Add custom message option for valid-test-description rule

lib/rules/valid-test-description.js

@@ -9,9 +9,28 @@ const astUtils = require('../util/ast');
 
 const defaultTestNames = [ 'it', 'test', 'specify' ];
 
-module.exports = function (context) {
+function inlineOptions(context) {
     const pattern = context.options[0] ? new RegExp(context.options[0]) : /^should/;
     const testNames = context.options[1] ? context.options[1] : defaultTestNames;
+    const message = context.options[2];
+
+    return { pattern, testNames, message };
+}
+
+function objectOptions(options) {
+    const pattern = options.pattern ? new RegExp(options.pattern) : /^should/;
+    const testNames = options.testNames ? options.testNames : defaultTestNames;
+    const message = options.message;
+
+    return { pattern, testNames, message };
+}
+
+module.exports = function (context) {
+    const options = context.options[0];
+
+    const { pattern, testNames, message } = typeof options === 'object' && !(options instanceof RegExp) ?
+        objectOptions(options) :
+        inlineOptions(context);
 
     function isTest(node) {
         return node.callee && node.callee.name && testNames.indexOf(node.callee.name) > -1;
@@ -41,7 +60,7 @@ module.exports = function (context) {
 
             if (isTest(node)) {
                 if (!hasValidOrNoTestDescription(node)) {
-                    context.report(node, `Invalid "${ callee.name }()" description found.`);
+                    context.report(node, message || `Invalid "${ callee.name }()" description found.`);
                 }
             }
         }