Fix builds hanging if server cannot start

If the server factory fails to start the test resources service, then
we'd wait indefinitely for the server port file to appear, which
causes builds to hang.

Closes #785

test-resources-build-tools/src/main/java/io/micronaut/testresources/buildtools/ServerUtils.java

@@ -81,8 +81,10 @@ public class ServerUtils {
     private static final String FLAT_JAR = "flat.jar";
 
     // See io.micronaut.testresources.testcontainers.DockerSupport.TIMEOUT
-    private static final String DOCKER_CHECK_TIMEOUT_SECONDS_ENV = "TEST_RESOURCES_DOCKER_CHECK_TIMEOUT_SECONDS";
-    private static final String DOCKER_CHECK_TIMEOUT_SECONDS_PROPERTY = "docker.check.timeout.seconds";
+    private static final String DOCKER_CHECK_TIMEOUT_SECONDS_ENV =
+        "TEST_RESOURCES_DOCKER_CHECK_TIMEOUT_SECONDS";
+    private static final String DOCKER_CHECK_TIMEOUT_SECONDS_PROPERTY =
+        "docker.check.timeout.seconds";
 
     /**
      * Writes the server settings in an output directory.
@@ -335,16 +337,24 @@ private static void startAndWait(ServerFactory serverFactory,
         waitForServerToBeAvailable(serverFactory, explicitPort, portFilePath);
     }
 
-    private static void waitForServerToBeAvailable(ServerFactory serverFactory, Integer explicitPort,
-                                  Path portFilePath) {
+    private static void waitForServerToBeAvailable(ServerFactory serverFactory,
+                                                   Integer explicitPort,
+                                                   Path portFilePath) {
         Integer port = explicitPort;
         if (explicitPort == null) {
-            while (!Files.exists(portFilePath)) {
+            int retries = 4;
+            long dur = STARTUP_TIME_WAIT_MS;
+            while (--retries > 0 && !Files.exists(portFilePath)) {
                 try {
-                    serverFactory.waitFor(Duration.of(STARTUP_TIME_WAIT_MS, ChronoUnit.MILLIS));
+                    serverFactory.waitFor(Duration.of(dur, ChronoUnit.MILLIS));
                 } catch (InterruptedException e) {
                     Thread.currentThread().interrupt();
+                    break;
                 }
+                dur *= 2;
+            }
+            if (!Files.exists(portFilePath)) {
+                throw new IllegalStateException("Port file not created. Server probably failed to start.");
             }
             try {
                 port = Integer.parseInt(Files.readString(portFilePath));