How to write TestCase for OpenJPA?

OpenJPA Unit Tests are JUnit Tests. The base JUnit TestCase

org.junit.TestCase

has been extended to facilitate common initialization steps or configuration settings required for unit testing OpenJPA. As a test developer, you should inherit your test class from one of the extended TestCases. This also helps the test you write to be integrated with OpenJPA test corpus of approximately 2000 test cases in 400 classes.
The inheritance hierarchy is:

junit.framework.TestCase
   +-- org.apache.openjpa.persistence.test.PersistenceTestCase
       +-- org.apache.openjpa.persistence.test.SingleEMFTestCase
          +-- org.apache.openjpa.persistence.test.SQLListenerTestCase

In general, SingleEMFTestCase

is a good candidate to inherit from. If your test needs to analyze or count number of SQL statements,

SQLListenerTestCase

should be your choice.

Setting up the test

A JUnit test is set up in

setUp()

method. OpenJPA TestCases augment the

setUp()

method to accept a list of arguments. In this list, you should specify:

• the domain classes used by your test
• the configuration properties that are critical to your test
• CLEAR_TABLES or DROP_TABLES : these are constants declared in the superclass which clears the rows or drops the tables altogether.

The following shows an example

setUp()

method

public void setUp() throws Exception {
    super.setUp(CLEAR_TABLES,                // clears records for domain classes
          Candidate.class, Election.class,   // registers Candidate and Election as persistence-capable entity
          "openjpa.Multithreaded", "true",   // sets configuration property as name-value pairs
          "openjpa.Log", "SQL=TRACE");       
}

Configuration of Persistence Unit

Notice that some configuration parameters can be set in the

setUp()

method of test program itself. This is recommended for properties that are important for your test. The non-critical parameters such as database connection properties (unless your test is about some specific aspect of a particular database) are better be specified in

META-INF/persistence.xml

.

Your test may specify the persistent unit via the following:

protected String getPersistenceUnitName() {
    return "test-eager-fetch";
}

Cleaning Up

Specifying

CLEAR_TABLES

or

DROP_TABLES

in the list of

setUp()

parameters helps to minimize impact of one test on another. Remember that the test you are writing will run with 2000 other tests.

A JUnit TestCase invokes

tearDown()

method on termination.

SingleEMFTestCase

ensures that

tearDown()

method deletes all rows for the domain classes involved in your test. While clear-your-own-mess helps in most situations, you may want the database records to remain for analysis especially when tests are failing. In that case, you may consider suppressing the superclass behavior of

tearDown()

by simply nullifying the method as

public void tearDown() throws Exception {
     // avoids super class to delete all records
}

Naming Convention

Name your test class and test methods with following suggestions:

• Test case must be in a separate sub-package of

  org.apache.openjpa.persistence.*"

  or

  org.apache.openjpa.persistence.jdbc.*"

• Keep the domain classes and Test cases in the same package
• Test case class names must start with "Test" e.g.

  TestEagerFetch

• Test method names start with "test" e.g.

  testUpdateHonoursForeignKeyConstraints()

  .
• Be generously descriptive with camel case e.g.

  TestEagerFetch

  or

  testFetchGroupLocking()

• avoid the obvious e.g.

  TestSelect

  or

  testQuery()

Domain classes

• Prefer annotation over XML Descriptors for O-R Mapping because that helps to colocate relevant information. Unless, of course, the test is specific about variations in behavior across annotation and XML Descriptors.

Comments

• Describe the purpose of the test on class comments
• If the test is related

ASF License