test: avoid race in file write stream handle tests

The test previously created two fs.promises.open calls on the
same file with w+ back-to-back, and one of them could fail
when checking the contents of that file if the other happened
to be opening the file for write. Split them into different
tests (with different tmpdir) to avoid the race.

PR-URL: #44380
Refs: nodejs/reliability#354
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>

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());