Added more tests

src/build/token/List.go

@@ -1,5 +1,9 @@
 package token
 
+import (
+	"strings"
+)
+
 // List is a slice of tokens.
 type List []Token
 
@@ -24,3 +28,14 @@ func (list List) LastIndexKind(kind Kind) int {
 
 	return -1
 }
+
+// Text returns the concatenated token text.
+func (list List) Text(source []byte) string {
+	tmp := strings.Builder{}
+
+	for _, t := range list {
+		tmp.WriteString(t.Text(source))
+	}
+
+	return tmp.String()
+}