ADD: failing testcases for executeBatch() on SqlUpdate

Signed-off-by: Jonas Pöhler (JPo) <jonas.poehler@foconis.de>

ebean-core/src/test/java/org/tests/update/TestSqlUpdateBatch.java

@@ -0,0 +1,65 @@
+package org.tests.update;
+
+import io.ebean.BaseTestCase;
+import io.ebean.DB;
+import io.ebean.SqlUpdate;
+import io.ebean.Transaction;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Testclass that ensures the correct behaviour of SqlUpdate in combination with batching.
+ *
+ * @author Jonas Pöhler, FOCONIS AG
+ */
+public class TestSqlUpdateBatch extends BaseTestCase {
+
+  /**
+   * This test ensures the correct behaviour of update batching in the {@code BatchedPstmtHolder} after a flush. Two batch updates
+   * are executed with each a batchsize of 21, which is the default limit for automatic flushing on {@code addBatch()}. After that
+   * the statements are each executed with {@code executeBatch()}. The desired behaviour is, that each execution succeeds although
+   * technically the batch was already flushed.
+   */
+  @Test
+  public void testTwoParallelBatches() {
+    try (Transaction txn = DB.beginTransaction()) {
+      // Dummy updates, that effectively do nothing, but ebean doesn't need to know this.
+      final SqlUpdate update = DB.sqlUpdate("update uuone set name = ? where 0=1");
+      final SqlUpdate delete = DB.sqlUpdate("delete from uuone where ?=-1");
+
+      for (int i = 0; i <= 20; i++) {
+        update
+          .setParameter(1, String.valueOf(i))
+          .addBatch();
+        delete
+          .setParameter(1, String.valueOf(i))
+          .addBatch();
+      }
+
+      delete.executeBatch();
+      update.executeBatch();
+    }
+  }
+
+  /**
+   * This test checks that for a batch update a correct array with update counts is returned. If a update with 40 entries is
+   * executed, it is expected, that {@code executeBatch()} returns a array with 40 elements each containing the update count for
+   * the given parameters.
+   */
+  @Test
+  public void testBatchReturnArrayLength() {
+    try (Transaction txn = DB.beginTransaction()) {
+      // Dummy update, that effectively does nothing, but ebean doesn't need to know this.
+      final SqlUpdate update = DB.sqlUpdate("update uuone set name = ? where 0=1");
+
+      for (int i = 0; i <= 40; i++) {
+        update
+          .setParameter(1, String.valueOf(i))
+          .addBatch();
+      }
+      assertEquals(40, update.executeBatch().length);
+    }
+  }
+
+}