feat: add to be absolute of

Author: Katalam

README.md

@@ -60,3 +60,10 @@ This plugin afford math related expectations.
     expect(6)->toBeFactorialOf(3);
     expect(4)->not->toBeFactorialOf(2);
 ```
+
+#### `toBeAbsoluteOf()`
+$$\mid -3 \mid$$
+```php
+    expect(3)->toBeAbsoluteOf(-3);
+    expect(3)->not->toBeAbsoluteOf(4);
+```

src/Expectation.php

@@ -127,4 +127,12 @@ public function toBeFactorialOf(int $number): PestExpectation
 
         return expect($this->value === $factorial)->toBeTrue();
     }
+
+    /**
+     * @return PestExpectation<TValue>
+     */
+    public function toBeAbsoluteOf(int|float $number): PestExpectation
+    {
+        return expect($this->value === abs($number))->toBeTrue("$this->value !== abs($number)");
+    }
 }

tests/toBeAbsolute.php

@@ -0,0 +1,21 @@
+<?php
+
+use PHPUnit\Framework\ExpectationFailedException;
+
+it('passes', function (int|float $number): void {
+    expect($number)->toBeAbsoluteOf($number)
+        ->and($number)->toBeAbsoluteOf(-$number);
+})->with([1, 3, 5, 7, 9, 4.6, 7.8]);
+
+it('passes not', function (int|float $number): void {
+    expect($number + 1)->not->toBeAbsoluteOf($number)
+        ->and($number + 1)->not->toBeAbsoluteOf(-$number);
+})->with([1, 3, 5, 7, 9, 4.6, 7.8]);
+
+test('failures', function (): void {
+    expect(-8)->toBeAbsoluteOf(8);
+})->throws(ExpectationFailedException::class);
+
+test('failures not', function (): void {
+    expect(8)->not->toBeAbsoluteOf(8);
+})->throws(ExpectationFailedException::class);