test: add flash messaging tests

Author: mychidarko

tests/flash.test.php

@@ -0,0 +1,33 @@
+<?php
+
+test('values can be flashed to session', function () {
+    $message = 'Hello World';
+
+    $flash = new \Leaf\Flash();
+    $flash->set($message);
+
+    expect($flash->display())->toBe($message);
+});
+
+test('flashed values can be used once', function () {
+    $message = 'Hello World, this is me';
+
+    $flash = new \Leaf\Flash();
+    $flash->set($message);
+
+    expect($flash->display())->toBe($message);
+    expect($flash->display())->toBe(null);
+});
+
+test('multiple values can be flashed to session', function () {
+    $message = 'Hello World';
+    $message2 = 'Hello World 2';
+
+    $flash = new \Leaf\Flash();
+    $flash->set($message);
+    $flash->set($message2, 'message2');
+
+    expect($flash->display())->toBe($message);
+    expect($flash->display('message2'))->toBe($message2);
+});
+