[config] Add new MutableConfig

This is to make it easier to override config values at runtime
Mainly created to make it easier to change configs in tests

Author: sunkan

src/MutableConfig.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Config;
+
+final class MutableConfig implements Config
+{
+	use GetConfigTrait;
+
+	/** @var array<string, mixed> */
+	private array $config = [];
+
+	public function __construct(
+		private readonly Config $rootConfig,
+	) {}
+
+	public function getRawValue(string $key): mixed
+	{
+		if (isset($this->config[$key])) {
+			return $this->config[$key];
+		}
+		return $this->rootConfig->get($key);
+	}
+
+	public function setConfigValue(string $key, mixed $value): void
+	{
+		$this->config[$key] = $value;
+	}
+
+	public function resetConfigValue(string $key): void
+	{
+		unset($this->config[$key]);
+	}
+}

tests/MutableConfigTest.php

@@ -0,0 +1,59 @@
+<?php declare(strict_types=1);
+
+namespace Stefna\Config\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Stefna\Config\ArrayConfig;
+use Stefna\Config\MutableConfig;
+use Stefna\Config\Tests\Stub\TestStub;
+
+final class MutableConfigTest extends AbstractConfigTestCase
+{
+	public function testOverrideValue(): void
+	{
+		$config = $this->getConfig();
+		$key = 'testString';
+		$originalValue = $config->get($key);
+		$newValue = 'overrideValue';
+
+		$config->setConfigValue($key, $newValue);
+
+		$this->assertNotSame($originalValue, $newValue);
+		$this->assertSame($newValue, $config->getString($key));
+	}
+
+	public function testOverrideDotKeyValues(): void
+	{
+		$config = $this->getConfig();
+		$key = 'deep.nesting.int';
+		$originalValue = $config->get($key);
+		$newValue = 42;
+
+		$config->setConfigValue($key, $newValue);
+
+		$this->assertNotSame($originalValue, $newValue);
+		$this->assertSame($newValue, $config->getInt($key));
+	}
+
+	public function testOverrideTestValue(): void
+	{
+		$config = $this->getConfig();
+		$key = 'nesting.test';
+		$originalValue = $config->get($key);
+		$newValue = 'overrideValue';
+
+		$config->setConfigValue($key, $newValue);
+
+		$this->assertNotSame($originalValue, $newValue);
+		$this->assertSame($newValue, $config->get($key));
+
+		$config->resetConfigValue($key);
+
+		$this->assertSame($originalValue, $config->get($key));
+	}
+
+	public function getConfig(): MutableConfig
+	{
+		return new MutableConfig($this->getDefaultArrayConfig());
+	}
+}