Fix tests

tests/fixture/state/exercises/finished_exercise.rs

@@ -0,0 +1,5 @@
+// fake_exercise
+
+fn main() {
+
+}

tests/fixture/state/exercises/pending_exercise.rs

@@ -0,0 +1,7 @@
+// fake_exercise
+
+// I AM NOT DONE
+
+fn main() {
+
+}

tests/fixture/state/exercises/pending_test_exercise.rs

@@ -0,0 +1,4 @@
+// I AM NOT DONE
+
+#[test]
+fn it_works() {}