fix leveled compaction tests

Signed-off-by: Alex Chi Z <iskyzh@gmail.com>

mini-lsm/src/tests/harness.rs

@@ -338,21 +338,19 @@ pub fn check_compaction_ratio(storage: Arc<MiniLsm>) {
         }) => {
             assert!(l0_sst_num < level0_file_num_compaction_trigger);
             assert!(level_size.len() <= max_levels);
-            for idx in 1..level_size.len() {
-                let prev_size = level_size[idx - 1];
-                let this_size = level_size[idx];
-                if this_size == 0 {
-                    continue;
-                }
+            let last_level_size = *level_size.last().unwrap();
+            let mut multiplier = 1.0;
+            for idx in (1..level_size.len()).rev() {
+                multiplier *= level_size_multiplier as f64;
+                let this_size = level_size[idx - 1];
                 assert!(
                     // do not add hard requirement on level size multiplier considering bloom filters...
-                    this_size as f64 / prev_size as f64 >= (level_size_multiplier as f64 - 0.5),
-                    "L{}/L{}, {}/{}<<{}",
-                    state.levels[idx].0,
+                    this_size as f64 / last_level_size as f64 <= 1.0 / multiplier + 0.5,
+                    "L{}/L_max, {}/{}>>1.0/{}",
                     state.levels[idx - 1].0,
                     this_size,
-                    prev_size,
-                    level_size_multiplier
+                    last_level_size,
+                    multiplier
                 );
             }
             assert!(