Merge pull request #25 from michael-rubel/fix/big-number-internal-immutability

Make internal `BigNumber` object immutable 🔧

Author: michael-rubel

src/Collection/Primitive/Number.php

@@ -52,7 +52,9 @@ public function __construct(int|string $number, protected int $scale = 2)
             throw new InvalidArgumentException(static::IMMUTABLE_MESSAGE);
         }
 
-        $this->bigNumber = new BigNumber($this->sanitize($number), $this->scale);
+        $this->bigNumber = new BigNumber(
+            $this->sanitize($number), $this->scale, mutable: false
+        );
     }
 
     /**

tests/Unit/Primitive/NumberTest.php

@@ -234,7 +234,7 @@
 test('number has immutable properties', function () {
     $this->expectException(\InvalidArgumentException::class);
     $valueObject = new Number('1.2000');
-    $this->assertEquals(new BigNumber('1.20', 2), $valueObject->bigNumber);
+    $this->assertEquals(new BigNumber('1.20', 2, false), $valueObject->bigNumber);
     $valueObject->bigNumber = new BigNumber('1.20');
 });
 
@@ -244,6 +244,15 @@
     $valueObject->__construct('1.5000');
 });
 
+test('big number is immutable', function () {
+    Number::macro('isImmutable', function () {
+        return ! $this->bigNumber->isMutable();
+    });
+
+    $number = new Number('1.2000');
+    $this->assertTrue($number->isImmutable());
+});
+
 test('number uses sanitizes numbers trait', function () {
     $this->assertTrue(
         in_array('MichaelRubel\ValueObjects\Concerns\SanitizesNumbers',