diff --git a/Tests/SplashTests/Tests/DeclarationTests.swift b/Tests/SplashTests/Tests/DeclarationTests.swift
index bf1c646..30a4fc8 100644
--- a/Tests/SplashTests/Tests/DeclarationTests.swift
+++ b/Tests/SplashTests/Tests/DeclarationTests.swift
@@ -493,6 +493,31 @@ final class DeclarationTests: SyntaxHighlighterTestCase {
             .plainText("}")
         ])
     }
+        
+    func testFunctionDeclarationWithInOutParameter() {
+        let components = highlighter.highlight("func swapValues(value1: inout Int, value2: inout Int) { }")
+        
+        XCTAssertEqual(components, [
+            .token("func", .keyword),
+            .whitespace(" "),
+            .plainText("swapValues(value1:"),
+            .whitespace(" "),
+            .token("inout", .keyword),
+            .whitespace(" "),
+            .token("Int", .type),
+            .plainText(","),
+            .whitespace(" "),
+            .plainText("value2:"),
+            .whitespace(" "),
+            .token("inout", .keyword),
+            .whitespace(" "),
+            .token("Int", .type),
+            .whitespace(" "),
+            .plainText("{"),
+            .whitespace(" "),
+            .plainText("}")
+        ])
+    }
 
     func testAllTestsRunOnLinux() {
         XCTAssertTrue(TestCaseVerifier.verifyLinuxTests((type(of: self)).allTests))