diff --git a/src/Assert.php b/src/Assert.php
index 49c3698..1770008 100644
--- a/src/Assert.php
+++ b/src/Assert.php
@@ -6,7 +6,7 @@
 
 use BadMethodCallException; // Requires ext-spl
 use DateTime; // Requires ext-date
-use DateTimeImmutable; // Request ext-date
+use DateTimeImmutable; // Requires ext-date
 use InvalidArgumentException; // Requires ext-spl
 use Throwable;
 use Webmozart\Assert\Assert as Webmozart;
@@ -219,8 +219,8 @@
  * @method static void allContains(iterable<string> $value, string $subString, string $message = '', class-string $exception = '')
  * @method static void nullOrNotContains(string|null $value, string $subString, string $message = '', class-string $exception = '')
  * @method static void allNotContains(iterable<string> $value, string $subString, string $message = '', class-string $exception = '')
- * @method static void nullOrWhitespaceOnly(string|null $value, string $message = '', class-string $exception = '')
- * @method static void allWhitespaceOnly(iterable<string> $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrNotWhitespaceOnly(string|null $value, string $message = '', class-string $exception = '')
+ * @method static void allNotWhitespaceOnly(iterable<string> $value, string $message = '', class-string $exception = '')
  * @method static void nullOrStartsWith(string|null $value, string $prefix, string $message = '', class-string $exception = '')
  * @method static void allStartsWith(iterable<string> $value, string $prefix, string $message = '', class-string $exception = '')
  * @method static void nullOrNotStartsWith(string|null $value, string $prefix, string $message = '', class-string $exception = '')
@@ -315,7 +315,7 @@ final class Assert
 
     /**
      * @param string $name
-     * @param array $arguments
+     * @param array<mixed> $arguments
      */
     public static function __callStatic(string $name, array $arguments): void
     {
@@ -367,7 +367,7 @@ public static function __callStatic(string $name, array $arguments): void
      * Handle nullOr* for either Webmozart or for our custom assertions
      *
      * @param callable $method
-     * @param array $arguments
+     * @param array<mixed> $arguments
      * @return void
      */
     private static function nullOr(callable $method, array $arguments): void
@@ -381,7 +381,7 @@ private static function nullOr(callable $method, array $arguments): void
      * all* for our custom assertions
      *
      * @param callable $method
-     * @param array $arguments
+     * @param array<mixed> $arguments
      * @return void
      */
     private static function all(callable $method, array $arguments): void
@@ -402,6 +402,10 @@ private static function all(callable $method, array $arguments): void
      */
     protected static function valueToString(mixed $value): string
     {
+        if (is_resource($value)) {
+            return 'resource';
+        }
+
         if (null === $value) {
             return 'null';
         }
@@ -430,10 +434,6 @@ protected static function valueToString(mixed $value): string
             return $value::class;
         }
 
-        if (is_resource($value)) {
-            return 'resource';
-        }
-
         if (is_string($value)) {
             return '"' . $value . '"';
         }
diff --git a/src/CustomAssertionTrait.php b/src/CustomAssertionTrait.php
index d593887..d4a7f8d 100644
--- a/src/CustomAssertionTrait.php
+++ b/src/CustomAssertionTrait.php
@@ -17,6 +17,37 @@
 
 /**
  * @package simplesamlphp/assert
+ *
+ * @method static void validDuration(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void stringPlausibleBase64(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validDateTime(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validDateTimeZulu(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void notInArray(mixed $value, array $values, string $message = '', class-string $exception = '')
+ * @method static void validURN(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validURI(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validURL(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validNCName(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void validQName(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidDuration(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrStringPlausibleBase64(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidDateTime(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidDateTimeZulu(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrNotInArray(mixed $value, array $values, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidURN(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidURI(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidURL(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidNCName(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void nullOrValidQName(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidDuration(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allStringPlausibleBase64(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidDateTime(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidDateTimeZulu(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allNotInArray(mixed $value, array $values, string $message = '', class-string $exception = '')
+ * @method static void allValidURN(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidURI(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidURL(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidNCName(mixed $value, string $message = '', class-string $exception = '')
+ * @method static void allValidQName(mixed $value, string $message = '', class-string $exception = '')
  */
 trait CustomAssertionTrait
 {
@@ -144,7 +175,7 @@ private static function validDateTimeZulu(string $value, string $message = ''):
 
     /**
      * @param mixed $value
-     * @param array $values
+     * @param array<mixed> $values
      * @param string $message
      */
     private static function notInArray($value, array $values, string $message = ''): void
diff --git a/tests/Assert/AssertTest.php b/tests/Assert/AssertTest.php
index 953d7dd..d78c678 100644
--- a/tests/Assert/AssertTest.php
+++ b/tests/Assert/AssertTest.php
@@ -14,8 +14,8 @@
 use SimpleSAML\Test\Utils\TestClass;
 use stdClass;
 
-use function getcwd;
 use function opendir;
+use function sys_get_temp_dir;
 
 /**
  * Class \SimpleSAML\Assert\Assert
@@ -57,6 +57,7 @@ public function testAssertionFailingWithCustomExceptionThrowsCustomException():
     public function testUnknownAssertionRaisesBadMethodCallException(): void
     {
         $this->expectException(BadMethodCallException::class);
+        // @phpstan-ignore-next-line
         Assert::thisAssertionDoesNotExist('a', 'b', LogicException::class);
     }
 
