DisallowMultipleLineBreaks: use assertions

Refs #516

lib/rules/disallow-multiple-line-breaks.js

@@ -45,14 +45,20 @@ module.exports.prototype = {
     },
 
     check: function(file, errors) {
-        var lines = file.getLines();
-        for (var i = 1, l = lines.length; i < l; i++) {
-            var line = lines[i];
-            if (line === '' && lines[i - 1] === '') {
-                while (++i < l && lines[i] === '') {}
-                errors.add('Multiple line break', i - 1, 0);
+        // Iterate over all tokens (including comments)
+        file.getTokens().forEach(function(token, index, tokens) {
+            // If there are no trailing tokens, exit early
+            var nextToken = tokens[index + 1];
+            if (!nextToken) {
+                return;
             }
-        }
+
+            errors.assert.linesBetween({
+                token: token,
+                nextToken: nextToken,
+                atMost: 2,
+            });
+        });
     }
 
 };

test/specs/rules/disallow-multiple-line-breaks.js

@@ -29,8 +29,8 @@ describe('rules/disallow-multiple-line-breaks', function() {
 
     it('should report error in the correct location when first line starts with #!', function() {
         var error = checker.checkString('#!/usr/bin/env node\n\n\nx = 1;').getErrorList()[0];
-        assert.equal(error.line, 2);
-        assert.equal(error.column, 0);
+        assert.equal(error.line, 1);
+        assert.equal(error.column, 19);
     });
 
     it('should report only once per each sequence of line breaks', function() {

test/specs/string-checker.js

@@ -40,8 +40,8 @@ describe('modules/string-checker', function() {
             it('should report error in the correct location when first line starts with #!', function() {
                 checker.configure({ disallowMultipleLineBreaks: true });
                 var error = checker.checkString('#!/usr/bin/env node\n\n\nx = 1;').getErrorList()[0];
-                assert.equal(error.line, 2);
-                assert.equal(error.column, 0);
+                assert.equal(error.line, 1);
+                assert.equal(error.column, 19);
             });
         });