Adding scheam registry samples

* Add plain vanilla schema registry sammples using ScSt schema registry server
 * Add samples using Confluent schema registry
 * Add acceptance tests for the plain vanilla examples

samples-acceptance-tests/src/test/java/sample/acceptance/tests/AbstractSampleTests.java

@@ -0,0 +1,51 @@
+package sample.acceptance.tests;
+
+import org.assertj.core.util.Files;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.util.StringUtils;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.util.stream.Stream;
+
+import static org.junit.Assert.fail;
+
+/**
+ * @author Soby Chacko
+ */
+public abstract class AbstractSampleTests {
+
+	private static final Logger logger = LoggerFactory.getLogger(AbstractSampleTests.class);
+
+	protected boolean waitForLogEntryInFile(String app, File f, String... entries) {
+		logger.info("Looking for '" + StringUtils.arrayToCommaDelimitedString(entries) + "' in logfile for " + app);
+		long timeout = System.currentTimeMillis() + (60 * 1000);
+		boolean exists = false;
+		while (!exists && System.currentTimeMillis() < timeout) {
+			try {
+				Thread.sleep(2 * 1000);
+			} catch (InterruptedException e) {
+				Thread.currentThread().interrupt();
+				throw new IllegalStateException(e.getMessage(), e);
+			}
+			logger.info("Polling to get log file. Remaining poll time = "
+					+ (timeout - System.currentTimeMillis() + " ms."));
+			String log = Files.contentOf(f, StandardCharsets.UTF_8);
+
+			if (log != null) {
+				if (Stream.of(entries).allMatch(log::contains)) {
+					exists = true;
+				}
+			}
+		}
+		if (exists) {
+			logger.info("Matched all '" + StringUtils.arrayToCommaDelimitedString(entries) + "' in logfile for app " + app);
+		} else {
+			logger.error("ERROR: Couldn't find all '" + StringUtils.arrayToCommaDelimitedString(entries) + "' in logfile for " + app);
+			fail("Could not find the test data in the logs");
+		}
+		return true;
+	}
+
+}