Add @TestExtension DummyCrumbIssuer to provide second CrumbIssuer descriptor in test environment

Author: AmoghParmar

test/src/test/java/hudson/security/csrf/GlobalCrumbIssuerConfigurationTest.java

@@ -3,10 +3,12 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsString;
 
+import jakarta.servlet.ServletRequest;
 import org.htmlunit.html.HtmlPage;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.jvnet.hudson.test.JenkinsRule;
+import org.jvnet.hudson.test.TestExtension;
 import org.jvnet.hudson.test.junit.jupiter.WithJenkins;
 
 @WithJenkins
@@ -51,4 +53,33 @@ void csrfSectionShownWhenCsrfProtectionDisabled() throws Exception {
             GlobalCrumbIssuerConfiguration.DISABLE_CSRF_PROTECTION = original;
         }
     }
+
+    @TestExtension
+    public static class DummyCrumbIssuer extends CrumbIssuer {
+
+        @Override
+        public String getCrumbRequestField() {
+            return "dummy";
+        }
+
+        @Override
+        public String issueCrumb(ServletRequest request, String salt) {
+            return "dummy-crumb";
+        }
+
+        public static class DescriptorImpl extends CrumbIssuerDescriptor<DummyCrumbIssuer> {
+
+            DescriptorImpl() {
+                super(
+                    DummyCrumbIssuer.class.getName(),
+                    "Dummy Crumb Issuer"
+                );
+            }
+
+            @Override
+            public String getDisplayName() {
+                return "Dummy Crumb Issuer";
+            }
+        }
+    }
 }