diff --git a/src/config.rs b/src/config.rs
index 5f4f796..a78deaf 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -272,16 +272,6 @@ mod tests {
         assert!(matches!(err, ConfigError::SerdeJson(_)));
     }
 
-    /// Test that pretty-printed default JSON includes engine, poll
-    /// interval, and engine config path.
-    #[test]
-    fn dump_default_config_contains_engine() {
-        let dumped = dump_default_config();
-        assert!(dumped.contains(r#""engine": "threshold""#));
-        assert!(dumped.contains(r#""scale_poll_secs": 10.0"#));
-        assert!(dumped.contains(r#""/etc/io-thread-controller.d/engines""#));
-    }
-
     /// Test that serde defaults for min/max threads, host CPU ceiling,
     /// and cooldown match `Config::default()`.
     #[test]
diff --git a/src/engines/mod.rs b/src/engines/mod.rs
index e96fac2..6855e0e 100644
--- a/src/engines/mod.rs
+++ b/src/engines/mod.rs
@@ -247,30 +247,6 @@ pub fn load_registered_engine(
 mod tests {
     use super::*;
 
-    /// Test that `ScaleAction::target`/`Display` cover None/Up/Down
-    /// variants.
-    #[test]
-    fn scale_action_target_and_display() {
-        assert_eq!(ScaleAction::None.target(), None);
-        assert_eq!(ScaleAction::Up(4).target(), Some(4));
-        assert_eq!(ScaleAction::Down(2).target(), Some(2));
-        assert_eq!(ScaleAction::Revert(3).target(), Some(3));
-
-        assert_eq!(ScaleAction::None.to_string(), "none");
-        assert_eq!(ScaleAction::Up(1).to_string(), "up");
-        assert_eq!(ScaleAction::Down(1).to_string(), "down");
-        assert_eq!(ScaleAction::Revert(1).to_string(), "revert");
-    }
-
-    /// Test that `InstanceDecision::new` stores the VM id and
-    /// `ScaleAction` unchanged.
-    #[test]
-    fn instance_decision_new_preserves_fields() {
-        let decision = InstanceDecision::new("vm-1", ScaleAction::Up(5));
-        assert_eq!(decision.instance_id, "vm-1");
-        assert_eq!(decision.decision, ScaleAction::Up(5));
-    }
-
     /// Test that registry loads the threshold engine by name and errors
     /// on unknown engines.
     #[test]
diff --git a/src/engines/threshold.rs b/src/engines/threshold.rs
index cfe08f1..6aa2b70 100644
--- a/src/engines/threshold.rs
+++ b/src/engines/threshold.rs
@@ -765,26 +765,4 @@ mod tests {
             ScaleAction::Revert(4)
         );
     }
-
-    /// Test that a missing `threshold.json` still builds an engine with
-    /// defaults.
-    #[test]
-    fn missing_config_file_uses_defaults() {
-        let dir = tempfile::tempdir().unwrap();
-        let engine =
-            ThresholdEngine::from_config_dir(&Path::new(dir.path().to_str().unwrap())).unwrap();
-        assert_eq!(engine.name(), super::ENGINE_NAME);
-        let _ = engine.config();
-    }
-
-    /// Test that CPU utilisation below scale-up/down thresholds yields
-    /// Hold/`None`.
-    #[rstest]
-    #[tokio::test]
-    async fn evaluate_holds_when_util_below_thresholds(#[future] instance: Arc<Instance>) {
-        let instance = instance.await;
-        let engine = ThresholdEngine::new(ThresholdConfig::default());
-        let action = engine.evaluate(&instance, &context()).await;
-        assert_eq!(action, ScaleAction::None);
-    }
 }
diff --git a/src/instance.rs b/src/instance.rs
index ec2a3c3..64da380 100644
--- a/src/instance.rs
+++ b/src/instance.rs
@@ -665,18 +665,6 @@ mod tests {
         assert!(closed.load(Ordering::Relaxed));
     }
 
-    /// Test that `Display` for an instance prints the bare VM id.
-    #[test]
-    fn display_trims_instance_id() {
-        let instance = Instance::new(
-            "  vm-1  ".to_string(),
-            Path::new(""),
-            1,
-            SnapshotClient { threads: 1 },
-        );
-        assert_eq!(instance.to_string(), "vm-1");
-    }
-
     use super::{TaskCpuSample, compute_per_worker_util};
 
     fn task(tid: i32, name: &str, cpu_ticks: u64) -> TaskCpuSample {
diff --git a/src/util.rs b/src/util.rs
index 67d9e84..bfe2f81 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -142,30 +142,3 @@ macro_rules! path {
         }
     };
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    /// Test that relative `Path` values are stored unchanged.
-    #[test]
-    fn relative_paths_are_unchanged() {
-        let path = Path::new("relative/sock");
-        assert_eq!(path.as_os_str(), OsStr::new("relative/sock"));
-    }
-
-    /// Test that absolute `Path` values stay absolute under the default
-    /// root.
-    #[test]
-    fn absolute_paths_keep_absolute_form_under_default_root() {
-        let path = Path::new("/var/run/example.sock");
-        assert_eq!(path.as_os_str(), OsStr::new("/var/run/example.sock"));
-    }
-
-    /// Test that `FromStr` builds a `Path` from a string.
-    #[test]
-    fn from_str_builds_path() {
-        let path: Path = "tmp/example".parse().unwrap();
-        assert_eq!(path.as_os_str(), OsStr::new("tmp/example"));
-    }
-}