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Awesome Open Source

OpenTable Embedded PostgreSQL Component

Allows embedding PostgreSQL into Java application code with no external dependencies. Excellent for allowing you to unit test with a "real" Postgres without requiring end users to install and set up a database cluster.

Build Status

Basic Usage

In your JUnit test just add:

public SingleInstancePostgresRule pg = EmbeddedPostgresRules.singleInstance();

This simply has JUnit manage an instance of EmbeddedPostgres (start, stop). You can then use this to get a DataSource with: pg.getEmbeddedPostgres().getPostgresDatabase();

Additionally you may use the EmbeddedPostgres class directly by manually starting and stopping the instance; see EmbeddedPostgresTest for an example.

Default username/password is: postgres/postgres and the default database is 'postgres'

Migrators (Flyway or Liquibase)

You can easily integrate Flyway or Liquibase database schema migration:

public PreparedDbRule db =
public PreparedDbRule db = 

This will create an independent database for every test with the given schema loaded from the classpath. Database templates are used so the time cost is relatively small, given the superior isolation truly independent databases gives you.

Postgres version

The JAR file contains bundled version of Postgres. You can pass different Postgres version by implementing PgBinaryResolver.


class ClasspathBinaryResolver implements PgBinaryResolver {
    public InputStream getPgBinary(String system, String machineHardware) throws IOException {
        ClassPathResource resource = new ClassPathResource(format("postgresql-%s-%s.txz", system, machineHardware));
        return resource.getInputStream();

            .setPgBinaryResolver(new ClasspathBinaryResolver())


If you experience difficulty running otj-pg-embedded tests on Windows, make sure you've installed the appropriate MFC redistributables.

Copyright (C) 2017 OpenTable, Inc

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