Auto-add `allowedStartRules` to test options for `changeAST` and `reportError` methods if it not defined

lib/compiler/passes/report-undefined-rules.js

@@ -24,19 +24,15 @@ function reportUndefinedRules( ast, options ) {
 
     check( ast );
 
-    if ( options.allowedStartRules ) {
+    options.allowedStartRules.forEach( rule => {
 
-        options.allowedStartRules.forEach( rule => {
+        if ( ! asts.findRule( ast, rule ) ) {
 
-            if ( ! asts.findRule( ast, rule ) ) {
+            throw new GrammarError( `Start rule "${ rule }" is not defined.` );
 
-                throw new GrammarError( `Start rule "${ rule }" is not defined.` );
+        }
-
-            }
-
-        } );
 
-    }
+    } );
 
 }
 

test/spec/unit/compiler/passes/helpers.js

@@ -55,6 +55,14 @@ module.exports = function ( chai, utils ) {
 
         const ast = parser.parse( grammar );
 
+        if ( ! options.allowedStartRules ) {
+
+            options.allowedStartRules = ast.rules.length > 0
+                ? [ ast.rules[ 0 ].name ]
+                : [];
+
+        }
+
         utils.flag( this, "object" )( ast, options );
 
         this.assert(
@@ -73,6 +81,14 @@ module.exports = function ( chai, utils ) {
 
         const ast = parser.parse( grammar );
 
+        if ( ! options.allowedStartRules ) {
+
+            options.allowedStartRules = ast.rules.length > 0
+                ? [ ast.rules[ 0 ].name ]
+                : [];
+
+        }
+
         let passed, result;
 
         try {