
-          e -> e
+          e -> {:error, __STACKTRACE__, e}
         end
       end
     end
@@ -39,7 +39,7 @@ defmodule Koans do
           unquote(single_var)
           :ok
         rescue
-          e -> e
+          e -> {:error, __STACKTRACE__, e}
         end
       end
     end
@@ -57,7 +57,7 @@ defmodule Koans do
           unquote(multi_var)
           :ok
         rescue
-          e -> e
+          e -> {:error, __STACKTRACE__, e}
         end
       end
     end

From 0681f5df22a9fb0101dc2dc17b26fd9ee2d1bf8d Mon Sep 17 00:00:00 2001
From: Shashwat Ganesh <shashwatganesh@protonmail.com>
Date: Thu, 4 Jun 2020 22:54:18 +0530
Subject: [PATCH 2/3] Tests should provide valid error parameters

---
 test/display/failure_test.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/display/failure_test.exs b/test/display/failure_test.exs
index bea195e..addce2c 100644
--- a/test/display/failure_test.exs
+++ b/test/display/failure_test.exs
@@ -39,7 +39,7 @@ defmodule FailureTests do
 
   test "only offending lines are displayed for errors" do
     [koan] = SingleArity.all_koans()
-    error = apply(SingleArity, koan, []) |> error()
+    error = apply(SingleArity, koan, []) |> Tuple.to_list |> List.last |> error
 
     assert Failure.format_failure(error) == """
            Assertion failed in some_file.ex:42\nmatch?(:foo, ___)

From f999d6c573136ded1ddc45854c3dfa430b0d22bd Mon Sep 17 00:00:00 2001
From: Shashwat Ganesh <shashwatganesh@protonmail.com>
Date: Thu, 4 Jun 2020 22:55:14 +0530
Subject: [PATCH 3/3] Update the comprehensions test to match the actual koan

---
 test/koans/comprehensions_koans_test.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/koans/comprehensions_koans_test.exs b/test/koans/comprehensions_koans_test.exs
index bcf7498..22f056f 100644
--- a/test/koans/comprehensions_koans_test.exs
+++ b/test/koans/comprehensions_koans_test.exs
@@ -9,7 +9,7 @@ defmodule ComprehensionsTests do
       ["Hello World", "Apple Pie"],
       ["little dogs", "little cats", "big dogs", "big cats"],
       [4, 5, 6],
-      ["Apple Pie", "Pecan Pie", "Pumpkin Pie"],
+      %{"Pecan" => "Pecan Pie", "Pumpkin" => "Pumpkin Pie"}
     ]
 
     test_all(Comprehensions, answers)