Upload Kmake

test/parallel/test-sync-io-option.js

@@ -0,0 +1,39 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const { promisify } = require('util');
+const execFile = promisify(require('child_process').execFile);
+
+// Test that --trace-sync-io works. In particular, a warning should be printed
+// when it is enabled and synchronous I/O happens after the first event loop
+// turn, and no warnings should occur when it is disabled or synchronous I/O
+// happens before the first event loop turn is over.
+
+if (process.argv[2] === 'late-sync-io') {
+  setImmediate(() => {
+    require('fs').statSync(__filename);
+  });
+  return;
+} else if (process.argv[2] === 'early-sync-io') {
+  require('fs').statSync(__filename);
+  return;
+}
+
+(async function() {
+  for (const { execArgv, variant, warnings } of [
+    { execArgv: ['--trace-sync-io'], variant: 'late-sync-io', warnings: 1 },
+    { execArgv: [], variant: 'late-sync-io', warnings: 0 },
+    { execArgv: ['--trace-sync-io'], variant: 'early-sync-io', warnings: 0 },
+    { execArgv: [], variant: 'early-sync-io', warnings: 0 },
+  ]) {
+    const { stdout, stderr } =
+      await execFile(process.execPath, [...execArgv, __filename, variant]);
+    assert.strictEqual(stdout, '');
+    const actualWarnings =
+      stderr.match(/WARNING: Detected use of sync API[\s\S]*statSync/g);
+    if (warnings === 0)
+      assert.strictEqual(actualWarnings, null);
+    else
+      assert.strictEqual(actualWarnings.length, warnings);
+  }
+})().then(common.mustCall());