ZOOKEEPER-3276: Make X509UtilTest.testCreateSSLServerSocketWithPort less flaky

Pick the free port right before using it, so there is less time for another thread/process to grab it from under us.

Author: Ilya Maykov <[email protected]>

Reviewers: [email protected]

Closes apache#816 from ivmaykov/ZOOKEEPER-3276

Author: ivmaykov

zookeeper-server/src/test/java/org/apache/zookeeper/common/X509UtilTest.java

@@ -192,8 +192,8 @@ public void testCreateSSLServerSocketWithoutPort() throws Exception {
 
     @Test(timeout = 5000)
     public void testCreateSSLServerSocketWithPort() throws Exception {
-        int port = PortAssignment.unique();
         setCustomCipherSuites();
+        int port = PortAssignment.unique();
         SSLServerSocket sslServerSocket = x509Util.createSSLServerSocket(port);
         Assert.assertEquals(sslServerSocket.getLocalPort(), port);
         Assert.assertArrayEquals(customCipherSuites, sslServerSocket.getEnabledCipherSuites());