Adds a new method, isInParallel, to the Testable trait to allow a test to determine its parallel status.

tests/Features/Parallel.php

@@ -0,0 +1,15 @@
+<?php
+
+use Pest\TestSuite;
+
+it('can determine in the test case if it is running in parallel', function () {
+    expect(test()->isInParallel())->toBeTrue();
+})->skip(!TestSuite::getInstance()->isInParallel);
+
+it('can determine in the test case if it is not running in parallel', function () {
+    expect(test()->isInParallel())->toBeFalse();
+})->skip(TestSuite::getInstance()->isInParallel);
+
+it('can skip using the test case based on parallel status', function () {
+    expect(TestSuite::getInstance()->isInParallel)->toBeFalse();
+})->skip(function () { return $this->isInParallel(); });