tests: refactors toBeTruthy and toBeFalsy

tests/Features/Expect/toBeFalsy.php

@@ -0,0 +1,19 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('passes as falsy', function ($value) {
+    expect($value)->toBeFalsy();
+})->with([false, '', null, 0, '0']);
+
+test('passes as not falsy', function ($value) {
+    expect($value)->not->toBeFalsy();
+})->with([true, [1], 'false', 1, -1]);
+
+test('failures', function () {
+    expect(1)->toBeFalsy();
+})->throws(ExpectationFailedException::class);
+
+test('not failures', function () {
+    expect(null)->not->toBeFalsy();
+})->throws(ExpectationFailedException::class);