Do not shrink CSS if the file is empty (see stoyan/cssshrink#16)

Author: Tor Røttum

index.js

@@ -22,7 +22,9 @@ function cssShrink() {
     }
 
     if (file.isBuffer()) {
-      	file.contents = cssShrinkIt(file.contents.toString());
+        if (file.contents.toString().trim() !== '') {
+          file.contents = cssShrinkIt(file.contents.toString());
+        }
     }
 
     // make sure the file goes through the next gulp plugin

test.js

@@ -23,6 +23,28 @@ describe('gulp-cssshrink', function() {
       });
 
 
+      done();
+    });
+  });
+
+  describe('with empty file', function() {
+    it('should not return anything or crash', function(done) {
+
+      var fakeFile = new File({
+        contents: new Buffer('')
+      });
+
+      var myCSSShrink = cssshrink();
+      myCSSShrink.write(fakeFile);
+
+      myCSSShrink.once('data', function(file) {
+        assert(file.isBuffer());
+
+        // check if the CSS was shrunken
+        assert.equal(file.contents.toString(), '');
+      });
+
+
       done();
     });
   });