hibernate-demo/src/test/java/com/ankurm/hibernatedemo/jndi/CrossTestPollutionTest.java

package com.ankurm.hibernatedemo.jndi;

import static org.assertj.core.api.Assertions.assertThat;
import static org.junit.jupiter.api.Assertions.assertThrows;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NameAlreadyBoundException;
import org.h2.jdbcx.JdbcDataSource;
import org.junit.jupiter.api.MethodOrderer;
import org.junit.jupiter.api.Order;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestMethodOrder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Backs docs/10-mocking-jndi-datasources.md, chapter "'Name already bound' across two tests in the same JVM".
 * Simple-JNDI's {@code MemoryContextFactory}, with {@code org.osjava.sj.jndi.shared=true},
 * backs its bindings with a single JVM-wide static map (see
 * {@code JndiDataSourceResolutionTest}'s javadoc). If test A binds a name and never unbinds it,
 * test B's attempt to bind the SAME name in the SAME JVM fails with
 * {@code NameAlreadyBoundException} -- even though the two tests share no code, no fixture, no
 * Spring context. {@link MethodOrderer.OrderAnnotation} pins the order here deliberately, so the
 * pollution is forced to happen rather than left to JUnit's default (effectively random)
 * ordering.
 */
@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
class CrossTestPollutionTest {

    private static final Logger DEMO = LoggerFactory.getLogger("DEMO");
    private static final String SHARED_NAME = "jdbc/SharedAcrossTests";

    static {
        System.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.osjava.sj.MemoryContextFactory");
        System.setProperty("org.osjava.sj.jndi.shared", "true");
    }

    @Test
    @Order(1)
    void testA_bindsAName_andDeliberatelyDoesNotCleanUp() throws Exception {
        JdbcDataSource ds = new JdbcDataSource();
        ds.setURL("jdbc:h2:mem:pollution-a;DB_CLOSE_DELAY=-1");
        Context ctx = new InitialContext();
        ctx.createSubcontext("jdbc");
        ctx.bind(SHARED_NAME, ds);
        DEMO.info("testA bound {} -- no @AfterEach unbind on purpose, to force the pollution", SHARED_NAME);
        // If this assertion passes, the bind succeeded.
        assertThat(new InitialContext().lookup(SHARED_NAME)).isNotNull();
    }

    @Test
    @Order(2)
    void testB_bindingTheSameNameAgain_throwsNameAlreadyBoundException() throws Exception {
        JdbcDataSource ds2 = new JdbcDataSource();
        ds2.setURL("jdbc:h2:mem:pollution-b;DB_CLOSE_DELAY=-1");
        Context ctx = new InitialContext();

        NameAlreadyBoundException ex = assertThrows(NameAlreadyBoundException.class,
                () -> ctx.bind(SHARED_NAME, ds2));
        DEMO.info("testB's bind() of the SAME name testA left behind failed verbatim with: {}: {}",
                ex.getClass().getName(), ex.getMessage());

        // The fix: rebind() instead of bind() is idempotent for this exact failure mode --
        // it replaces whatever is there instead of throwing.
        ctx.rebind(SHARED_NAME, ds2);
        Object rebound = new InitialContext().lookup(SHARED_NAME);
        assertThat(rebound).isSameAs(ds2);
        DEMO.info("ctx.rebind() instead of ctx.bind() -- the standard fix -- succeeded: {}", rebound);
    }

    @Test
    @Order(3)
    void testC_theRealFix_isAfterEachUnbindNotRebind() throws Exception {
        // rebind() papers over the symptom but each test still leaks its binding into the next
        // one's JNDI namespace unless something cleans up. The actual fix is symmetry: whatever
        // a test binds, that same test unbinds, in @AfterEach, unconditionally.
        try {
            new InitialContext().unbind(SHARED_NAME);
            DEMO.info("cleanup: unbound {} so it does not leak into any test that runs after this class", SHARED_NAME);
        } catch (Exception e) {
            DEMO.info("cleanup: nothing to unbind ({})", e.toString());
        }
        assertThrows(javax.naming.NameNotFoundException.class,
                () -> new InitialContext().lookup(SHARED_NAME));
    }
}