diff --git a/macaroons/constraints_test.go b/macaroons/constraints_test.go
index dd97536a..569acea8 100644
--- a/macaroons/constraints_test.go
+++ b/macaroons/constraints_test.go
@@ -1,6 +1,7 @@
 package macaroons_test
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 	"time"
@@ -14,7 +15,7 @@ var (
 	testID                      = []byte("dummyId")
 	testLocation                = "lnd"
 	testVersion                 = macaroon.LatestVersion
-	expectedTimeCaveatSubstring = "time-before " + string(time.Now().Year())
+	expectedTimeCaveatSubstring = fmt.Sprintf("time-before %d", time.Now().Year())
 )
 
 func createDummyMacaroon(t *testing.T) *macaroon.Macaroon {
@@ -67,8 +68,8 @@ func TestTimeoutConstraint(t *testing.T) {
 	}
 
 	// Finally, check that the created caveat has an
-	// acceptable value
-	if strings.HasPrefix(string(testMacaroon.Caveats()[0].Id),
+	// acceptable value.
+	if !strings.HasPrefix(string(testMacaroon.Caveats()[0].Id),
 		expectedTimeCaveatSubstring) {
 		t.Fatalf("Added caveat '%s' does not meet the expectations!",
 			testMacaroon.Caveats()[0].Id)
@@ -90,7 +91,7 @@ func TestIpLockConstraint(t *testing.T) {
 	}
 
 	// Finally, check that the created caveat has an
-	// acceptable value
+	// acceptable value.
 	if string(testMacaroon.Caveats()[0].Id) != "ipaddr 127.0.0.1" {
 		t.Fatalf("Added caveat '%s' does not meet the expectations!",
 			testMacaroon.Caveats()[0].Id)