diff --git a/tests/test_regexp.rs b/tests/test_regexp.rs
--- a/tests/test_regexp.rs
+++ b/tests/test_regexp.rs
@@ -89,6 +89,32 @@ fn test_eval_alternative_dfa() {
 }
 
 #[test]
+fn test_eval_lambda_nfa() {
+	let r = Regexp::new(&String::from("a_")).unwrap();
+	assert!(r.eval(String::from("a")));
+	assert!(!r.eval(String::from("")));
+	assert!(!r.eval(String::from("ab")));
+
+	let r = Regexp::new(&String::from("a|_")).unwrap();
+	assert!(r.eval(String::from("a")));
+	assert!(r.eval(String::from("")));
+	assert!(!r.eval(String::from("b")));
+}
+
+#[test]
+fn test_eval_lambda_dfa() {
+	let r = Regexp::new(&String::from("a_")).unwrap().determinize();
+	assert!(r.eval(String::from("a")));
+	assert!(!r.eval(String::from("")));
+	assert!(!r.eval(String::from("ab")));
+
+	let r = Regexp::new(&String::from("a|_")).unwrap().determinize();
+	assert!(r.eval(String::from("a")));
+	assert!(r.eval(String::from("")));
+	assert!(!r.eval(String::from("b")));
+}
+
+#[test]
 fn test_invalid_asterisk() {
 	let x = Regexp::new(&String::from("*"));
 	assert!(matches!(x, Err(ParsingError::Asterisk{s: _, pos: 0})));