feat(expect): add more methods

tests/Expect/toEqualIgnoringCase.php

@@ -0,0 +1,15 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('pass', function () {
+    expect('hello')->toEqualIgnoringCase('HELLO');
+});
+
+test('failures', function () {
+    expect('hello')->toEqualIgnoringCase('BAR');
+})->throws(ExpectationFailedException::class);
+
+test('not failures', function () {
+    expect('HELLO')->not->toEqualIgnoringCase('HelLo');
+})->throws(ExpectationFailedException::class);