Added unit test for AvailabilityChecker

Author: dmytro-ch

app/code/Magento/Braintree/Test/Unit/Model/InstantPurchase/CreditCard/AvailabilityCheckerTest.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Braintree\Test\Unit\Model\InstantPurchase\CreditCard;
+
+use Magento\Braintree\Gateway\Config\Config;
+use Magento\Braintree\Model\InstantPurchase\CreditCard\AvailabilityChecker;
+
+/**
+ * @covers \Magento\Braintree\Model\InstantPurchase\CreditCard\AvailabilityChecker
+ */
+class AvailabilityCheckerTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * Testable Object
+     *
+     * @var AvailabilityChecker
+     */
+    private $availabilityChecker;
+
+    /**
+     * @var Config|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $configMock;
+
+    /**
+     * Se Up
+     *
+     * @return void
+     */
+    protected function setUp()
+    {
+        $this->configMock = $this->createMock(Config::class);
+        $this->availabilityChecker = new AvailabilityChecker($this->configMock);
+    }
+
+    /**
+     * Test isAvailable method
+     *
+     * @dataProvider isAvailableDataProvider
+     *
+     * @param bool $isVerify3DSecure
+     * @param bool $expected
+     *
+     * @return void
+     */
+    public function testIsAvailable(bool $isVerify3DSecure, bool $expected)
+    {
+        $this->configMock->expects($this->once())->method('isVerify3DSecure')->willReturn($isVerify3DSecure);
+        $actual = $this->availabilityChecker->isAvailable();
+        self::assertEquals($expected, $actual);
+    }
+
+    /**
+     * Data provider for isAvailable method test
+     *
+     * @return array
+     */
+    public function isAvailableDataProvider()
+    {
+        return [
+            [true, false],
+            [false, true],
+        ];
+    }
+}