Added test for validating that _all_ tokens can be printed

rhino/src/main/java/org/mozilla/javascript/Token.java

@@ -32,6 +32,7 @@ public static enum CommentType {
     public static final int
             // start enum
             ERROR = -1, // well-known as the only code < EOF
+            FIRST_TOKEN = ERROR,
             EOF = ERROR + 1, // end of file token - (not EOF_CHAR)
             EOL = EOF + 1, // end of line
 
@@ -608,6 +609,12 @@ public static String typeToName(int token) {
                 return "YIELD_STAR";
             case BIGINT:
                 return "BIGINT";
+            case GETPROP_OPTIONAL:
+                return "GETPROP_OPTIONAL";
+            case REF_SPECIAL_OPTIONAL:
+                return "REF_SPECIAL_OPTIONAL";
+            case CALL_OPTIONAL:
+                return "CALL_OPTIONAL";
             case TEMPLATE_LITERAL:
                 return "TEMPLATE_LITERAL";
             case TEMPLATE_CHARS:

rhino/src/test/java/org/mozilla/javascript/TokenTest.java

@@ -0,0 +1,16 @@
+package org.mozilla.javascript;
+
+import static org.junit.Assert.assertNotNull;
+import static org.mozilla.javascript.Token.FIRST_TOKEN;
+import static org.mozilla.javascript.Token.LAST_TOKEN;
+
+import org.junit.Test;
+
+public class TokenTest {
+    @Test
+    public void allTokensHaveAName() {
+        for (int token = FIRST_TOKEN; token < LAST_TOKEN; ++token) {
+            assertNotNull(Token.typeToName(token));
+        }
+    }
+}