Fix #59 by capturing FunctionClauseError and reporting error

Author: aweiker

lib/graphql/execution/resolvable.ex

@@ -11,6 +11,7 @@ defmodule GraphQL.Execution.ResolveWrapper do
       {:ok, fun.()}
     rescue
       e in RuntimeError -> {:error, e.message}
+      e in FunctionClauseError -> {:error, "Could not find a resolve function for this query."}
     end
   end
 end

test/graphql/execution/executor_test.exs

@@ -142,7 +142,7 @@ defmodule GraphQL.Execution.Executor.ExecutorTest do
             type: %String{},
             args: %{
               name: %{type: %String{}}
-          },
+            },
             resolve: fn(_, %{name: name}, _) -> "Hello #{name}!!" end,
           }
         }