diff --git a/server_manager/src/services/mod.rs b/server_manager/src/services/mod.rs
index 4294f06..712f3ac 100644
--- a/server_manager/src/services/mod.rs
+++ b/server_manager/src/services/mod.rs
@@ -360,4 +360,47 @@ mod tests {
         assert!(names.contains(&"sonarr"));
         assert!(names.contains(&"mariadb"));
     }
+
+    #[test]
+    fn test_port_mapping_parse_valid() {
+        let p1 = PortMapping::parse("80").unwrap();
+        assert_eq!(p1.host_port, 80);
+        assert_eq!(p1.container_port, 80);
+        assert_eq!(p1.protocol, Protocol::Tcp);
+        assert_eq!(p1.host_ip, None);
+
+        let p2 = PortMapping::parse("8080:80/udp").unwrap();
+        assert_eq!(p2.host_port, 8080);
+        assert_eq!(p2.container_port, 80);
+        assert_eq!(p2.protocol, Protocol::Udp);
+        assert_eq!(p2.host_ip, None);
+
+        let p3 = PortMapping::parse("127.0.0.1:8080:80/tcp").unwrap();
+        assert_eq!(p3.host_port, 8080);
+        assert_eq!(p3.container_port, 80);
+        assert_eq!(p3.protocol, Protocol::Tcp);
+        assert_eq!(p3.host_ip, Some("127.0.0.1".to_string()));
+    }
+
+    #[test]
+    fn test_port_mapping_parse_invalid_port_format() {
+        assert!(PortMapping::parse("invalid").is_err());
+        assert!(PortMapping::parse("8080:invalid").is_err());
+        assert!(PortMapping::parse("invalid:80").is_err());
+        assert!(PortMapping::parse("127.0.0.1:8080:invalid").is_err());
+        assert!(PortMapping::parse("127.0.0.1:invalid:80").is_err());
+        assert!(PortMapping::parse("65536").is_err());
+    }
+
+    #[test]
+    fn test_port_mapping_parse_unsupported_protocol() {
+        let err = PortMapping::parse("80/sctp").unwrap_err();
+        assert!(err.to_string().contains("Unsupported protocol 'sctp'"));
+    }
+
+    #[test]
+    fn test_port_mapping_parse_invalid_parts() {
+        let err = PortMapping::parse("127.0.0.1:8080:80:90").unwrap_err();
+        assert!(err.to_string().contains("Invalid port format"));
+    }
 }
diff --git a/server_manager/tests/contract_performance_budgets.rs b/server_manager/tests/contract_performance_budgets.rs
index 287a386..5c83e71 100644
--- a/server_manager/tests/contract_performance_budgets.rs
+++ b/server_manager/tests/contract_performance_budgets.rs
@@ -147,6 +147,9 @@ fn test_budget_atomic_write_under_50ms() {
     let test_file = tmp_dir.join("test_file.txt");
     let payload = "A".repeat(64 * 1024); // 64 KiB
 
+    // Warm up filesystem / page cache / directory allocation
+    let _ = atomic_write_str(&test_file, &payload, 0o600);
+
     let start = Instant::now();
     let iterations = 5;
     for _ in 0..iterations {