test: avoid race in file write stream handle tests

test/parallel/test-fs-write-stream-file-handle-2.js

@@ -0,0 +1,33 @@
+'use strict';
+const common = require('../common');
+const fs = require('fs');
+const path = require('path');
+const assert = require('assert');
+const tmpdir = require('../common/tmpdir');
+const file = path.join(tmpdir.path, 'write_stream_filehandle_test.txt');
+const input = 'hello world';
+
+tmpdir.refresh();
+
+fs.promises.open(file, 'w+').then((handle) => {
+  let calls = 0;
+  const {
+    write: originalWriteFunction,
+    writev: originalWritevFunction
+  } = handle;
+  handle.write = function write() {
+    calls++;
+    return Reflect.apply(originalWriteFunction, this, arguments);
+  };
+  handle.writev = function writev() {
+    calls++;
+    return Reflect.apply(originalWritevFunction, this, arguments);
+  };
+  const stream = fs.createWriteStream(null, { fd: handle });
+
+  stream.end(input);
+  stream.on('close', common.mustCall(() => {
+    assert(calls > 0, 'expected at least one call to fileHandle.write or ' +
+    'fileHandle.writev, got 0');
+  }));
+}).then(common.mustCall());

test/parallel/test-fs-write-stream-file-handle.js

@@ -19,26 +19,3 @@ fs.promises.open(file, 'w+').then((handle) => {
     assert.strictEqual(output, input);
   }));
 }).then(common.mustCall());
-
-fs.promises.open(file, 'w+').then((handle) => {
-  let calls = 0;
-  const {
-    write: originalWriteFunction,
-    writev: originalWritevFunction
-  } = handle;
-  handle.write = function write() {
-    calls++;
-    return Reflect.apply(originalWriteFunction, this, arguments);
-  };
-  handle.writev = function writev() {
-    calls++;
-    return Reflect.apply(originalWritevFunction, this, arguments);
-  };
-  const stream = fs.createWriteStream(null, { fd: handle });
-
-  stream.end(input);
-  stream.on('close', common.mustCall(() => {
-    assert(calls > 0, 'expected at least one call to fileHandle.write or ' +
-    'fileHandle.writev, got 0');
-  }));
-}).then(common.mustCall());