diff --git a/.github/workflows/testo.yml b/.github/workflows/testo.yml
index 174bb5a..811fc83 100644
--- a/.github/workflows/testo.yml
+++ b/.github/workflows/testo.yml
@@ -14,3 +14,4 @@ jobs:
         ['ubuntu-latest']
       dependencies: >-
         ['lowest', 'highest']
+      ini-values: memory_limit=-1, zend.assertions=1
diff --git a/tests/src/LockTest.php b/tests/src/LockTest.php
index 3ae872d..b95a21f 100644
--- a/tests/src/LockTest.php
+++ b/tests/src/LockTest.php
@@ -6,6 +6,7 @@
 
 use Mockery as m;
 use Mockery\MockInterface;
+use Ramsey\Uuid\Uuid;
 use RoadRunner\Lock\DTO\V1BETA1\Request;
 use RoadRunner\Lock\DTO\V1BETA1\Response;
 use RoadRunner\Lock\Lock;
@@ -14,8 +15,11 @@
 use Spiral\Goridge\RPC\RPCInterface;
 use Testo\Assert;
 use Testo\Assert\ExpectException;
+use Testo\Core\Exception\SkipTest;
 use Testo\Data\DataProvider;
+use Testo\Expect;
 use Testo\Lifecycle\BeforeTest;
+use Testo\Skip;
 use Testo\Test;
 
 #[Test]
@@ -79,6 +83,26 @@ public static function resultDataProvider(): \Traversable
         yield [false];
     }
 
+    public static function negativeTimeDataProvider(): \Generator
+    {
+        yield 'lock ttl' => ['lock', ['resource', 'uuid', -300]];
+        yield 'lock waitTTL' => ['lock', ['resource', 'uuid', 0, -300]];
+        yield 'lockRead ttl' => ['lockRead', ['resource', 'uuid', -300]];
+        yield 'lockRead waitTTL' => ['lockRead', ['resource', 'uuid', 0, -300]];
+        yield 'updateTTL ttl' => ['updateTTL', ['resource', 'uuid', -300]];
+    }
+
+    public static function compoundIntervalDataProvider(): \Generator
+    {
+        yield 'minutes and seconds' => [new \DateInterval('PT1M30S'), 90_000_000];
+        yield 'hours' => [new \DateInterval('PT1H'), 3_600_000_000];
+        yield 'days' => [new \DateInterval('P1D'), 86_400_000_000];
+
+        $interval = new \DateInterval('PT1S');
+        $interval->f = 0.5;
+        yield 'fraction of a second' => [$interval, 1_500_000];
+    }
+
     #[DataProvider('lockTypeDataProvider')]
     public function testLock(
         string $method,
@@ -199,34 +223,50 @@ public function testExistsWithId(bool $result): void
         Assert::same($this->lock->exists('resource', 'some-id'), $result);
     }
 
-    #[ExpectException(\LogicException::class)]
-    public function testLockNegativeTtl(): void
+    #[DataProvider('negativeTimeDataProvider')]
+    public function testNegativeTimeFailsAssertion(string $method, array $args): void
     {
-        $this->lock->lock('resource', 'uuid', -300);
-    }
+        if (\ini_get('zend.assertions') !== '1') {
+            throw new SkipTest('The negative time check is an assert(), inactive unless zend.assertions=1');
+        }
 
-    #[ExpectException(\LogicException::class)]
-    public function testLockNegativeWaitTtl(): void
-    {
-        $this->lock->lock('resource', 'uuid', 0, -300);
+        Expect::exception(\AssertionError::class);
+        $this->lock->$method(...$args);
     }
 
-    #[ExpectException(\LogicException::class)]
-    public function testLockReadNegativeTtl(): void
+    #[Skip('Bug: the docblock promises InvalidArgumentException for a negative ttl, but the check is an assert(); with assertions off the negative value is sent to RoadRunner')]
+    #[DataProvider('negativeTimeDataProvider')]
+    #[ExpectException(\InvalidArgumentException::class)]
+    public function testNegativeTimeThrowsInvalidArgumentException(string $method, array $args): void
     {
-        $this->lock->lock('resource', 'uuid', -300);
+        $this->lock->$method(...$args);
     }
 
-    #[ExpectException(\LogicException::class)]
-    public function testLockReadNegativeWaitTtl(): void
+    #[Skip('Bug: convertTimeToMicroseconds() reads only the seconds field of a DateInterval (format("%s")), dropping minutes, hours, days and microseconds')]
+    #[DataProvider('compoundIntervalDataProvider')]
+    public function testCompoundDateIntervalTtl(\DateInterval $ttl, int $expectedTtl): void
     {
-        $this->lock->lockRead('resource', 'uuid', 0, -300);
+        $this->rpc->shouldReceive('call')
+            ->once()
+            ->withArgs(static fn(string $method, Request $request): bool => $request->getTtl() === $expectedTtl)
+            ->andReturn(new Response(['ok' => true]));
+
+        Assert::true($this->lock->updateTTL('resource', 'some-id', $ttl));
     }
 
-    #[ExpectException(\LogicException::class)]
-    public function testUpdateNegativeWaitTtl(): void
+    public function testLockGeneratesUuidByDefault(): void
     {
-        $this->lock->updateTTL('resource', 'uuid', -300);
+        $rpc = m::mock(RPCInterface::class);
+        $rpc->shouldReceive('withCodec')->andReturnSelf();
+        $rpc->shouldReceive('call')
+            ->once()
+            ->withArgs(static fn(string $method, Request $request): bool => Uuid::isValid($request->getId()))
+            ->andReturn(new Response(['ok' => true]));
+
+        $id = (new Lock($rpc))->lock('resource');
+
+        Assert::string($id);
+        Assert::same(Uuid::fromString($id)->getFields()->getVersion(), 4);
     }
 
     #[BeforeTest]
diff --git a/tests/src/UuidLockIdGeneratorTest.php b/tests/src/UuidLockIdGeneratorTest.php
new file mode 100644
index 0000000..39ae691
--- /dev/null
+++ b/tests/src/UuidLockIdGeneratorTest.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace RoadRunner\Lock\Tests;
+
+use Mockery as m;
+use Ramsey\Uuid\Uuid;
+use Ramsey\Uuid\UuidFactoryInterface;
+use RoadRunner\Lock\UuidLockIdGenerator;
+use Testo\Assert;
+use Testo\Test;
+
+#[Test]
+final class UuidLockIdGeneratorTest
+{
+    public function testGeneratesUuidV4ByDefault(): void
+    {
+        $generator = new UuidLockIdGenerator();
+
+        $id = $generator->generate();
+
+        Assert::true(Uuid::isValid($id));
+        Assert::same(Uuid::fromString($id)->getFields()->getVersion(), 4);
+        Assert::notSame($generator->generate(), $id);
+    }
+
+    public function testUsesGivenFactory(): void
+    {
+        $uuid = Uuid::fromString('2d1e4f7a-8b3c-4d5e-9f60-718293a4b5c6');
+        $factory = m::mock(UuidFactoryInterface::class);
+        $factory->shouldReceive('uuid4')->once()->andReturn($uuid);
+
+        Assert::same((new UuidLockIdGenerator($factory))->generate(), '2d1e4f7a-8b3c-4d5e-9f60-718293a4b5c6');
+    }
+}