How should unit tests set up data sources when not running in an application server?

Question

Thank you all for your help. A number of you posted (as I should have expected) answers indicating my whole approach was wrong, or that low-level code should never have to know whether or not it is running in a container. I would tend to agree. However, I'm dealing with a complex legacy application and do not have the option of doing a major refactoring for the current problem.

Let me step back and ask the question the motivated my original question.

I have a legacy application running under JBoss, and have made some modifications to lower-level code. I have created a unit test for my modification. In order to run the test, I need to connect to a database.

The legacy code gets the data source this way:

(jndiName is a defined string)

Context ctx = new InitialContext();
DataSource dataSource = (DataSource) ctx.lookup(jndiName);

My problem is that when I run this code under unit test, the Context has no data sources defined. My solution to this was to try to see if I'm running under the application server and, if not, create the test DataSource and return it. If I am running under the app server, then I use the code above.

So, my real question is: What is the correct way to do this? Is there some approved way the unit test can set up the context to return the appropriate data source so that the code under test doesn't need to be aware of where it's running?

---

For Context: MY ORIGINAL QUESTION:

I have some Java code that needs to know whether or not it is running under JBoss. Is there a canonical way for code to tell whether it is running in a container?

My first approach was developed through experimention and consists of getting the initial context and testing that it can look up certain values.

private boolean isRunningUnderJBoss(Context ctx) {
        boolean runningUnderJBoss = false;
        try {
            // The following invokes a naming exception when not running under
            // JBoss.
            ctx.getNameInNamespace();

            // The URL packages must contain the string "jboss".
            String urlPackages = (String) ctx.lookup("java.naming.factory.url.pkgs");
            if ((urlPackages != null) && (urlPackages.toUpperCase().contains("JBOSS"))) {
                runningUnderJBoss = true;
            }
        } catch (Exception e) {
            // If we get there, we are not under JBoss
            runningUnderJBoss = false;
        }
        return runningUnderJBoss;
    }

Context ctx = new InitialContext();
if (isRunningUnderJboss(ctx)
{
.........

Now, this seems to work, but it feels like a hack. What is the "correct" way to do this? Ideally, I'd like a way that would work with a variety of application servers, not just JBoss.

Answer 1

The whole concept is back to front. Lower level code should not be doing this sort of testing. If you need a different implementation pass it down at a relevant point.