diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f70ed70..1640c12 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -41,6 +41,7 @@ jobs:
           - '8.2'
           - '8.3'
           - '8.4'
+          - '8.5'
     steps:
       - uses: actions/checkout@v4
 
@@ -78,6 +79,7 @@ jobs:
           - '8.2'
           - '8.3'
           - '8.4'
+          - '8.5'
     steps:
       - uses: actions/checkout@v4
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2557553..00e344c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Change Log
 
+## Unreleased
+
+- Explicitly nullable params in test helpers.
+- Test last insert IDs with omitted and null names.
+- Upgrade PHPStan to 1.0.
+- Add PHP 8.5 to Github workflow.
+
 ## 2.0.0
 
 Initial release.
diff --git a/composer.json b/composer.json
index 4623bb8..0186a8f 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,7 @@
     "require-dev": {
         "pds/skeleton": "^1.0",
         "phpunit/phpunit": "~9.0",
-        "phpstan/phpstan": "^0.12.82"
+        "phpstan/phpstan": "^1.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/tests/FakeConnection.php b/tests/FakeConnection.php
index 6214fae..f4c4cfd 100644
--- a/tests/FakeConnection.php
+++ b/tests/FakeConnection.php
@@ -41,7 +41,7 @@ public function perform(string $statement, array $values = []) : PDOStatement
         return new PDOStatement();
     }
 
-    public function lastInsertId(string $name = null) : string
+    public function lastInsertId(?string $name = null) : string
     {
         return "{$name}-1";
     }
diff --git a/tests/InsertTest.php b/tests/InsertTest.php
index 0c54c60..972da27 100644
--- a/tests/InsertTest.php
+++ b/tests/InsertTest.php
@@ -16,4 +16,18 @@ public function testGetLastInsertId()
         $actual = $query->getLastInsertId('foo');
         $this->assertSame('foo-1', $actual);
     }
+
+    public function testGetLastInsertId_withoutName()
+    {
+        $query = $this->newQuery();
+        $actual = $query->getLastInsertId();
+        $this->assertSame('-1', $actual);
+    }
+
+    public function testGetLastInsertId_withNullName()
+    {
+        $query = $this->newQuery();
+        $actual = $query->getLastInsertId(null);
+        $this->assertSame('-1', $actual);
+    }
 }
diff --git a/tests/QueryTestCase.php b/tests/QueryTestCase.php
index c8bb14d..d065e7e 100644
--- a/tests/QueryTestCase.php
+++ b/tests/QueryTestCase.php
@@ -19,7 +19,7 @@ protected function getQueryClass()
         return substr(get_class($this), 0, -4);
     }
 
-    protected function newQuery(string $arg = null)
+    protected function newQuery(?string $arg = null)
     {
         if ($arg === null) {
             $arg = new FakeConnection('fake');