Correctly deflake MavenPluginTest (#2165)

The prior attempt to fix the code was still flaky as the second click
could also be intercepted by the chevron.

Be more robust against the chevron clicking being intercepted by trying
until the element is stale.

Author: jtnord

src/test/java/plugins/MavenPluginTest.java

@@ -28,6 +28,7 @@
 import static org.jenkinsci.test.acceptance.Matchers.pageObjectExists;
 
 import com.google.inject.Inject;
+import java.time.Duration;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.regex.Pattern;
@@ -207,15 +208,23 @@ private void assertHasModule(MavenModuleSet job, String name) {
 
         job.visit("modules");
         WebElement webElement = find(by.xpath("//a[@href='%s/']", name));
-        webElement.click();
-        // a menu pops out with how selenium clicks this, an actual user will not have an issue with this
-        // clicking a second time fixes it
-        if (!driver.getCurrentUrl().equals(job.module(name).url.toExternalForm())) {
+
+        // A selenium click will go to the center of the button.
+        // If the name is short enough (like root in some of these tests) the click will be the chevron button that flys
+        // out.
+        //
+        // To work around this we click multiple times, if the clicks are intercepted by a chevron flyout then due to
+        // the sticky element hacks they do not fly back in, so eventually one of the clicks will make!
+        waitFor(webElement).withTimeout(Duration.ofSeconds(5)).until(() -> {
             webElement.click();
-        }
+            return isStale(webElement);
+        });
+
         assertThat(driver.getCurrentUrl(), equalTo(job.module(name).url.toExternalForm()));
 
         build.open();
+        // in the build page the status icon is also within the 'a' element so the width is big enough that the center
+        // point won't be the chevron
         find(by.xpath("//a[@href='%s/']", name)).click();
         assertThat(driver.getCurrentUrl(), equalTo(build.module(name).url.toExternalForm()));
     }