Automation-assisted technical debt retirement

Last updated on March 17th, 2020 at 12:58 pm

When we transform assets to retire some of the technical debt they carry, service disruptions are sometimes necessary. To minimize service disruptions while technical debt retirement efforts are underway, it’s advantageous to automate some procedures. Automation-assisted technical debt retirement provides two important benefits: reduced disruption of operations and reduced incidence of errors.

I’m using the concept of automation a bit loosely here. I don’t mean to imply that these procedures are autonomous. What I mean is that engineers have available tools for performing many operations with a minimum of thought. For example, in this sense of automated, an engineer can issue a command such as, “Test Module Alpha Using Test Suite Delta.” That command executes a predefined set of tests. Following execution, the appropriate engineers receive the results. The tool also archives those results appropriately. If the results are anomalous, engineers can then take appropriate action.

Benefits of automation-assisted technical debt retirement

Collapse of the I-35W bridge in Minneapolis, Minnesota
The I-35W Bridge collapse, day 4, Minneapolis, Minnesota, August 5, 2007. The proximate cause of the collapse was underweight gusset plate design, which made the bridge vulnerable to the increased static load due to concrete road surfacing additions over the years, and to the weight of construction equipment and supplies during a repair project that was then underway [NTSB 2008].
When we conduct maintenance or technical debt retirement projects involving assets that must remain operational during project execution, we risk stressing the asset in ways that extend beyond its safe operation envelope. The National Transportation Safety Board found that this occurred in the case of the I-35W bridge collapse. These effects are more difficult to imagine in software systems, but they can occur when we shift load from the systems undergoing modification to other systems. Those load-bearing systems can then become overloaded. Or these effects can occur when we shift load not from one asset to another, but from one time window to another on the same asset. The result can be high loads in some time windows.
Photo by Kevin Rofidal, United States Coast Guard, courtesy Wikimedia Commons.
The more obvious benefit of automated procedures is speed. For example, an asset removed from service for testing can be returned to service more quickly if the testing is automated. And if trouble erupts during operations of a newly transformed asset, engineers can swap the untransformed asset back into place quickly. So-called roll-out and roll-back tools are just a few of the many elements of a set of practices collectively known as continuous delivery [Humble 2010].

The second benefit of this kind of automation is error avoidance. For example, inconsistent or incomplete testing can fail to find errors and defects, and that leads to rework and further disruptions. Performing tests incorrectly, finding “defects” that aren’t there, is another way to generate trouble. Automated procedures are much less prone to error if we maintain, test, and certify them periodically. For example, consider subjecting a module to a particular test suite. With automation assistance, engineers needn’t remember (or take time to look up) how to prepare the asset for tests. They  needn’t remember (or take time to look up) how to run the tests, or what the members of the test suite are. Long advocated as an essential element of sound engineering practice, test automation can avoid some of these problems. But it’s far short of a panacea [Bach 1999].

Other automation opportunities

In some situations, we can automate debt retirement itself. When we can retire instances of the technical debt in question by performing an automated transformation on an asset, the transformation is faster and more reliable.

A most important practice associated with automation-assisted technical debt retirement is automation-assisted regression testing. Investments in thorough and focused regression testing have potentially shockingly high returns in the debt retirement context. They can be just as valuable during development and routine maintenance.

To perform a regression test on an asset that has undergone a change is to examine its behavior under a specified set of conditions. Such investigations can determine whether those changes caused the asset to misbehave. So a regression test determines whether the asset has regressed as a result of the change. Automated or automation-assisted regression tests help the project team detect problems in assets that they’ve transformed. And that’s much better than having the business units that depend on those assets encounter problems during operations [Ge 2014].

Many of these same regression tests can also be useful during enhancement and ongoing maintenance of the asset. Often, investing in automated regression tests in advance of the debt retirement project can enhance development and maintenance performance relative to those assets. Later, when the debt retirement project begins, the previously obtained results of regression tests will already be available.

Last words

For some debt retirement projects, specially created automated regression tests might be beneficial. Assign engineers to continual automation tool development for debt retirement projects. That’s probably the best way to support these needs.

These automation capabilities are unlikely to be available commercially, because they’re so specialized to the asset being tested. Because general applicability is unnecessary, building them in-house is both practical and economical.  If people with the necessary skills are unavailable, acquire them . We can justify these investments economically if we take into account the savings from reduced service disruptions for debt-bearing assets.

References

[Bach 1999] James Bach. “Test Automation Snake Oil!” (1999).

Available: here; Retrieved: January 2, 2019

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[Ge 2014] Xi Ge and Emerson Murphy-Hill. “Manual Refactoring Changes with Automated Refactoring Validation,” Proceedings of the 36th International Conference on Software Engineering. ACM, 2014.

Available: here; Retrieved: January 1, 2019

Cited in:

[Humble 2010] Jez Humble and David Farley. Continuous delivery: reliable software releases through build, test, and deployment automation, Pearson Education, 2010.

Cited in:

[NTSB 2008] National Transportation Safety Board. “Board Meeting Executive Summary: Collapse of I-35W Highway Bridge, Minneapolis, Minnesota, August 1, 2007,”, November 13, 2008.

Available: here; Retrieved: January 3, 2019.

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