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Testing Sentinel Flow Control Mechanisms in Spring Cloud Alibaba

This test suite validates the flow control functionality in Spring Cloud Alibaba’s Sentinel component, focusing on triggered and non-triggered flow control scenarios. The tests verify the behavior of fallback mechanisms and response handling under different flow control conditions.

Test Coverage Overview

The test suite provides comprehensive coverage of Sentinel’s flow control mechanisms:

Verification of normal flow when control limits are not triggered
Validation of fallback behavior when flow control thresholds are exceeded
Testing of response handling across multiple consecutive requests
Integration with Spring Boot’s test framework for HTTP endpoint testing

Implementation Analysis

The testing approach utilizes Spring Boot’s TestRestTemplate for HTTP request simulation and JUnit Jupiter for test execution. The implementation follows a behavior-driven pattern, explicitly testing both positive and negative flow control scenarios with clear separation of concerns.

Uses @SpringBootTest with RANDOM_PORT configuration
Implements repeated request patterns to validate flow control behavior
Leverages AssertJ for fluent assertions

Technical Details

JUnit Jupiter test framework
Spring Boot Test framework with TestRestTemplate
LocalServerPort for dynamic port allocation
AssertJ assertion library
ArrayList for result collection
ResponseEntity for HTTP response handling

Best Practices Demonstrated

The test suite exemplifies several testing best practices in Spring Cloud applications:

Clear test method naming that describes the scenario being tested
Isolation of test scenarios for triggered and non-triggered conditions
Proper use of Spring Boot test annotations and configurations
Effective use of assertion libraries for result validation
Consistent test structure and organization

alibaba/spring-cloud-alibaba

spring-cloud-alibaba-tests/sentinel-tests/sentinel-flowcontrol-test/src/test/java/com/alibaba/cloud/tests/sentinel/degrade/SentinelFlowControlTestAppTest.java

            
/*
 * Copyright 2013-2023 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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package com.alibaba.cloud.tests.sentinel.degrade;

import java.util.ArrayList;
import java.util.List;

import org.junit.jupiter.api.Test;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.web.client.TestRestTemplate;
import org.springframework.boot.test.web.server.LocalServerPort;
import org.springframework.http.ResponseEntity;

import static com.alibaba.cloud.tests.sentinel.degrade.Util.FLOW_CONTROL_NOT_TRIGGERED;
import static com.alibaba.cloud.tests.sentinel.degrade.Util.FLOW_CONTROL_TRIGGERED;
import static org.assertj.core.api.Assertions.assertThat;
import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;

@SpringBootTest(webEnvironment = RANDOM_PORT)
class SentinelFlowControlTestAppTest {

	@LocalServerPort
	int port;

	@Autowired
	TestRestTemplate rest;

	@Test
	void testFlowControl_whenNotTriggered() {
		final int count = 3;
		List<String> result = new ArrayList<>();

		for (int i = 0; i < count; i++) {
			ResponseEntity<String> res = rest.getForEntity(
					"http://localhost:" + port + FLOW_CONTROL_NOT_TRIGGERED,
					String.class);
			result.add(res.getBody());
		}

		assertThat(result).doesNotContain("fallback");
	}

	@Test
	void testFlowControl_whenTriggered() {
		final int count = 3;
		List<String> result = new ArrayList<>();

		for (int i = 0; i < count; i++) {
			ResponseEntity<String> res = rest.getForEntity(
					"http://localhost:" + port + FLOW_CONTROL_TRIGGERED, String.class);
			result.add(res.getBody());
		}

		assertThat(result).containsSequence("fallback");
	}

}