Add custom Redis wait strategy as an example and to mitigate #160

Author: rnorth

shade-test/clashing-deps-jackson/src/test/java/RedisJacksonBackedCacheTest.java

@@ -3,10 +3,12 @@
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.rnorth.ducttape.unreliables.Unreliables;
 import org.testcontainers.containers.GenericContainer;
 import redis.clients.jedis.Jedis;
 
 import java.util.Optional;
+import java.util.concurrent.TimeUnit;
 
 import static org.rnorth.visibleassertions.VisibleAssertions.*;
 
@@ -17,7 +19,8 @@ public class RedisJacksonBackedCacheTest {
 
     @Rule
     public GenericContainer redis = new GenericContainer("redis:3.0.6")
-                                            .withExposedPorts(6379);
+            .withExposedPorts(6379)
+            .waitingFor(new RedisWaitStrategy());
     private Cache cache;
 
     @Before
@@ -33,10 +36,10 @@ public void testFindingAnInsertedValue() {
         Optional<String> foundObject = cache.get("foo", String.class);
 
         assertTrue("When an object in the cache is retrieved, it can be found",
-                        foundObject.isPresent());
+                foundObject.isPresent());
         assertEquals("When we put a String in to the cache and retrieve it, the value is the same",
-                        "FOO",
-                        foundObject.get());
+                "FOO",
+                foundObject.get());
     }
 
     @Test
@@ -46,4 +49,16 @@ public void testNotFindingAValueThatWasNotInserted() {
         assertFalse("When an object that's not in the cache is retrieved, nothing is found",
                 foundObject.isPresent());
     }
+
+    private class RedisWaitStrategy extends GenericContainer.AbstractWaitStrategy {
+        @Override
+        protected void waitUntilReady() {
+            //noinspection LoopStatementThatDoesntLoop
+            Unreliables.retryUntilSuccess(10, TimeUnit.SECONDS, () ->
+            {
+                Jedis jedis = new Jedis(redis.getContainerIpAddress(), redis.getMappedPort(6379));
+                return jedis.ping();
+            });
+        }
+    }
 }