diff --git a/glox/interpreter/interpreter_test.go b/glox/interpreter/interpreter_test.go
index e3c6cfe..153b319 100644
--- a/glox/interpreter/interpreter_test.go
+++ b/glox/interpreter/interpreter_test.go
@@ -46,6 +46,7 @@ func TestInterpret(t *testing.T) {
 		`let age = 17; if(age>18 or age > 21){ print "can drink"; } else { print "can't drink"; }`: "can't drink",
 		`let count=0; while(count<1){count=count+1;}`:                                              "1",
 		`let count=0; while(count<5){count=count+1;}`:                                              "1\n2\n3\n4\n5",
+		`fun greets(name){print "Hello "+name+"!";}greets("John");`:                                "Hello John!\n<nil>",
 	}
 
 	for code, expected := range fixtures {