diff --git a/src/lib.rs b/src/lib.rs
index 00bbdf3..66a1b23 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,7 +7,7 @@ mod tictoc {
     use pyo3::exceptions::PyException;
     
     #[pyclass]
-    #[derive(Clone)]
+    #[derive(Clone, Debug, PartialEq)]
     struct Results {
         #[pyo3(get)]
         nanos: u128,
@@ -74,6 +74,7 @@ mod tictoc {
             }
         }
     }
+
     #[test]
     fn test_new() {
         let init = Init::new();
@@ -84,17 +85,48 @@ mod tictoc {
     fn test_tic() {
         let mut init = Init::new();
         let time1 = init.time;
-        init.tic();
+        let _ = init.tic();
         let time2 = init.time;
         assert!(time2 > time1)
     }
-    
+
     #[test]
     fn test_toc() {
         let mut init = Init::new();
-        init.tic();
+        let _ = init.tic();
         println!("{}","test");
-        let _ = init.toc();
-        assert!(init.results.nanos > 0)
+        let _ = init.toc(None).unwrap();
+        assert!(init.results.nanos > 0);
+    }
+
+    #[test]
+    fn test_passing_tic_to_toc() {
+        let mut init = Init::new();
+        let tic_obj = init.tic().unwrap();
+        println!("{}","test");
+        let results = init.toc(Some(tic_obj)).unwrap();
+        assert!(init.results.nanos > 0);
+        assert_eq!(init.results,results)
+    }
+
+    #[test]
+    fn test_multiple_calls() {
+        let mut init = Init::new();
+        let first_tic = init.tic().unwrap();
+        println!("{}","test");
+        let second_tic = init.tic().unwrap();
+        println!("{}","test");
+        let results2 = init.toc(Some(second_tic)).unwrap();
+        let results = init.toc(Some(first_tic)).unwrap();
+        assert!(results.nanos > results2.nanos);
+    }
+
+    #[test]
+    fn test_toc_before_tic() {
+        let mut init = Init::new();
+        //assert!(init.toc(None).is_err())
+        pyo3::prepare_freethreaded_python();
+        let e = init.toc(None).unwrap_err();
+        assert_eq!(e.to_string(),"Exception: tic() must be called before toc()")
     }
 }