diff --git a/tests/Assert/XPathFilterTest.php b/tests/Assert/XPathFilterTest.php
new file mode 100644
index 0000000..a6a79e3
--- /dev/null
+++ b/tests/Assert/XPathFilterTest.php
@@ -0,0 +1,103 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SimpleSAML\XML\Test\Assert;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use SimpleSAML\Assert\AssertionFailedException;
+use SimpleSAML\XML\Assert\Assert as XMLAssert;
+use SimpleSAML\XML\Constants as C;
+
+use function str_pad;
+
+/**
+ * Class \SimpleSAML\XML\Assert\XPathFilterTest
+ *
+ * @package simplesamlphp/xml-common
+ */
+#[CoversClass(XMLAssert::class)]
+final class XPathFilterTest extends TestCase
+{
+    /**
+     * @param boolean $shouldPass
+     * @param string $filter
+     */
+    #[DataProvider('provideXPathFilter')]
+    public function testDefaultAllowedXPathFilter(
+        bool $shouldPass,
+        string $filter,
+        array $axes = C::DEFAULT_ALLOWED_AXES,
+        array $functions = C::DEFAULT_ALLOWED_FUNCTIONS,
+    ): void {
+        try {
+            XMLAssert::allowedXPathFilter($filter, $axes, $functions);
+            $this->assertTrue($shouldPass);
+        } catch (AssertionFailedException $e) {
+            $this->assertFalse($shouldPass);
+        }
+    }
+
+
+    /**
+     * @return array<string, array{0: bool, 1: string}>
+     */
+    public static function provideXPathFilter(): array
+    {
+        return [
+            // Axes
+            'ancestor' => [true, 'ancestor::book'],
+            'ancestor-or-self' => [true, 'ancestor-or-self::book'],
+            'attribute' => [true, 'attribute::book'],
+            'child' => [true, 'child::book'],
+            'descendant' => [true, 'descendant::book'],
+            'descendant-or-self' => [true, 'descendant-or-self::book'],
+            'following' => [true, 'following::book'],
+            'following-sibling' => [true, 'following-sibling::book'],
+            'namespace' => [false, 'namespace::book'],
+            'namespace' => [true, 'namespace::book', ['namespace']],
+            'parent' => [true, 'parent::book'],
+            'preceding' => [true, 'preceding::book'],
+            'preceding-sibling' => [true, 'preceding-sibling::book'],
+            'self' => [true, 'self::book'],
+
+            // Functions
+            'boolean' => [false, 'boolean(Data/username/text())'],
+            'ceiling' => [false, 'ceiling(//items/item[1]/price)'],
+            'concat' => [false, "concat('A', '_', 'B')"],
+            'contains' => [false, "contains(//username, 'o')"],
+            'count' => [false, "count(//Sales.Order[Sales.Customer_Order/Sales.Customer/Name = 'Jansen'])"],
+            'false' => [false, '//Sales.Customer[IsGoldCustomer = false()]'],
+            'floor' => [false, 'floor(//items/item[1]/price)'],
+            'id' => [false, 'SalesInvoiceLines[id(1)]'],
+            'lang' => [false, 'lang("en-US")'],
+            'last' => [false, 'last()'],
+            'local-name' => [false, 'local-name(SalesInvoiceLines) '],
+            'name' => [false, 'name(SalesInvoiceLines)'],
+            'namespace-uri' => [false, 'namespace-uri(ReportData)'],
+            'normalize-space' => [false, 'normalize-space(" Hello World ")'],
+            'not' => [true, "//Sales.Customer[not(Name = 'Jansen')]"],
+            'number' => [false, 'number("123")'],
+            'position' => [false, 'position()'],
+            'round' => [false, 'round(//items/item[1]/price)'],
+            'starts-with' => [false, "//Sales.Customer[starts-with(Name, 'Jans')]"],
+            'string' => [false, 'string(123)'],
+            'string-length' => [false, 'string-length(//email)string-length(//email)'],
+            'substring' => [false, "/bookstore/book[substring(title,1,5)='Harry']"],
+            'substring-after' => [false, "/bookstore/book[substring-after(title,1,5)='Harry']"],
+            'substring-before' => [false, "/bookstore/book[substring-before(title,1,5)='Harry']"],
+            'sum' => [false, 'sum(//Sales.Order/TotalPrice)'],
+            'text' => [false, '//lastname/text()'],
+            'translate' => [false, "translate(//email, '@', '_')"],
+            'true' => [false, '//Sales.Customer[IsGoldCustomer = true()]'],
+
+            // Edge-cases
+            'unknown axis' => [false, 'unknown::book'],
+            'unknown function' => [false, 'unknown()'],
+            'too long' => [false, str_pad('a', 120, 'a')],
+        ];
+    }
+}