test(Misc): Add test coverage to the MultiresponseNormalizer

tests/src/Unit/Normalizer/MultiresponseNormalizerTest.php

+<?php
+
+namespace Drupal\Tests\subrequests\Normalizer;
+
+use Drupal\subrequests\Normalizer\MultiresponseNormalizer;
+use Drupal\Tests\UnitTestCase;
+use Symfony\Component\HttpFoundation\Response;
+
+/**
+ * @coversDefaultClass \Drupal\subrequests\Normalizer\MultiresponseNormalizer
+ * @group subrequests
+ */
+class MultiresponseNormalizerTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\subrequests\Normalizer\MultiresponseNormalizer
+   */
+  protected $sut;
+
+  protected function setUp() {
+    parent::setUp();
+    $this->sut = new MultiresponseNormalizer();
+  }
+
+  /**
+   * @dataProvider dataProviderSupportsNormalization
+   * @covers ::supportsNormalization
+   */
+  public function testSupportsNormalization($data, $format, $is_supported) {
+    $actual = $this->sut->supportsNormalization($data, $format);
+    $this->assertSame($is_supported, $actual);
+  }
+
+  public function dataProviderSupportsNormalization() {
+    return [
+      [[Response::create('')], 'multipart-related', TRUE],
+      [[], 'multipart-related', TRUE],
+      [[Response::create('')], 'fail', FALSE],
+      [NULL, 'multipart-related', FALSE],
+      [[Response::create(''), NULL], 'multipart-related', FALSE],
+    ];
+  }
+
+  /**
+   * @covers ::normalize
+   */
+  public function testNormalize() {
+    $delimiter = $this->getRandomGenerator()->string();
+    $data = [Response::create('Foo!'), Response::create('Bar')];
+    $actual = $this->sut->normalize($data, NULL, ['delimiter' => $delimiter]);
+    $this->assertStringStartsWith('--' . $delimiter, $actual);
+    $this->assertStringEndsWith('--' . $delimiter . '--', $actual);
+    $this->assertRegExp("/\r\nFoo!\r\n/", $actual);
+    $this->assertRegExp("/\r\nBar\r\n/", $actual);
+  }
+
+}