Motivation, or Is Light Air for me?

I develop web applications. I want my application tested before I hand it out to my customer.

I want to test the application as a whole, because that is what I hand out to my customer. I am not interested for example in testing a method on a DAO class, I want to test the relevant functionality of the complete application, from API (or user interface) down to the database. Once I have a test for the complete functionality, testing a method on a DAO becomes usually irrelevant.

Testing the whole application implies it has to be deployed in a target runtime environment as a complete WAR, partial deployment of a couple of classes cannot be used, because almost the whole WAR would have to be deployed anyway before each test, so then it is more efficient to deploy it completely at the start of tests and then run all the tests, each one assuming the application is already deployed and accessible on a given URL.

So, what will a typical test look like? It boils down to:

1. Clean up database.
2. Setup database into a known state required for the particular test.
3. Execute the tested functionality within the application.
4. Verify application output.
5. Verify database state after the functionality was executed.

Each test will start with setting up the test data. I want the test to be repeatable, so it will first delete all rows from the relevant tables, then insert rows with data that the test will operate on.
Since the algorithm is given (delete, insert), I don't want to code it all over again, I want a test tool to take care of it and only declaratively define the setup data.

I want to specify setup data in the DbUnit's "flat XML format". It's the simplest data format based on XML. It's also the most convenient one: with any average XML-aware editor it requires less typing than any other format.

Within the root <dataset/> element each sub-element declares a row in a database table. The name of the element specifies the name of the table. Attributes specify column names and their respective values:

<dataset>
  <order id="1" number="1234-567"/>
  <line_item id="1" order_id="1" quantity="10"/>
  <line_item id="2" order_id="1" quantity="30"/>
</dataset>

I want the test tool to generate an XSD from the database to support me when writing the test data by suggesting names of tables and columns. I want to configure the generation of XSD in my build, so that it is run whenever my database schema changes.

Similarly, I want the tool to verify database content after each test execution. I want to specify the data in the same format as for the setup.

For both setup and verification data definitions, I want to be able to use standard tokens, like @null, @any, @date, @time, @timestamp.

I generally use surrogate primary keys generated as a sequence number. I want to be able to verify foreign keys referencing such generated primary keys. I want to use the mechanism of variables for this purpose (see Features -> Verify for more info).

When writing tests I frequently want to use unique values, for example to verify proper mapping of attributes from user to DB and vice versa. I do not care what particular values are used, I just want to have them unique, so that I can tell from the destination values that the mapping works correctly.
I want to be able to use an @auto token to have the test tool generate a unique value for the column automatically.

This will:

1. Save me the painstaking work of specifying all the values manually and taking care that they really are unique.
2. Help me distinguish columns that drive the functionality from columns that just need to be unique but whose particular value is irrelevant for the test.

So, for example, I want to write a dataset like this:

<dataset>
  <user id="11" email="@auto" name="@auto" password="@auto" version="@auto" />
  <user_session id="21" user_id="11" started="@auto" version="@auto" />

  <user id="12" email="@auto" name="@auto" password="@auto" version="@auto" />
  <user_session id="22" user_id="12" started="@auto" version="@auto" />
</dataset>

Well, Light Air gives you all of these, and more! Continue to the next section to learn how to setup Light Air in your own project.