Fix #94 -- copy-paste considered harmful

Djikstra is alleged to have provided that title for the essay,
I have read. He was a real trickster figure.

src/controller/cycleentries.rs

@@ -458,4 +458,22 @@ mod tests {
         let id = cycle.find_next_id();
         assert_eq!(id, 1);
     }
+
+    #[test]
+    fn filtering() {
+        use crate::data::item_cache::ItemCache;
+        let mut cache = ItemCache::new();
+        let mut cycle = Vec::<String>::new();
+
+        let item = cache.get(&"form-one".to_string());
+        assert!(cycle.add(&item.form_string()));
+        let item2 = cache.get(&"form-two".to_string());
+        assert!(cycle.add(&item2.form_string()));
+        let item3 = cache.get(&"form-three".to_string());
+        cycle.add(&item3.form_string());
+        assert_eq!(cycle.len(), 3);
+
+        assert!(cycle.filter_id(&"form-two"));
+        assert_eq!(cycle.len(), 2);
+    }
 }

src/controller/cycles.rs

@@ -201,10 +201,10 @@ impl CycleData {
             self.utility.filter_id(form_spec);
         }
         if kind.left_hand_ok() {
-            self.utility.filter_id(form_spec);
+            self.left.filter_id(form_spec);
         }
         if kind.right_hand_ok() {
-            self.utility.filter_id(form_spec);
+            self.right.filter_id(form_spec);
         }
     }