Applying BDD testing to batch scenarios?

Question

I'm trying to apply BDD practices to my organization. I work in a bank where the nightly batch job is a huge orchestration multi-system flow of batch jobs running and passing data between one another.

During our tests, interactive online tests probably make up only 40-50% of test scenarios while the rest are embedded inside the batch job. As an example, the test scenario may be:

1. Given that my savings account has a balance of $100 as of 10PM
2. When the nightly batch is run at 11PM
3. Then at 3AM after the batch run is finished, I should come back and see that I have an additional accrued interest of $0.001.
4. And the general ledger of the bank should have an additional entry for accrued interest of $0.001.

So as you can see, this is an extremely asynchronous scenario. If I were to use Cucumber to trigger it, I can probably create a step definition to insert the $100 balance into the account by 10PM, but it will not be realistic to use Cucumber to trigger the batch to be run at 11PM as batch jobs are usually executed by operators using their own scheduling tools such as Control-M. And having Cucumber then wait and listen a few hours before verifying the accrued interest, I'm not sure if I'll run into a timeout or not.

This is just one scenario. Batch runs are very expensive for the bank and we always tack on as many scenarios as possible to ride on a single batch run. We also have aging scenarios where we need to run 6 months of batch just to check whether the final interest at the end of a fixed deposit term is correct or not (I definitely cannot make Cucumber wait and listen for that long, can I?)

My question is, is there any example where BDD practices were applied to large batch scenarios such as these? How would one approach this?

Edit to explain why I am not targeting to execute isolated test scenarios where I am in control:

We do isolated scenarios in one of the test levels (we call it Systems Test in my bank) and BDD indeed does work in that context. But eventually, we need to hit a test level that has an entire end-to-end environment, typically in SIT. In this environment, it is a criteria for multiple test scenarios to be run in parallel, none of which have complete control over the environment. Depending on the scope of the project, this environment may run up to 200 applications. So customer channels such as Internet Banking will run transactional scenarios, whiles at the core banking system, scenarios such as interest calculation, automatic transfers etc will be executed. There will also be accounting scenarios where a general ledger system consolidates and balances all the accounts in the environment. To do manual testing in this environment frequently requires at least 30-50 personnel executing transactions and checking on results.

What I am trying to do is to find a way to leverage on a BDD framework to automate test execution and capture the results so that we do not have to manually track them all in the environment.

Answer 1

One approach you might consider would be to have a reporting process that queries the results of each batch run. It would then store the results you were interested in (i.e. those from your tests) in to a test analysis database.

I'm assuming that each batch run has a unique identifier. This identifier would be used as the key for the test results.

Here is an example of how it might work:

• We know when the batch runs are finished (say this is at 4am). We schedule a reporting job to start after batch run completion (say at 5am) that analyses the test accounts.
• The reporting job looks at Account X and Account Y. It records the amount of money in their account in a table alongside the unique identifier for the batch run. This information is stored in a test results database.
• A separate process matches up test scenarios with test results. It knows test scenario 29 was tied to batch run ZZ20 and so goes looking in the test results database for the analysis from batch run ZZ20.
• In the morning the test engineer checks the results of the run. They see that test scenario 29 failed as there was only £100 in Account X rather than the £100.001 that was expected.

This setup would allow you to synchronously process asynchronous batch runs. It would be challenging to configure though, as you would need to do a lot of automation around reporting and linking test scenarios with test results.

Answer 2

It sounds to me as if you are not in control over the execution of the scenario.

It is obviously so that waiting for a couple of hours before validating a result is a not a great idea.

Is it possible to extract just the part of the batch that is interesting in this scenario? If that is possible, then I would not expect the execution time to 4 - 6 hours.

If it isn't possible to execute the desired functionality in isolation, then you have a problem regarding test-ability of your system. This is very common and something you really want to address. If the only way to test is to run the entire system, then you are not able to confidently say that it is working properly since all combinations that need testing are hard, sometimes even impossible, to execute.

Unfortunately, there doesn't seem to exist a quick fix. You need to be in a position where you are able to verify small parts of the system in order to verify them fast and reliably. And it doesn't matter if you are using Cucumber or any other tool to for the verification, all tools will have the same issue.