fix incorrect relative path when dealing with multiple files having different paths

index.js

@@ -8,10 +8,10 @@ module.exports = function(options){
 }
 
 function transform(options) {
-  options = options || {}
   return function(file, enc, cb){
     var contents
     var transformed
+    var options = options || {}
     if(file.isStream()) {
       return cb(
         new PluginError("gulp-cssnext", "streaming not supported")

test/cssnext.js

@@ -67,3 +67,46 @@ tape("throws on cssnext error", function(test){
   })
   stream.end(file)
 })
+
+tape("Resolves relative paths for consecutive files in different paths", function(test) {
+  var stream = cssnext()
+  var file = new gutil.File({
+    base: "./fixtures/",
+    path: "./fixtures/import.css",
+    contents: new Buffer(
+      fs.readFileSync(
+        path.resolve(__dirname, "./fixtures/import.css"),
+        "utf8"
+      )
+    )
+  })
+  stream.write(file)
+
+  var file2 = new gutil.File({
+    base : "./fixtures/import/",
+    path : "./fixtures/import/index.css",
+    contents : new Buffer(
+      fs.readFileSync(
+        path.resolve(__dirname, "./fixtures/import/index.css"),
+        "utf8"
+      )
+    )
+  })
+  stream.write(file2)
+
+  var count = 0;
+  stream.on("data", function(file){
+
+    test.equal(
+      file.contents.toString(),
+      fs.readFileSync(
+        path.resolve(__dirname, "./expected/index.css"),
+        "utf8"
+      )
+    )
+    ++count
+    if(count == 2) {
+      test.end()
+    }
+  })
+})

test/fixtures/import.css

@@ -0,0 +1 @@
+@import './index.css';

test/fixtures/import/index.css

@@ -0,0 +1 @@
+@import '../index.css';