Wednesday, October 3, 2012

Metaautomation and the Death of Test, part 1: No Actually, you need Test

There’s a meme going around, mostly out of Google it seems, that “Test is Dead.”

The prototypical example of this is gmail. The special SDLC (software development lifecycle) of gmail, for purposes of this meme, goes like this: devs write some feature. Devs do unit testing and some E2E testing, check in, and move on. The code is deployed to live on some (not all) web servers on the farm. End-users notice issues, end users have nothing else to do so they use the “Report a bug” control on the page to send a bug back to Google, Google receives the bug and the report is well-written with sufficient detail, but not too much, so the bug can be prioritized and potentially fixed. Tada! Testing has been outsourced to customers.

… except that the conditions that must be true for such a scenario to work tightly limit the applicability of this technique. See for example this link, which discusses the security implications of this approach: The end-users must know exactly what to expect from whatever product it is, and they’re not going to read a manual or requirements spec, so the functionality must be a reworking of some well-known idea, say, an in-browser email client or an online game of checkers. No automation is available, so regressions might go undetected for a while and be more expensive to fix than otherwise, and fixing the regression might even break the feature set with code changes that causes the regression in the first place. Clearly, this technique is much too risky for important or mission-critical data e.g. financial or medical data.

But, there’s one idea here that does work and is worth elaborating: devs are accountable to do some degree of E2E testing.

Why is E2E testing important for devs? Can’t they just toss code over the wall, after unit tests pass, and let testers deal with it? After all, that’s their job… but testers have better things to do, which is the topic of part 2 

Imagine if dev implements a feature, sees that unit tests pass, thinks “good enough” and checks it in. Assume that E2E tests are not written for this feature, because hey, it’s a brand-new feature. Build of the product in the repository succeeds. (Assume the team is not doing branch development.) Whoever tests that build first finds some issues, and writes bugs, and puts them on the developer’s plate. The dev eventually sees the bugs, theatrically slaps his/her own forehead, repros the bug and with minimal research, fixes it. If the bug isn’t tended to for a week, this is even more expensive because the code associated with the bug might not be so familiar to the dev, so it would require more research to fix the issue.

It would be MUCH better if the dev tested out the feature first with some E2E scenarios, before the checkin, or have the tester take the changeset (using Visual Studio’s TFS, this is a “shelf set”) and do some testing of the changes, to find the issues before checkin. Why better? Because a) the fix will be quicker to do b) no need to enter bugs for the record, and c) nobody need be hindered by the broken functionality of the issues, because they’re never checked in. Oh, and d) triage doesn’t have to look at the bugs, because there aren’t any reported bugs.

Another useful way to address this is to check in tests for the feature at the same time that the feature is checked in, which means that whoever wrote the E2E tests (probably a tester) combines that changeset with the product feature change. This can save a lot of churn, and the symmetry of checkin in the combined feature and quality tests looks simple and robust. The problem is if the feature automation is not ready when the feature is, and checkin of the feature would be held back. That might slow the dev down and for a complex product, there are likely other stakeholders (dev, test, and PMs) waiting on the changes, so the cost of waiting must be compared to the value of doing a unified dev + test checkin.

Therefore, the dev should be expected by team convention to do some amount of E2E testing of a new feature. How much?

For simplicity of argument, assume for the moment that nobody from Test is involved before checkin.

Too little testing on the dev’s part, and the dev won’t find his/her obvious, blocking bugs. (“Blocking” means that functionality is broken and breaks a scenario or two around the new feature, so some testing and other use of the product is blocked.) Too much, and the feature is delayed, along with other features and other work that depends on the feature.

I asked this question – how much testing by the devs? – of James Whittaker, when he gave a talk last month at SASQAG in Bellevue, Washington.

(Inline references: James’ blog is here SASQAG is here )

James’ answer was that it depends on the dev’s reputation for quality. Fair enough, but I’d prefer to start out with formal, uniform expectations and relax them for individuals as they earn the team’s trust:

First, have the test team define repeatable E2E test cases for the new feature being implemented. These test cases are to be used through the SDLC and beyond, so might as well write them earlier in the cycle than they normally are. Give the test cases sufficient detail that anybody who knows the product can run them, and precise enough that distinct bugs are always correlated with different test cases.

Then, have the devs execute the test cases when they think the feature is ready. If the feature is non-GUI (e.g. an SDK API) then maybe the E2E test can be implemented easily too, and the test run that way, before checkin and then afterwards for regression. If it’s a GUI feature e.g. in a web browser, probably the feature can’t be automated before implementation is complete.

I recommend a minimum of two happy-path test cases, one edge case if applicable, and one negative case. It’s expected at project outset that a) a tester writes the test cases before the feature is implemented b) the dev (and maybe the tester too) runs the test cases before checkin.

This will save the whole team a lot of time, but especially the testers… for the good of the product, they should be extremely busy anyway, which is the topic of part 2 of this post. 

1 comment:

  1. Great article! My favorite quote is, "end users have nothing else to do so they use the “Report a bug” control on the page to send a bug back to Google, Google receives the bug and the report is well-written with sufficient detail, but not too much, so the bug can be prioritized and potentially fixed"


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