No empty reports

index.js

@@ -96,15 +96,15 @@ cssLintPlugin.reporter = function(customReporter) {
   }
 
   if (builtInReporter) {
-    output = reporter.startFormat();
+    output = [reporter.startFormat()];
   }
 
   return through.obj(
     function(file, enc, cb) {
       // Only report if CSSLint was ran and errors were found
       if (file.csslint && !file.csslint.success) {
         if (builtInReporter) {
-          output += reporter.formatResults(file.csslint.originalReport, file.path);
+          output.push(reporter.formatResults(file.csslint.originalReport, file.path));
         }
         else {
           reporter(file);
@@ -114,10 +114,14 @@ cssLintPlugin.reporter = function(customReporter) {
       return cb(null, file);
     },
     function(cb) {
+      var report;
+
       if (builtInReporter) {
-        output += reporter.endFormat();
+        output.push(reporter.endFormat());
+        report = output.join('');
 
-        gutil.log(output);
+        // Only print report if the report is not empty
+        report && gutil.log(report);
       }
 
       return cb();

test/fixtures/validCSS.css

@@ -1,3 +1,3 @@
-.foo {
+.is-foo {
   color: red;
 }

test/main.js

@@ -250,7 +250,9 @@ describe('gulp-csslint', function() {
       stream.write(file);
       stream.end();
     });
+  });
 
+  describe('cssLintPlugin.reporter()', function() {
     it('should support built-in CSSLint formatters', sinon.test(function(done) {
       var a = 0;
 
@@ -284,5 +286,39 @@ describe('gulp-csslint', function() {
       lintStream.write(file);
       lintStream.end();
     }));
+
+    it('should not print empty output by built-in CSSLint formatters', sinon.test(function(done) {
+      var a = 0;
+
+      var file = getFile('fixtures/validCSS.css');
+
+      var lintStream = cssLintPlugin();
+      var reporterStream = cssLintPlugin.reporter('text');
+
+      sinon.stub(gutil, 'log');
+
+      reporterStream.on('data', function() {
+        ++a;
+      });
+      lintStream.on('data', function(newFile) {
+        should.exist(newFile.csslint.success);
+        newFile.csslint.success.should.equal(true);
+        reporterStream.write(newFile);
+      });
+      lintStream.once('end', function() {
+        reporterStream.end();
+      });
+
+      reporterStream.once('end', function() {
+        a.should.equal(1);
+        sinon.assert.callCount(gutil.log, 0);
+
+        gutil.log.restore();
+        done();
+      });
+
+      lintStream.write(file);
+      lintStream.end();
+    }));
   });
 });