Merge pull request #132 from basil/portReuse

Allow port reuse in RestartableJenkinsRule

src/main/java/org/jvnet/hudson/test/JenkinsRule.java

@@ -693,8 +693,11 @@ public Thread newThread(Runnable r) {
         // use a bigger buffer as Stapler traces can get pretty large on deeply nested URL
         config.setRequestHeaderSize(12 * 1024);
         connector.setHost("localhost");
-        if (System.getProperty("port")!=null)
+        if (System.getProperty("port") != null) {
             connector.setPort(Integer.parseInt(System.getProperty("port")));
+        } else if (localPort != 0) {
+            connector.setPort(localPort);
+        }
 
         server.addConnector(connector);
         server.start();

src/main/java/org/jvnet/hudson/test/RestartableJenkinsRule.java

@@ -10,6 +10,8 @@
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.net.ServerSocket;
 import java.nio.file.FileVisitResult;
 import java.nio.file.Files;
 import java.nio.file.LinkOption;
@@ -62,8 +64,38 @@ public class RestartableJenkinsRule implements MethodRule {
      */
     public File home;
 
+    /**
+     * TCP/IP port that the server is listening on.
+     */
+    private final int port;
+
     private static final Logger LOGGER = Logger.getLogger(HudsonTestCase.class.getName());
 
+    public static class Builder {
+        private int port;
+
+        public Builder() {
+            this.port = 0;
+        }
+
+        public Builder withReusedPort() {
+            this.port = getRandomPort();
+            return this;
+        }
+
+        public RestartableJenkinsRule build() {
+            return new RestartableJenkinsRule(this.port);
+        }
+    }
+
+    public RestartableJenkinsRule() {
+        this.port = 0;
+    }
+
+    private RestartableJenkinsRule(int port) {
+        this.port = port;
+    }
+
     @Override
     public Statement apply(final Statement base, FrameworkMethod method, Object target) {
         this.description = Description.createTestDescription(
@@ -279,7 +311,18 @@ private void run() throws Throwable {
     }
 
     protected JenkinsRule createJenkinsRule(Description description) {
-        return new JenkinsRule();
+        JenkinsRule result = new JenkinsRule();
+        if (port != 0) {
+            result.localPort = port;
+        }
+        return result;
     }
 
+    private static synchronized int getRandomPort() {
+        try (ServerSocket s = new ServerSocket(0)) {
+            return s.getLocalPort();
+        } catch (IOException e) {
+            throw new UncheckedIOException("Unable to find free port", e);
+        }
+    }
 }

src/test/java/org/jvnet/hudson/test/RestartableJenkinsRuleTest.java

@@ -0,0 +1,55 @@
+package org.jvnet.hudson.test;
+
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assume.assumeThat;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class RestartableJenkinsRuleTest {
+
+    @Rule public RestartableJenkinsRule noPortReuse = new RestartableJenkinsRule();
+
+    @Rule
+    public RestartableJenkinsRule portReuse =
+            new RestartableJenkinsRule.Builder().withReusedPort().build();
+
+    @Test
+    public void testNoPortReuse() throws Exception {
+        assumeThat(
+                "This test requires a custom port to not be set.",
+                System.getProperty("port"),
+                nullValue());
+
+        AtomicInteger port = new AtomicInteger();
+        noPortReuse.then(
+                s -> {
+                    port.set(noPortReuse.j.getURL().getPort());
+                });
+        noPortReuse.then(
+                s -> {
+                    assertNotEquals(port.get(), noPortReuse.j.getURL().getPort());
+                });
+    }
+
+    @Test
+    public void testPortReuse() throws Exception {
+        assumeThat(
+                "This test requires a custom port to not be set.",
+                System.getProperty("port"),
+                nullValue());
+
+        AtomicInteger port = new AtomicInteger();
+        portReuse.then(
+                s -> {
+                    port.set(portReuse.j.getURL().getPort());
+                });
+        portReuse.then(
+                s -> {
+                    assertEquals(port.get(), portReuse.j.getURL().getPort());
+                });
+    }
+}