diff --git a/tests/unit/Domain/Package/PackageTest.php b/tests/unit/Domain/Package/PackageTest.php
new file mode 100644
index 00000000..1328cc46
--- /dev/null
+++ b/tests/unit/Domain/Package/PackageTest.php
@@ -0,0 +1,87 @@
+<?php
+declare(strict_types = 1);
+
+namespace PackageHealth\PHP\Test\Unit\Domain\Package;
+
+use DateTimeImmutable;
+use PackageHealth\PHP\Domain\Package\Package;
+use PHPUnit\Framework\TestCase;
+
+final class PackageTest extends TestCase {
+  private Package $package;
+  private DateTimeImmutable $createdAt;
+
+  public function setUp(): void {
+    $this->package = new Package(
+      name:           'vendor/project',
+      description:    'An awesome package description',
+      latestVersion:  '1.0',
+      url:            'http://'
+    );
+
+    $this->createdAt = $this->package->getCreatedAt();
+  }
+
+  public function testName(): void {
+    $this->assertSame('vendor/project', $this->package->getName());
+  }
+
+  public function testVendor(): void {
+    $this->assertSame('vendor', $this->package->getVendor());
+  }
+
+  public function testProject(): void {
+    $this->assertSame('project', $this->package->getProject());
+  }
+
+  public function testDescription(): void {
+    $this->assertSame('An awesome package description', $this->package->getDescription());
+  }
+
+  public function testDescriptionHasBeenUpdated(): void {
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getCreatedAt());
+    $this->assertFalse($this->package->isDirty());
+    $this->assertNull($this->package->getUpdatedAt());
+
+    $this->package = $this->package->withDescription('Even awesomer description');
+
+    $this->assertTrue($this->package->isDirty());
+    $this->assertSame('Even awesomer description', $this->package->getDescription());
+    $this->assertSame($this->createdAt, $this->package->getCreatedAt());
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getUpdatedAt());
+  }
+
+  public function testLatestVersion(): void {
+    $this->assertSame('1.0', $this->package->getLatestVersion());
+  }
+
+  public function testLatestversionHasBeenUpdated(): void {
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getCreatedAt());
+    $this->assertFalse($this->package->isDirty());
+    $this->assertNull($this->package->getUpdatedAt());
+
+    $this->package = $this->package->withLatestVersion('1.0.1');
+
+    $this->assertTrue($this->package->isDirty());
+    $this->assertSame('1.0.1', $this->package->getLatestVersion());
+    $this->assertSame($this->createdAt, $this->package->getCreatedAt());
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getUpdatedAt());
+  }
+
+  public function testUrl(): void {
+    $this->assertSame('http://', $this->package->getUrl());
+  }
+
+  public function testUrlHasBeenUpdated(): void {
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getCreatedAt());
+    $this->assertFalse($this->package->isDirty());
+    $this->assertNull($this->package->getUpdatedAt());
+
+    $this->package = $this->package->withUrl('https://');
+
+    $this->assertTrue($this->package->isDirty());
+    $this->assertSame('https://', $this->package->getUrl());
+    $this->assertSame($this->createdAt, $this->package->getCreatedAt());
+    $this->assertInstanceOf(DateTimeImmutable::class, $this->package->getUpdatedAt());
+  }
+}