Create StringableObjectStringifier

Author: henriquemoody

src/Stringifiers/StringableObjectStringifier.php

@@ -0,0 +1,57 @@
+<?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 function is_object;
+use function method_exists;
+use Respect\Stringifier\Stringifier;
+
+/**
+ * Converts a object that implements the __toString() magic method into a string.
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class StringableObjectStringifier implements Stringifier
+{
+    /**
+     * @var Stringifier
+     */
+    private $stringifier;
+
+    /**
+     * Initializes the stringifier.
+     *
+     * @param Stringifier $stringifier
+     */
+    public function __construct(Stringifier $stringifier)
+    {
+        $this->stringifier = $stringifier;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stringify($raw, int $depth): ?string
+    {
+        if (!is_object($raw)) {
+            return null;
+        }
+
+        if (!method_exists($raw, '__toString')) {
+            return null;
+        }
+
+        return $this->stringifier->stringify($raw->__toString(), $depth);
+    }
+}

tests/unit/Stringifiers/StringableObjectStringifierTest.php

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+<?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 Respect\Stringifier\Stringifier;
+use Respect\Stringifier\Stringifiers\StringableObjectStringifier;
+use PHPUnit\Framework\TestCase;
+use stdClass;
+
+/**
+ * @covers \Respect\Stringifier\Stringifiers\StringableObjectStringifier
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class StringableObjectStringifierTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function shouldNotConvertToStringWhenValueIsNotAnObject(): void
+    {
+        $raw = 'not-an-object';
+        $depth = 1;
+
+        $stringifierMock = $this->createMock(Stringifier::class);
+        $stringifierMock
+            ->expects($this->never())
+            ->method('stringify');
+
+        $stringableObjectStringifier = new StringableObjectStringifier($stringifierMock);
+
+        self::assertNull($stringableObjectStringifier->stringify($raw, $depth));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldNotConvertToStringWhenValueIsANonStringableObject(): void
+    {
+        $raw = new stdClass();
+        $depth = 1;
+
+        $stringifierMock = $this->createMock(Stringifier::class);
+        $stringifierMock
+            ->expects($this->never())
+            ->method('stringify');
+
+        $stringableObjectStringifier = new StringableObjectStringifier($stringifierMock);
+
+        self::assertNull($stringableObjectStringifier->stringify($raw, $depth));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldConvertToStringWhenValueIsAnStringableObject(): void
+    {
+        $raw = new StringableObject();
+        $depth = 0;
+
+        $expectedValue = StringableObject::STRING_VALUE;
+
+        $stringifierMock = $this->createMock(Stringifier::class);
+        $stringifierMock
+            ->expects($this->once())
+            ->method('stringify')
+            ->with(StringableObject::STRING_VALUE, $depth)
+            ->willReturn($expectedValue);
+
+        $stringableObjectStringifier = new StringableObjectStringifier($stringifierMock);
+
+        self::assertSame($expectedValue, $stringableObjectStringifier->stringify($raw, $depth));
+    }
+}
+
+final class StringableObject
+{
+    public const STRING_VALUE = 'String';
+
+    public function __toString()
+    {
+        return self::STRING_VALUE;
+    }
+}