test: fix test runner colored output test

Author: MoLow

test/fixtures/test-runner/output/arbitrary-output-colored.js

@@ -6,6 +6,7 @@ const fixtures = require('../../../common/fixtures');
 
 (async function run() {
   const test = fixtures.path('test-runner/output/arbitrary-output-colored-1.js');
-  await once(spawn(process.execPath, ['--test', test], { stdio: 'inherit', env: { FORCE_COLOR: 1 } }), 'exit');
-  await once(spawn(process.execPath, ['--test', '--test-reporter', 'tap', test], { stdio: 'inherit', env: { FORCE_COLOR: 1 }  }), 'exit');
+  const reset = fixtures.path('test-runner/output/reset-color-depth.js');
+  await once(spawn(process.execPath, ['-r', reset, '--test', test], { stdio: 'inherit' }), 'exit');
+  await once(spawn(process.execPath, ['-r', reset, '--test', '--test-reporter', 'tap', test], { stdio: 'inherit'  }), 'exit');
 })().then(common.mustCall());

test/fixtures/test-runner/output/reset-color-depth.js

@@ -0,0 +1,5 @@
+'use strict';
+
+// Make tests OS-independent by overriding stdio getColorDepth().
+process.stdout.getColorDepth = () => 8;
+process.stderr.getColorDepth = () => 8;