Monday, January 17, 2011

Gaming Unit Test Metrics

Unit Testing is a popular buzzword - most developer jobs request it, teams want to say they have it, and most coding leaders actively endorse it. However, you won't be able to hire a team of devs who don't want to write unit tests, and then "force" them via measuring certain metrics. Developers can game metrics.

1. Metric: Code Coverage
The #1 unit testing metric is code coverage, and this is a good metric, but it's insufficient. For example, a single regular expression to validate an email could require many different tests - but a single test will give it 100% code coverage. Likewise, you could leverage a mocking framework to artificially get high code coverage by mocking out all the "real" code, and essentially having a bunch of "x = x".

2. Metric: Number of unit tests
Sure, everything being equal, 10 tests probably does more work than just 1 test, but everything is not equal. Developer style and the code-being-tested both vary. One dev may write a single test with 10 asserts, another dev may put each of those asserts in its own test. Also, you could have many tests that are useless because they're checking for the "wrong" thing or are essentially duplicates of each other.

3. Metric: % of tests passing
If you have a million LOC with merely 5 unit tests, having 100% tests passing because all 5 pass is meaningless.

4. Metric: Having X tests for every Y lines of code
A general rule of thumb is to have X unit tests (or X lines of unit testing code) for every Y lines of code. However, LOC does not indicate good code. Someone could write bloated unit test code ("copy and paste"), so this could be very misleading.

5. Metric: How long it takes for unit tests to run
"We have 5 hours of tests running, so it must be doing something!". Ignore for the moment that such long-running tests are no longer really "unit" tests, but rather integration tests. These could be taking a long time because they're redundant (loop through every of a 1 GB file), or extensively hitting external machines such that it's really testing network access to a database rather than business logic.

6. Metric: Having unit testing on the project plan
"We have unit testing as an explicit project task, so we must be getting good unit tests out of it!" Ignore for the moment that unit tests should be done hand-in-hand with development as opposed to a separate task - merely having tests as an explicit task doesn't mean it's actually going to be used for that.

7. Metric: Having high test counts on methods with high cyclometric complexity
This is useful, but it boils down to code coverage (see above) - i.e. find the method with high complexity, and then track that method's code coverage.

Obviously a combo of these metrics would drastically help track unit test progress. If you have at least N% code coverage, with X tests for every Y lines of code, and they all pass - it's better than nothing. But fundamentally the best way to get good tests is by having developers who intrinsically value unit testing, and would write the tests not because management is "forcing" them with metrics, but because unit tests are intrinsically valuable.

Saturday, January 15, 2011

Writing tip: Concise language

You are "paying" for each word, and if your idea is too expensive to communicate, it will never be heard - let alone implemented. Therefore it's imperative that developers have good writing skills if they want to become influential. One metric of good writing is that it is concise. Here is a brainstorm of tips.

Tip: Remove un-needed words and phrases

If the word adds zero value, then remove it.
//Remove "Anything about"
Anything about schemas will drive architecture.
Schema will drive architecture.

//Remove phrase "my approach"
I’ll need to confirm my approach with Bob
I’ll need to confirm with Bob

//Restructure sentence to remove the word "it"
It takes effort to ask for something.
Asking for something takes effort.
Tip: The word is implied, so you don't need it.
//Implied that you're concerned, which is why you're talking about it
My concern is that X is bad.
X is bad

//The word "something" is implied
If there’s something more to it.
If there's more to it.

//The word "about" is implied by estimate, and the number being rounded
We estimate the list to have about 10,000 rows.
We estimate the list to have 10,000 rows.

//The phrase "Ed mentioned" implies "Discussing with Ed"
Discussing with Ed yesterday, he mentioned that...
Ed mentioned yesterday that...
Tip: remove duplicate words

Sometimes people use duplicate words. Maybe because (1) they think it drives the point home, (2)
they feel like it has to be long (schools trained them to write "at least 500 words"), (3) they
can't think of a single word to describe both sub-words.
//Just pick one - either "harsh" or "ruthless"
The production environment is harsh and ruthless
The production environment is ruthless
Tip: Replace a phase with a single word
Sometimes a big phrase can be replaced with a single word because that single word is the definition of the big phrase.
//Replace the entire phrase with one word that means the same thing
The application must be able to handle an increasing amount of demand.
The application  must be scalable.
Tip: Condense two sentences into one
//Remove a descriptive sentence by applying it to the noun directly.
I'd like to set up a call. An hour should be enough time.
I'd like to set up a one-hour call.
Tip: Avoid un-needed commas
If you have a bunch of small phrases joined by multiple commas, consider restructuring it into a single sentence. Even if it doesn't make it more concise, it will probably make it easier to read.
//Remove comma
and for each line, trims it.
and trims each line.
//Merge two short sentences into 1:
We are creating a custom list. It will have 1000 rows.
We are creating a custom list containing 1000 rows.
//Restructure sentence
Yesterday, Ed mentioned that...
Ed mentioned yesterday that...
//Restructure sentence
If you approve of this design, please let me know.
Please let me know if you approve of this design.

Monday, January 10, 2011

Writing tip: Avoid abstract words

We all know that influential developers need good communication skills. I love technology, but if you can't communicate your technical ideas to your coworkers, then they won't be adopted.

You need to be concise, else people will just tune you out. One way to do that is to choose a more descriptive work that packs more meaning.  Your word count remains about the same - it's absolutely not just rambling on - but the sentence caries more meaning.

Of course sometimes you deliberately want the more abstract word, but it's good to be aware of the more-descriptive alternatives so that you can make a conscious choice of what's best for the situation.

Weak wordCommentConsider InsteadExample
Do, DoesDoes what?create, build, make, install
Bob does builds
Bob installs builds
RunWhat does the "running" do?scrubs, cleans, updates, processes, installs, configures
The service runs on the directory
The service cleans the directory
ChangeHow does it change?insert, update, delete, improves
The tool changes the file
The tool updates the file
ProcessorWhat does the process do?copier, uploader
FileProcessor tool
FileUploader tool
It, Object, ThingWhat kind of thing?C# class, SQL script, COM+ object
It runs fast.
The C# class runs fast
TalkWhat kind of talking?discussed, reasoned, concluded, negotiated, argued, explained
Bob talked about structs
Bob explained structs
IssueWhat kind of issue?bug, feature request, task, problem
This is an issue
This is an error
OtherIn what way?previous, next, remaining, bigger, smaller
I need the other node
I need the previous node
GoodIn what sense?faster, more reliable, higher revenue 
This feature is good
This feature is faster
PeopleWhat kind of person?manager, employee, developer, analyst, users
People will like this feature
Managers will like this feature
SentHow?FTPd, emailed, faxed
I sent the files
I emailed the files

Wednesday, January 5, 2011

They should not complain if...

Every project and team always has issues. I'm a big fan of making things better. No one wants to hear complaining (not to be confused with constructive criticism or a call for action). Here's a brain dump of when people should not complain:
  • They don't have a better alternative
  • They can't specify what the actual problem is (saying "something seems wrong, but I don't know exactly what" isn't complaining)
  • If their manager asks "what can I do", and they can't tell them
  • They caused the problem
  • They were warned, and did it anyway