Makes test more general

Author: spencergibb

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/factory/SpringCloudCircuitBreakerFilterFactoryTests.java

@@ -22,6 +22,7 @@
 import org.springframework.cloud.gateway.test.BaseWebClientTests;
 import org.springframework.http.HttpStatus;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 
 /**
@@ -154,11 +155,11 @@ public void filterErrorPage() {
 			.is5xxServerError()
 			.expectBody()
 			.jsonPath("$.status")
-			.isEqualTo(504)
+			.value(status -> assertThat(HttpStatus.valueOf((Integer) status).is5xxServerError()).isTrue())
 			.jsonPath("$.message")
 			.isNotEmpty()
 			.jsonPath("$.error")
-			.isEqualTo("Gateway Timeout");
+			.isNotEmpty();
 	}
 
 	@Test