Added unit tests for the LoadBalancerClientFilter

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/LoadBalancerClientFilterTests.java

@@ -0,0 +1,114 @@
+package org.springframework.cloud.gateway.filter;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.cloud.client.DefaultServiceInstance;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
+import org.springframework.cloud.gateway.support.NotFoundException;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.util.UriComponentsBuilder;
+
+import java.net.URI;
+import java.util.LinkedHashSet;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.verifyZeroInteractions;
+import static org.mockito.Mockito.when;
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ORIGINAL_REQUEST_URL_ATTR;
+import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
+
+/**
+ * @author Tim Ysewyn
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class LoadBalancerClientFilterTests {
+
+	private ServerWebExchange exchange;
+
+	@Mock
+	private GatewayFilterChain chain;
+
+	@Mock
+	private LoadBalancerClient loadBalancerClient;
+
+	@InjectMocks
+	private LoadBalancerClientFilter loadBalancerClientFilter;
+
+	@Before
+	public void setup() {
+		exchange = MockServerWebExchange.from(MockServerHttpRequest.get("loadbalancerclient.org").build());
+	}
+
+	@Test
+	public void shouldNotFilterWhenGatewayRequestUrlIsMissing() {
+		loadBalancerClientFilter.filter(exchange, chain);
+
+		verify(chain).filter(exchange);
+		verifyNoMoreInteractions(chain);
+		verifyZeroInteractions(loadBalancerClient);
+	}
+
+	@Test
+	public void shouldNotFilterWhenGatewayRequestUrlSchemeIsNotLb() {
+		URI uri = UriComponentsBuilder.fromUriString("http://myservice").build().toUri();
+		exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, uri);
+
+		loadBalancerClientFilter.filter(exchange, chain);
+
+		verify(chain).filter(exchange);
+		verifyNoMoreInteractions(chain);
+		verifyZeroInteractions(loadBalancerClient);
+	}
+
+	@Test(expected = NotFoundException.class)
+	public void shouldThrowExceptionWhenNoServiceInstanceIsFound() {
+		URI uri = UriComponentsBuilder.fromUriString("lb://myservice").build().toUri();
+		exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, uri);
+
+		loadBalancerClientFilter.filter(exchange, chain);
+	}
+
+	@Test
+	public void shouldFilter() {
+		URI url = UriComponentsBuilder.fromUriString("lb://myservice").build().toUri();
+		exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, url);
+
+		ServiceInstance serviceInstance = new DefaultServiceInstance("myservice", "localhost", 8080, true);
+		when(loadBalancerClient.choose("myservice")).thenReturn(serviceInstance);
+
+		URI requestUrl = UriComponentsBuilder.fromUriString("https://localhost:8080").build().toUri();
+		when(loadBalancerClient.reconstructURI(any(ServiceInstance.class), any(URI.class))).thenReturn(requestUrl);
+
+		loadBalancerClientFilter.filter(exchange, chain);
+
+		assertThat((LinkedHashSet<URI>)exchange.getAttribute(GATEWAY_ORIGINAL_REQUEST_URL_ATTR)).contains(url);
+
+		verify(loadBalancerClient).choose("myservice");
+
+		ArgumentCaptor<URI> urlArgumentCaptor = ArgumentCaptor.forClass(URI.class);
+		verify(loadBalancerClient).reconstructURI(eq(serviceInstance), urlArgumentCaptor.capture());
+
+		URI uri = urlArgumentCaptor.getValue();
+		assertThat(uri).isNotNull();
+		assertThat(uri.toString()).isEqualTo("loadbalancerclient.org");
+
+		verifyNoMoreInteractions(loadBalancerClient);
+
+		assertThat((URI)exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR)).isEqualTo(requestUrl);
+
+		verify(chain).filter(exchange);
+		verifyNoMoreInteractions(chain);
+	}
+}