diff --git a/net/ntp/ntp_test.go b/net/ntp/ntp_test.go
index 71767f4..ded1930 100644
--- a/net/ntp/ntp_test.go
+++ b/net/ntp/ntp_test.go
@@ -70,3 +70,49 @@ func TestBeforeAfterWithFraction(t *testing.T) {
     }
 }
 
+func TestBeforeAfterVariousCases(t *testing.T) {
+    // Case 1: Both Seconds and Fraction are zero
+    t1 := ntp.Time64{Seconds: 0, Fraction: 0}
+    t2 := ntp.Time64{Seconds: 0, Fraction: 0}
+
+    if t1.Before(t2) {
+        t.Errorf("t1 should not be before t2 when both are zero")
+    }
+    if t1.After(t2) {
+        t.Errorf("t1 should not be after t2 when both are zero")
+    }
+
+    // Case 2: Non-zero Seconds, zero Fraction
+    t3 := ntp.Time64{Seconds: 1, Fraction: 0}
+    t4 := ntp.Time64{Seconds: 2, Fraction: 0}
+
+    if !t3.Before(t4) {
+        t.Errorf("t3 must be before t4 with non-zero seconds")
+    }
+    if !t4.After(t3) {
+        t.Errorf("t4 must be after t3 with non-zero seconds")
+    }
+
+    // Case 3: Zero Seconds, non-zero Fraction
+    t5 := ntp.Time64{Seconds: 0, Fraction: 100}
+    t6 := ntp.Time64{Seconds: 0, Fraction: 200}
+
+    if !t5.Before(t6) {
+        t.Errorf("t5 must be before t6 with non-zero fraction")
+    }
+    if !t6.After(t5) {
+        t.Errorf("t6 must be after t5 with non-zero fraction")
+    }
+
+    // Case 4: Both Seconds and Fraction are non-zero
+    t7 := ntp.Time64{Seconds: 1, Fraction: 100}
+    t8 := ntp.Time64{Seconds: 1, Fraction: 200}
+
+    if !t7.Before(t8) {
+        t.Errorf("t7 must be before t8 with both fields non-zero")
+    }
+    if !t8.After(t7) {
+        t.Errorf("t8 must be after t7 with both fields non-zero")
+    }
+}
+