How to Unit Test in MariaDB

How do I unit test stored procedures and queries in MariaDB?

Unit testing in MariaDB verifies that a single stored procedure, function, or query returns the expected result by running it against controlled data and asserting outcomes.

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Description

Example H2

Example H3

What is unit testing in MariaDB?

Unit testing in MariaDB checks one routine, view, or query at a time against a disposable data set. A failing assertion immediately signals a defect.

Why should I unit test SQL code?

Unit tests prevent regressions, document expected behaviour, and enable safe refactoring. They also integrate with CI/CD pipelines for automated feedback.

How do I create a test harness quickly?

1) Spin up a dedicated test_db schema. 2) Populate Customers, Orders, Products, and OrderItems with deterministic seed rows. 3) Add assertion helpers such as assert_equals. 4) Run tests via mariadb-test-run or any shell script that stops on a non-zero exit code.

What does an assertion helper look like?

Procedure: assert_equals

SIGNAL is raised when expected and actual values differ, instantly failing the test.

How do I write a test case?

Wrap each scenario in a stored routine whose only job is to call assertions. Use clear names such as test_discount_calculation().

How can I automate tests in CI?

Package the test schema in a Docker image, run mariadb-test-run --suite=/tests, and let your CI platform fail the build on any error.

Best practices to remember

• Isolate each test with BEGIN/ROLLBACK or disposable schemas.
• Seed minimal yet complete data.
• Keep assertion messages descriptive.
• Run tests on every pull request.

Common pitfalls to avoid

• Never rely on production data—tests must create their own.
• Reset auto-increment counters between tests to prevent key clashes.

Why How to Unit Test in MariaDB is important

How to Unit Test in MariaDB Example Usage


-- Test that get_customer_ltv() returns correct lifetime value for customer 7
CALL assert_equals(
    1234.50,
    (SELECT get_customer_ltv(7)),
    'LTV calculation failed for customer 7'
);

How to Unit Test in MariaDB Syntax


DELIMITER //
-- Assertion helper
CREATE PROCEDURE assert_equals(
    expected VARCHAR(255),
    actual   VARCHAR(255),
    msg      VARCHAR(255)
)
BEGIN
    IF expected <> actual THEN
        SIGNAL SQLSTATE '45000'
            SET MESSAGE_TEXT = msg;
    END IF;
END//

-- Example test case for Orders.total_amount
CREATE PROCEDURE test_order_total()
BEGIN
    CALL assert_equals(
        '579.90',
        (SELECT total_amount FROM Orders WHERE id = 42),
        'Order 42 total incorrect'
    );
END//

DELIMITER ;

Common Mistakes

Running tests against production data causes flaky failures and may corrupt real information. Fix by loading a fresh, minimal dataset in an isolated schema for every test run.
Forgetting to reset AUTO_INCREMENT leads to primary-key clashes across repeated runs. Wrap each test in BEGIN/ROLLBACK or truncate tables and SET @@auto_increment_increment=1 afterward.

Frequently Asked Questions (FAQs)

How do I automate MariaDB unit tests in CI?

Use Docker to spin up MariaDB, run mariadb-test-run or a custom shell script that executes all test procedures, and fail the job when any SIGNAL is raised.