client: fix concurrency issue in test

Stop the spider only after the access to the seed URL occurred and
verify that the new URL was not accessed, otherwise the test could fail
because the seed URL could be accessed between the calls to start and
stop.

Signed-off-by: thc202 <thc202@gmail.com>

addOns/client/src/test/java/org/zaproxy/addon/client/spider/ClientSpiderUnitTest.java

@@ -26,13 +26,16 @@
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.CALLS_REAL_METHODS;
 import static org.mockito.Mockito.atLeastOnce;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 import static org.mockito.Mockito.withSettings;
 
 import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -119,27 +122,34 @@ void shouldRequestInScopeUrls() {
     }
 
     @Test
-    void shouldIgnoreRequestAfterStopped() {
+    void shouldIgnoreRequestAfterStopped() throws Exception {
         // Given
-        ClientSpider spider =
-                new ClientSpider(extClient, "https://www.example.com/", clientOptions, 1);
+        CountDownLatch cdl = new CountDownLatch(1);
+        String seedUrl = "https://www.example.com/";
+        ClientSpider spider = new ClientSpider(extClient, seedUrl, clientOptions, 1);
         Options options = mock(Options.class);
         Timeouts timeouts = mock(Timeouts.class, withSettings().defaultAnswer(CALLS_REAL_METHODS));
         when(wd.manage()).thenReturn(options);
         when(options.timeouts()).thenReturn(timeouts);
+        String urlAfterStop = "https://www.example.com/test#1";
+        doAnswer(
+                        invocation -> {
+                            spider.stop();
+                            map.getOrAddNode(urlAfterStop, false, false);
+                            cdl.countDown();
+                            return null;
+                        })
+                .when(wd)
+                .get(seedUrl);
 
         // When
         spider.start();
-        spider.stop();
-        map.getOrAddNode("https://www.example.com/test#1", false, false);
-        try {
-            Thread.sleep(200);
-        } catch (InterruptedException e) {
-            // Ignore
-        }
+        // and stopped on URL access
 
         // Then
-        verify(wd, never()).get(any());
+        cdl.await(2, TimeUnit.SECONDS);
+        assertThat(spider.isStopped(), is(true));
+        verify(wd, never()).get(urlAfterStop);
     }
 
     @Test