fixup: add tests

test/parallel/test-cli-options-negation.js

@@ -0,0 +1,39 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const { spawnSync } = require('child_process');
+
+// --warnings is on by default.
+assertHasWarning(spawnWithFlags([]));
+
+// --warnings can be passed alone.
+assertHasWarning(spawnWithFlags(['--warnings']));
+
+// --no-warnings can be passed alone.
+assertHasNoWarning(spawnWithFlags(['--no-warnings']));
+
+// Last flag takes precedence.
+assertHasWarning(spawnWithFlags(['--no-warnings', '--warnings']));
+
+// Non-boolean flags cannot be negated.
+assert(spawnWithFlags(['--no-max-http-header-size']).stderr.toString().includes(
+  '--no-max-http-header-size is an invalid negation because it is not ' +
+  'a boolean option',
+));
+
+// Inexistant flags cannot be negated.
+assert(spawnWithFlags(['--no-i-dont-exist']).stderr.toString().includes(
+  'bad option: --no-i-dont-exist',
+));
+
+function spawnWithFlags(flags) {
+  return spawnSync(process.execPath, [...flags, '-e', 'new Buffer(0)']);
+}
+
+function assertHasWarning(proc) {
+  assert(proc.stderr.toString().includes('Buffer() is deprecated'));
+}
+
+function assertHasNoWarning(proc) {
+  assert(!proc.stderr.toString().includes('Buffer() is deprecated'));
+}