Create DateTimeStringifier

Author: henriquemoody

src/Stringifiers/DateTimeStringifier.php

@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * This file is part of Respect/Stringifier.
+ *
+ * (c) Henrique Moody <[email protected]>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Stringifier\Stringifiers;
+
+use DateTimeInterface;
+use Respect\Stringifier\Stringifier;
+
+/**
+ * Converts an instance of DateTimeInterface into a string.
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class DateTimeStringifier implements Stringifier
+{
+    /**
+     * @var Stringifier
+     */
+    private $stringifier;
+
+    /**
+     * @var string
+     */
+    private $format;
+
+    /**
+     * Initializes the stringifier.
+     *
+     * @param Stringifier $stringifier
+     * @param string $format
+     */
+    public function __construct(Stringifier $stringifier, string $format)
+    {
+        $this->stringifier = $stringifier;
+        $this->format = $format;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stringify($raw, int $depth): ?string
+    {
+        if (!$raw instanceof DateTimeInterface) {
+            return null;
+        }
+
+        return $this->stringifier->stringify($raw->format($this->format), $depth);
+    }
+}

tests/unit/Stringifiers/DateTimeStringifierTest.php

@@ -0,0 +1,84 @@
+<?php
+
+/*
+ * This file is part of Respect/Stringifier.
+ *
+ * (c) Henrique Moody <[email protected]>
+ *
+ * For the full copyright and license information, please view the "LICENSE.md"
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Stringifier\Test\Stringifiers;
+
+use DateTime;
+use DateTimeImmutable;
+use DateTimeInterface;
+use PHPUnit\Framework\TestCase;
+use Respect\Stringifier\Stringifier;
+use Respect\Stringifier\Stringifiers\DateTimeStringifier;
+
+/**
+ * @covers \Respect\Stringifier\Stringifiers\DateTimeStringifier
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class DateTimeStringifierTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function shouldNotConvertWhenNotInstanceOfDateTimeInterface(): void
+    {
+        $stringifierMock = $this->createMock(Stringifier::class);
+        $stringifierMock
+            ->expects($this->never())
+            ->method('stringify');
+
+        $dateTimeStringifier = new DateTimeStringifier($stringifierMock, 'c');
+
+        self::assertNull($dateTimeStringifier->stringify('NotDateTimeInterface', 0));
+    }
+
+    /**
+     * @test
+     *
+     * @dataProvider validValuesProvider
+     *
+     * @param DateTimeInterface $raw
+     * @param string $format
+     * @param string $expectedValue
+     */
+    public function shouldConvertDateTimeInterfaceToString(
+        DateTimeInterface $raw,
+        string $format,
+        string $expectedValue
+    ): void {
+        $depth = 0;
+
+        $stringifierMock = $this->createMock(Stringifier::class);
+        $stringifierMock
+            ->expects($this->once())
+            ->method('stringify')
+            ->with($expectedValue, $depth)
+            ->willReturn($expectedValue);
+
+        $dateTimeStringifier = new DateTimeStringifier($stringifierMock, $format);
+
+        self::assertSame($expectedValue, $dateTimeStringifier->stringify($raw, $depth));
+    }
+
+    public function validValuesProvider(): array
+    {
+        $dateTime = DateTime::createFromFormat('Y-m-d\TH:i:sP', '2017-12-31T23:59:59+00:00');
+        $dateTimeImmutable = DateTimeImmutable::createFromMutable($dateTime);
+
+        return [
+            [$dateTime, 'd/m/Y', '31/12/2017'],
+            [$dateTime, 'c', '2017-12-31T23:59:59+00:00'],
+            [$dateTimeImmutable, 'Y-m-d H:i:s', '2017-12-31 23:59:59'],
+        ];
+    }
+}