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package org.kiwiproject.test.junit.jupiter;
import static org.kiwiproject.base.KiwiPreconditions.requireNotNull;
import static org.kiwiproject.base.KiwiStrings.f;
import static org.kiwiproject.test.mongo.MongoServerTests.startInMemoryMongoServer;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.MongoDatabase;
import de.bwaldvogel.mongo.MongoServer;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.junit.jupiter.api.extension.AfterAllCallback;
import org.junit.jupiter.api.extension.AfterEachCallback;
import org.junit.jupiter.api.extension.BeforeAllCallback;
import org.junit.jupiter.api.extension.ExtensionContext;
import org.kiwiproject.test.mongo.MongoServerTests;
import java.util.concurrent.ThreadLocalRandom;
/**
* A JUnit Jupiter {@link org.junit.jupiter.api.extension.Extension Extension} that starts an in-memory
* {@link MongoServer} once before all tests have run, and which shuts it down once after all tests have run.
* An alternative for testing against "real" MongoDB instances is the {@link MongoDbExtension}.
*
* By default, the in-memory test database will be dropped and re-created after each test so that each individual
* test can start with an empty database. If you need to retain the database between tests, construct an instance
* with the {@link DropTime#AFTER_ALL} option. The database will not be dropped or modified in any way before or
* after tests when this option is used. This is most useful in integration test scenarios in which tests are executed
* in a specific order and build upon the results of previous tests.
*
* This extension also creates a test database with a unique name that can be used in tests, and provides accessors
* to enable tests to obtain various objects such as the connection string, the test database name, a
* {@link MongoDatabase} for the test database, a {@link MongoClient}, and more.
*
* Usage:
*
* class MyMongoTest {
*
* {@literal @}RegisterExtension
* static final MongoServerExtension MONGO_SERVER_EXTENSION =
* new MongoServerExtension();
*
* {@literal @}Test
* void testInsert() {
* var database = MONGO_SERVER_EXTENSION.getTestDatabase();
* database.createCollection("my_collection");
* // ...
* }
* }
*
*
* @see MongoDbExtension
*/
@Slf4j
public class MongoServerExtension implements BeforeAllCallback, AfterAllCallback, AfterEachCallback {
/**
* The in-memory {@link MongoServer} instance started by this extension.
*/
@Getter
private MongoServer mongoServer;
/**
* Returns the Mongo connection string for the started {@link MongoServer}, e.g. {@code mongodb://localhost:34567}.
* It does not include the test database name, since this extension does not preclude creating other
* databases, for example a scenario in which the class under test integrates data from multiple MongoDB
* databases.
*/
@Getter
private String connectionString;
/**
* The name of the test database created by this extension.
*
* This is same across tests. Even though (by default using {@link DropTime#AFTER_EACH AFTER_EACH}) the test
* database is dropped after each test, a fresh database with the same name is immediately re-created following
* the drop.
*/
@Getter
private String testDatabaseName;
/**
* The test {@link MongoDatabase} created by this extension.
*
* When drop time is {@link DropTime#AFTER_EACH AFTER_EACH} (the default), a new instance is created after each
* test. Therefore tests should always re-initialize the database, for example in a {@code @BeforeEach} method.
*/
@Getter
private MongoDatabase testDatabase;
/**
* A {@link MongoClient} that can be used in tests. This should never be closed by tests, as this client is
* opened before all tests, and closed after all tests have executed.
*/
@Getter
private MongoClient mongoClient;
/**
* When to drop test databases.
*/
@Getter
private final DropTime dropTime;
/**
* Creates a new instance that will drop and re-create the test database after each test.
*/
public MongoServerExtension() {
this(DropTime.AFTER_EACH);
}
/**
* Creates a new instance that will drop the test database using the given {@link DropTime}.
*
* @param dropTime when to drop the test database
*/
public MongoServerExtension(DropTime dropTime) {
this.dropTime = requireNotNull(dropTime, "dropTime cannot be null");
}
/**
* When to drop the test databases. The extension default is {@link DropTime#AFTER_EACH}, so that each test has
* a fresh database to test against. You can also drop the database after all tests have been run, which can be
* useful in certain integration test scenarios with ordered tests, for example when each test is a part of an
* overall workflow.
*
* Note that because this extension uses an in-memory server, dropping and re-creating the test database after each
* test is no different than dropping before each test, so only the after each option is provided.
*/
public enum DropTime {
AFTER_EACH, AFTER_ALL
}
@Override
public void beforeAll(ExtensionContext context) {
mongoServer = startInMemoryMongoServer();
connectionString = MongoServerTests.getConnectionString(mongoServer);
testDatabaseName = generateTestDatabaseName();
mongoClient = new MongoClient(new MongoClientURI(connectionString));
testDatabase = mongoClient.getDatabase(testDatabaseName);
}
private static String generateTestDatabaseName() {
var millis = System.currentTimeMillis();
var random = ThreadLocalRandom.current().nextInt(10_000);
return f("test_db_{}_{}", millis, random);
}
@Override
public void afterEach(ExtensionContext context) throws Exception {
if (dropTime == DropTime.AFTER_EACH) {
dropAndRecreateTestDatabase();
LOG.trace("@AfterEach: Database {} was dropped and re-created", testDatabaseName);
}
}
private void dropAndRecreateTestDatabase() {
mongoClient.dropDatabase(testDatabaseName);
this.testDatabase = mongoClient.getDatabase(testDatabaseName);
}
@Override
public void afterAll(ExtensionContext context) {
LOG.trace("@AfterAll: Closing Mongo client and shutting in-memory MongoServer down");
mongoClient.close();
mongoServer.shutdownNow();
}
}