Add a test for SQL logging config (#598)

* Add a test for SQL logging config

Verifies that SQL statements are logged by Hibernate when
configured to do so.

core/src/test/java/google/registry/persistence/transaction/JpaTestRulesSqlLoggingTest.java

@@ -0,0 +1,57 @@
+// Copyright 2020 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.persistence.transaction;
+
+import static com.google.common.truth.Truth.assertThat;
+import static google.registry.persistence.transaction.TransactionManagerFactory.jpaTm;
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import google.registry.persistence.transaction.JpaTestRules.JpaUnitTestRule;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.io.UnsupportedEncodingException;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+/** Unit test for {@link JpaTestRules.Builder#withSqlLogging()}. */
+public class JpaTestRulesSqlLoggingTest {
+
+  // Entity under test: configured to log SQL statements to Stdout.
+  @RegisterExtension
+  JpaUnitTestRule jpaRule = new JpaTestRules.Builder().withSqlLogging().buildUnitTestRule();
+
+  private PrintStream orgStdout;
+  private ByteArrayOutputStream stdoutBuffer;
+
+  @BeforeEach
+  public void beforeEach() {
+    orgStdout = System.out;
+    System.setOut(new PrintStream(stdoutBuffer = new ByteArrayOutputStream()));
+  }
+
+  @AfterEach
+  public void afterEach() {
+    System.setOut(orgStdout);
+  }
+
+  @Test
+  void sqlLog_displayed() throws UnsupportedEncodingException {
+    jpaTm()
+        .transact(() -> jpaTm().getEntityManager().createNativeQuery("select 1").getSingleResult());
+    assertThat(stdoutBuffer.toString(UTF_8.name())).contains("select 1");
+  }
+}