@@ -66,6 +67,7 @@ public function testUnknownAssertionRaisesBadMethodCallException(): void
     public function testUnknownNullOrAssertionRaisesBadMethodCallException(): void
     {
         $this->expectException(BadMethodCallException::class);
+        // @phpstan-ignore-next-line
         Assert::nullOrThisAssertionDoesNotExist('a', 'b', LogicException::class);
     }
 
@@ -75,6 +77,7 @@ public function testUnknownNullOrAssertionRaisesBadMethodCallException(): void
     public function testUnknownAllAssertionRaisesBadMethodCallException(): void
     {
         $this->expectException(BadMethodCallException::class);
+        // @phpstan-ignore-next-line
         Assert::allThisAssertionDoesNotExist('a', 'b', LogicException::class);
     }
 
@@ -127,7 +130,7 @@ public function testValueToString(mixed $value, string $expected): void
 
 
     /**
-     * @return array
+     * @return array<string, array{0: mixed, 1: string}>
      */
     public static function provideValue(): array
     {
@@ -137,7 +140,7 @@ public static function provideValue(): array
 
         $otherObject = new stdClass();
 
-        $resource = opendir(getcwd());
+        $resource = opendir(sys_get_temp_dir());
 
         return [
             'null' => [null, 'null'],
diff --git a/tests/Assert/Base64Test.php b/tests/Assert/Base64Test.php
index d758f30..f3a42e9 100644
--- a/tests/Assert/Base64Test.php
+++ b/tests/Assert/Base64Test.php
@@ -35,7 +35,7 @@ public function testStringPlausibleBase64(bool $shouldPass, string $name): void
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideBase64(): array
     {
diff --git a/tests/Assert/DateTimeTest.php b/tests/Assert/DateTimeTest.php
index 7d139bf..fa40a5c 100644
--- a/tests/Assert/DateTimeTest.php
+++ b/tests/Assert/DateTimeTest.php
@@ -52,7 +52,7 @@ public function testValidDateTimeZulu(bool $shouldPass, string $timestamp): void
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideDateTime(): array
     {
@@ -68,7 +68,7 @@ public static function provideDateTime(): array
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideDateTimeZulu(): array
     {
diff --git a/tests/Assert/DurationTest.php b/tests/Assert/DurationTest.php
index f8966a5..61a7f25 100644
--- a/tests/Assert/DurationTest.php
+++ b/tests/Assert/DurationTest.php
@@ -35,7 +35,7 @@ public function testValidDuration(bool $shouldPass, string $duration): void
 
 
     /**
-     * @return array
+     * @return array<int, array{0: bool, 1: string}>
      */
     public static function provideDuration(): array
     {
diff --git a/tests/Assert/NCNameTest.php b/tests/Assert/NCNameTest.php
index c59de75..9e9dc19 100644
--- a/tests/Assert/NCNameTest.php
+++ b/tests/Assert/NCNameTest.php
@@ -35,7 +35,7 @@ public function testValidNCName(bool $shouldPass, string $name): void
 
 
     /**
-     * @return array
+     * @return array<int, array{0: bool, 1: string}>
      */
     public static function provideNCName(): array
     {
diff --git a/tests/Assert/NotInArrayTest.php b/tests/Assert/NotInArrayTest.php
index 394f578..e90da9d 100644
--- a/tests/Assert/NotInArrayTest.php
+++ b/tests/Assert/NotInArrayTest.php
@@ -22,7 +22,7 @@ final class NotInArrayTest extends TestCase
      * @dataProvider provideNotInArray
      * @param boolean $shouldPass
      * @param mixed $item
-     * @param array $arr
+     * @param array<mixed> $arr
      */
     public function testnotInArray(bool $shouldPass, $item, array $arr): void
     {
@@ -36,7 +36,7 @@ public function testnotInArray(bool $shouldPass, $item, array $arr): void
 
 
     /**
-     * @return array
+     * @return array<int, array{0: bool, 1: int, 2: array{0: int}}>
      */
     public static function provideNotInArray(): array
     {
diff --git a/tests/Assert/QNameTest.php b/tests/Assert/QNameTest.php
index 24ba015..b60d660 100644
--- a/tests/Assert/QNameTest.php
+++ b/tests/Assert/QNameTest.php
@@ -35,7 +35,7 @@ public function testValidQName(bool $shouldPass, string $name): void
 
 
     /**
-     * @return array
+     * @return array<int, array{0: bool, 1: string}>
      */
     public static function provideQName(): array
     {
diff --git a/tests/Assert/URITest.php b/tests/Assert/URITest.php
index 9f5ba6c..92d5cb2 100644
--- a/tests/Assert/URITest.php
+++ b/tests/Assert/URITest.php
@@ -69,7 +69,7 @@ public function testValidURN(bool $shouldPass, string $urn): void
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideURI(): array
     {
@@ -84,7 +84,7 @@ public static function provideURI(): array
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideURL(): array
     {
@@ -99,7 +99,7 @@ public static function provideURL(): array
 
 
     /**
-     * @return array
+     * @return array<string, array{0: bool, 1: string}>
      */
     public static function provideURN(): array
     {