diff --git a/Tests/SwiftParserDiagnosticsTest/DiagnosticInfrastructureTests.swift b/Tests/SwiftParserDiagnosticsTest/DiagnosticInfrastructureTests.swift
index 3d45835f06b..3e4e2ae3167 100644
--- a/Tests/SwiftParserDiagnosticsTest/DiagnosticInfrastructureTests.swift
+++ b/Tests/SwiftParserDiagnosticsTest/DiagnosticInfrastructureTests.swift
@@ -1,15 +1,3 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
 import SwiftDiagnostics
 import SwiftParserDiagnostics
 import XCTest
@@ -36,4 +24,17 @@ class DiagnosticInfrastructureTests: XCTestCase {
       MessageID(domain: "SwiftParser", id: "StaticParserFixIt.insertSemicolon")
     )
   }
+  public func testCaseOutsideOfSwitchDiagnosticSeverityAndID() {
+    let diagnostic = StaticParserError.caseOutsideOfSwitchOrEnum
+
+    XCTAssertEqual(
+      diagnostic.diagnosticID,
+      MessageID(
+        domain: "SwiftParser",
+        id: "StaticParserError.caseOutsideOfSwitchOrEnum"
+      )
+    )
+
+    XCTAssertEqual(diagnostic.severity, DiagnosticSeverity.error)
+  }
 }