From f82e435aaf5695bc9af6afce226251171a77209e Mon Sep 17 00:00:00 2001
From: Josh Cummings <josh.cummings@gmail.com>
Date: Fri, 27 Mar 2020 15:07:57 -0600
Subject: [PATCH] Add Missing Import

Restored an import that was lost during a backport

Issue gh-4183
---
 .../web/authentication/switchuser/SwitchUserFilterTests.java     | 1 +
 1 file changed, 1 insertion(+)

diff --git a/web/src/test/java/org/springframework/security/web/authentication/switchuser/SwitchUserFilterTests.java b/web/src/test/java/org/springframework/security/web/authentication/switchuser/SwitchUserFilterTests.java
index 5b69080839..c79def87df 100644
--- a/web/src/test/java/org/springframework/security/web/authentication/switchuser/SwitchUserFilterTests.java
+++ b/web/src/test/java/org/springframework/security/web/authentication/switchuser/SwitchUserFilterTests.java
@@ -17,6 +17,7 @@
 package org.springframework.security.web.authentication.switchuser;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import javax.servlet.FilterChain;