package com.company.sales;

import com.haulmont.cuba.testsupport.TestContainer;

import java.util.ArrayList;
import java.util.Arrays;

public class SalesTestContainer extends TestContainer {

    public SalesTestContainer() {
        super();
        appComponents = new ArrayList<>(Arrays.asList(
                "com.haulmont.cuba"
                // add CUBA premium add-ons here
                // "com.haulmont.bpm",
                // "com.haulmont.charts",
                // "com.haulmont.fts",
                // "com.haulmont.reports",
                // and custom app components if any
        ));
        appPropertiesFiles = Arrays.asList(
                // List the files defined in your web.xml
                // in appPropertiesConfig context parameter of the core module
                "com/company/sales/app.properties",
                // Add this file which is located in CUBA and defines some properties
                // specifically for test environment. You can replace it with your own
                // or add another one in the end.
                "com/haulmont/cuba/testsupport/test-app.properties");
        initDbProperties();
    }

    private void initDbProperties() {
        dbDriver = "org.postgresql.Driver";
        dbUrl = "jdbc:postgresql://localhost/sales_test";
        dbUser = "cuba";
        dbPassword = "cuba";
    }

    public static class Common extends SalesTestContainer {

        // A common singleton instance of the test container which is initialized once for all tests
        public static final SalesTestContainer.Common INSTANCE = new SalesTestContainer.Common();

        private static volatile boolean initialized;

        private Common() {
        }

        @Override
        public void before() throws Throwable {
            if (!initialized) {
                super.before();
                initialized = true;
            }
            setupContext();
        }

        @Override
        public void after() {
            cleanupContext();
            // never stops - do not call super
        }
    }
}

cuba.webContextName = app-core
sales.someProperty = someValue

configure(coreModule) {
...
    task createTestDb(dependsOn: assemble, description: 'Creates local Postgres database for tests', type: CubaDbCreation) {
        dbms = 'postgres'
        dbName = 'sales_test'
        dbUser = 'cuba'
        dbPassword = 'cuba'
    }

package com.company.sales;

import com.company.sales.entity.Customer;
import com.haulmont.cuba.core.global.*;
import org.junit.Before;
import org.junit.ClassRule;
import org.junit.Test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;

public class CustomerTest {

    // Using the common singleton instance of the test container which is initialized once for all tests
    @ClassRule
    public static SalesTestContainer cont = SalesTestContainer.Common.INSTANCE;

    private Metadata metadata;

    @Before
    public void setUp() throws Exception {
        metadata = cont.metadata();
    }

    @Test
    public void testCreateCustomer() throws Exception {
        // Get a managed bean (or service) from container
        DataManager dataManager = AppBeans.get(DataManager.class);

        // Create new Customer
        Customer customer = metadata.create(Customer.class);
        customer.setName("Test customer");

        // Save the customer to the database
        dataManager.commit(customer);

        // Load the customer by ID
        Customer loaded = dataManager.load(
                LoadContext.create(Customer.class).setId(customer.getId()).setView(View.LOCAL));

        assertNotNull(loaded);
        assertEquals(customer.getName(), loaded.getName());

        // Remove the customer
        dataManager.remove(loaded);
    }
}