diff --git a/tests/FunctionsTest.php b/tests/FunctionsTest.php
new file mode 100644
index 0000000..e8aaf46
--- /dev/null
+++ b/tests/FunctionsTest.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Ramsey\Uuid\Test;
+
+use Ramsey\Uuid\Uuid;
+
+class FunctionsTest extends TestCase
+{
+    public function testV1ReturnsVersion1UuidString()
+    {
+        $v1 = \Ramsey\Uuid\v1();
+
+        $this->assertInternalType('string', $v1);
+        $this->assertSame(Uuid::UUID_TYPE_TIME, Uuid::fromString($v1)->getVersion());
+    }
+
+    public function testV3ReturnsVersion3UuidString()
+    {
+        $ns = Uuid::fromString(Uuid::NAMESPACE_URL);
+        $v3 = \Ramsey\Uuid\v3($ns, 'https://example.com/foo');
+
+        $this->assertInternalType('string', $v3);
+        $this->assertSame(Uuid::UUID_TYPE_HASH_MD5, Uuid::fromString($v3)->getVersion());
+    }
+
+    public function testV4ReturnsVersion4UuidString()
+    {
+        $v4 = \Ramsey\Uuid\v4();
+
+        $this->assertInternalType('string', $v4);
+        $this->assertSame(Uuid::UUID_TYPE_RANDOM, Uuid::fromString($v4)->getVersion());
+    }
+
+    public function testV5ReturnsVersion5UuidString()
+    {
+        $ns = Uuid::fromString(Uuid::NAMESPACE_URL);
+        $v5 = \Ramsey\Uuid\v5($ns, 'https://example.com/foo');
+
+        $this->assertInternalType('string', $v5);
+        $this->assertSame(Uuid::UUID_TYPE_HASH_SHA1, Uuid::fromString($v5)->getVersion());
+    }
+}