Create NanStringifier

Author: henriquemoody

src/Stringifiers/NanStringifier.php

@@ -0,0 +1,58 @@
+<?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_float;
+use function is_nan;
+use Respect\Stringifier\Quoter;
+use Respect\Stringifier\Stringifier;
+
+/**
+ * Converts a NaN value into a string.
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class NanStringifier implements Stringifier
+{
+    /**
+     * @var Quoter
+     */
+    private $quoter;
+
+    /**
+     * Initializes the stringifier.
+     *
+     * @param Quoter $quoter
+     */
+    public function __construct(Quoter $quoter)
+    {
+        $this->quoter = $quoter;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function stringify($raw, int $depth): ?string
+    {
+        if (!is_float($raw)) {
+            return null;
+        }
+
+        if (!is_nan($raw)) {
+            return null;
+        }
+
+        return $this->quoter->quote('NaN', $depth);
+    }
+}

tests/unit/Stringifiers/NanStringifierTest.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\Quoter;
+use Respect\Stringifier\Stringifiers\NanStringifier;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \Respect\Stringifier\Stringifiers\NanStringifier
+ *
+ * @author Henrique Moody <[email protected]>
+ */
+final class NanStringifierTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function shouldNotConvertToStringWhenRawValueIsNotAFloat(): void
+    {
+        $raw = 'string';
+        $depth = 0;
+
+        $quoterMock = $this->createMock(Quoter::class);
+        $quoterMock
+            ->expects($this->never())
+            ->method('quote');
+
+        $nanStringifier = new NanStringifier($quoterMock);
+
+        self::assertNull($nanStringifier->stringify($raw, $depth));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldNotConvertToStringWhenRawValueIsANumber(): void
+    {
+        $raw = 1.00000000002;
+        $depth = 0;
+
+        $quoterMock = $this->createMock(Quoter::class);
+        $quoterMock
+            ->expects($this->never())
+            ->method('quote');
+
+        $nanStringifier = new NanStringifier($quoterMock);
+
+        self::assertNull($nanStringifier->stringify($raw, $depth));
+    }
+
+    /**
+     * @test
+     */
+    public function shouldConvertToStringWhenRawValueIsNotANumber(): void
+    {
+        $raw = acos(8);
+        $depth = 0;
+
+        $expected = 'NaN';
+
+        $quoterMock = $this->createMock(Quoter::class);
+        $quoterMock
+            ->expects($this->once())
+            ->method('quote')
+            ->with($expected, $depth)
+            ->willReturn($expected);
+
+        $nanStringifier = new NanStringifier($quoterMock);
+
+        self::assertSame($expected, $nanStringifier->stringify($raw, $depth));
+    }
+}