Fix tests

tests/fixture/state/exercises/finished_exercise.rs

@@ -1,5 +1 @@
-// fake_exercise
-
-fn main() {
-
-}
+fn main() {}

tests/fixture/state/exercises/pending_exercise.rs

@@ -1,5 +1 @@
-// fake_exercise
-
-fn main() {
-
-}
+fn main() {}

tests/fixture/state/exercises/pending_test_exercise.rs

@@ -1,2 +1,4 @@
+fn main() {}
+
 #[test]
 fn it_works() {}