retroredge / sql-unit-testing-sandbox

Java / H2 Database unit testing demonstration / PoC

SQL unit testing sandbox

This project demonstrates how Java unit tests and an in-memory H2 database (https://www.h2database.com/) can be used to run some basic unit tests against DLL and SQL scripts.

To run the tests

./mvnw clean test

Any syntax errors in the DDL or SQL scripts will be picked up by the unit test which also asserts that the transformation has joined the data from the two tables as expected.

The unit test TransformationTest.java is a pure Java unit test that uses the JDBC API to perform the database operations.

The H2 in-memory database JDBC URL used in the Java test is:

jdbc:h2:mem:testdb

The unit test TransformationSpec.groovy is a Groovy Spock unit test that is functionally equivalent to the Java unit test but demonstrates the more concise syntax of the Groovy SQL DSL and the Spock testing DSL.

The H2 in-memory database JDBC URL used in the Groovy Spock test is:

jdbc:h2:mem:testspockdb

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H2 console access

If you wish to examine the data created by the tests using the H2 console you will need to modify the H2 URL to be a file based JDBC URL:

jdbc:h2:~/testdb

or

jdbc:h2:~/testspockdb

Then launch the console as follows.

1. Locate the H2 JARs. For example:

cd ~/.m2/repository/com/h2database/h2/2.1.214

2. Run this command to launch the console:

java -jar h2*.jar

A new browser tab should launch at: http://localhost:8082/ displaying the H2 console

3. Use this JDBC URL in the console to connect to the file based database that the tests are using:

jdbc:h2:tcp://localhost/~/testdb

or

jdbc:h2:tcp://localhost/~/testspockdb

You will need to disconnect / stop the console to execute the unit tests again