fix big file test

test/big.js

@@ -54,11 +54,11 @@ tape('read', function (t) {
   }
 
   const fuse = new Fuse(mnt, ops, { debug: !true, autoCache: true })
-  fuse.mount(function (err) {
+  let fd = 0
-    t.error(err, 'no error')
 
-    fs.open(path.join(mnt, 'test'), 'w+', function (_, fd) {
   run(
+    (_, cb) => fuse.mount(cb),
+    open,
     (_, cb) => fs.fstat(fd, cb),
     checkSize(0),
     (_, cb) => fs.ftruncate(fd, 4 * 1024 * 1024 * 1024 + 1, cb),
@@ -72,6 +72,8 @@ tape('read', function (t) {
     (_, cb) => fs.write(fd, Buffer.alloc(4096), 0, 4096, 6 * 1024 * 1024 * 1024, cb),
     (_, cb) => fs.fstat(fd, cb),
     checkSize(6 * 1024 * 1024 * 1024 + 4096),
+    (_, cb) => fs.close(fd, cb),
+    open,
     (_, cb) => fs.read(fd, Buffer.alloc(4096), 0, 4096, 0, cb),
     (_, cb) => fs.read(fd, Buffer.alloc(4096), 0, 4096, 4 * 1024 * 1024 * 1024, cb),
     (_, cb) => fs.read(fd, Buffer.alloc(4096), 0, 4096, 6 * 1024 * 1024 * 1024, cb),
@@ -83,8 +85,13 @@ tape('read', function (t) {
       t.end()
     }
   )
+
+  function open (_, cb) {
+    fs.open(path.join(mnt, 'test'), 'a+', function (_, res) {
+      fd = res
+      cb()
     })
-  })
+  }
 
   function checkSize (n) {
     return ({ size}, cb) => {
@@ -92,13 +99,14 @@ tape('read', function (t) {
       cb()
     }
   }
-})
 
-function run (...fns) {
+  function run (...fns) {
     const all = [...fns]
     tick()
-  function tick (_, val) {
+    function tick (err, val) {
+      t.error(err, 'no error')
       const next = all.shift()
       if (next) next(val, tick)
     }
-}
+  }
+})