Just a few sections to end this blog post serie.

Just store it somewhere safe

Now I had a few productive days. I could easily do Test Driven Development with the help of the junior DevOps engineer. But I left out one important step in the development: the use of the version control system.

Looking at the numbers I think that Windows 10 is better than Windows 8.

One of the advantages of version numbers is that I know which platform the user used. And which version I have to use to pinpoint a problem in production. Versions are great for code.

Writing code is like making a story for a movie. If I made an error, then I reverted the change using Undo. Most of the time several people are involved for making the same movie story. There are a lot of people willing to pay 8 $ for a good movie. Coming soon to this cinema

Let’s take an imaginary superhero movie. Pete knows a lot of action scenes. After a while he describes a scene to the other crew members:
“And then she flies in the air.”
“Sorry Pete, but Lightning Buzzword Angel cannot fly.”

“But she is called Angel and angels can fly.”
“You’ve got a point, Pete. But not every woman called Angel can fly.”
“So I have to rewrite the whole scene.””
“Sorry dude.”
“It took me weeks to figure out this scene.”
“It is great, but we have to stick to the character.”

“So you just have to start from version 0.3 of the Supermarket Fight Scene.”
“But I also changed the First Car Ride Scene and the Milkshake Scene because of the bruises made by Oval Owl.”
“Wait, you say bruises.”
“Yep.”
“But then I have to rewrite my scene.” Amy remarks.
“And I the Milkshake Scene.”, another writer joins in.

Making a story for a movie is like writing code. If a programmer or DevOps engineer changes a method or function, then this can have severe consequences for the code. The trick to detect faulty code as early as possible. There’s absolutely nothing wrong with that.

Using Test Driven Development or TDD in a proper way a DevOps engineer knows that the added code is right.
Using a version control system she or he can merge the added code with the code in the repository. The result of all unit tests for this file is an early indicator for the quality.
Then the integration tests would be added, merged, and executed.

Now comes the most interesting part. If a release was made in this particular company, all unit tests and integration tests for the whole code were executed. All the tests from previous TDD or Red Green Refactor cycles were reused again. Of course some tests would fail, but the DevOps engineer would set things right. This could be the code or the test or both. And yes, this could lead to refactoring or restructuring code with an eye for maintenance.

After a few days of TDD a new file could be checked and processed in case of positive checks.

Just me and the code

During the coding the DevOps engineer mentioned the Boy Scout’s Rule. Now we were not exactly hiking. Not especially with a flatscreen attached to a laptop. The rule basically states that I should leave the place cleaner than when I came. If I found some rubbish, then I would have to put it into a bin.

In case of software it is all about refactoring and adding missing tests. And that was the case. Missing tests could be considered as technical debt. Yes, tests are technical.

There were still some unit tests missing for other input files. And then old patterns emerged again. I started to write Gherkin files and the DevOps engineer was making them operational. After a few days he started to work on a high prio task and I was still fabricating unplugged unit tests. Then I had to turn my attention to a high prio work item. I put all the unit tests in the version control system and almost forgot them.

Just plug and test

“This takes a few weeks.”
This was the initial thought from my scrum master after the request to plug in the remaining unit tests.

Okay, rhyme after me:
I was high
on supply.

There was one simple way to change his view. I put in the whole file with unit tests and the tests were not executable. So I cut a few times until I had only one simple test left over. It was still not usable.

I needed a default input file. My scrum master agreed:
“It takes some time, but it is worthwhile.”
I slowly assembled a file over a few thousands bytes character by character using an ASCII editor. This took a big chunk of one business day. Then I could code to run my first unit test. And I got a successful test, Green.

I slowly added the other unit tests. I was quite pleased with myself until I had a failing test. Red. This must have been a programming error. I checked the knowledge management system. I was right. Next result of the same test was again Red. Of course, because I did not change it a bit. Pun intended.

I slowed down to a crawl. According to the knowledge management I was right. This time I checked the value character by character. Hmm, time for a chat with the Product Owner.

He listened to my story and told me, that my test was right. So I updated the Knowledge Management System. At last a succeeding test. Green.

This happened a few more times.

That’s it?

This serie described my experiences with Test Driven Development or TDD. For me it was often difficult to stick to Red Green Refactor.  I made a lot of errors on my way. These things can happen. Even for experienced testers there are a lot of chances of being sidetracked.

Some readers might have noticed that Gherkin is used for unit tests. And this might be strange or unsettling. For me it was normal. In this company the DevOps engineers worked that way. It worked, so as a tester I had to put in more effort to find bugs. Sure no problem.

Me programming

My first action was to write a test to check a business rule for a valid observation date. While I was typing, the Integrated Development Environment aka IDE suggested several options like a search engine like Google. But observation date was not known. So this sentence was highlighted in red. Syntax highlighting is also handy in programming. I don’t mind that at all.

With the help of the DevOps engineer I wrote code in Java, so the IDE could use observation date in Gherkin. The code could be executed, but the test failed. Hey that was bad.

“Now I write the code.” was my next thought.
Of course there was no code, so the test should fail. Definitely Red.
This would be fun.

I had to program in Java and I remembered that the junior DevOps engineer had some useful shortcuts. I looked in the IDE and found the option in a sub menu to add a method. I gave it a name and – yes – I got an empty method in the right class. Now I had to fill in the blanks.

Me writing Gherkin

Months earlier I had written several Gherkin unit tests in the knowledge management system. There were two things wrong with this approach. The tests were not used, so I was high on supply. In plain English I had made something which was not used. On a scale of time it was a waste of time.

The other thing was that it had a web interface. The syntax highlighting did not work. I could make things bold and indent texts, but that slowed me down too much.
The result, the code, was not easily readable.

The dates were in the following format DDMMYYYY. This is programmer s’ language for Day in 2 numbers, followed by Month in 2 numbers, and finished with Year in 4 numbers.
So April 1st 2001 would be written down like 01042001. 01 is the first day of month number 04, which is April. 2001 is of course the year. It is easy to pick good dates like

• 01042001 (first day of the month),
• 31032013 (last day of the month), and
• 29022000 (leap day).

I picked some wrong dates on more rational grounds:

• 07142011 (for the Americans July 14th 2011),
• 20132007 (20th day of the 13th month), and
• 1jan1998 (January 1st 1998 in a hydrated date format.).

After writing date tests for one date field I noticed a pattern. I would check on all these dates again for other dates like expiration date. I thought I was smart. I just copied all the observation date tests and replaced ‘observation date’ by ‘expiration date’. I even copied the tests to a special text file, so I could save time. But I was wrong!
Please read on.

Me at the keyboard again

So I was programming unit tests and on my side was a junior DevOps engineer assisting me. I could finally write a test in Gherkin. In a separate window I opened the knowledge management system. I picked the first right date 01042001.
“Why do you pick this date?”, my personal DevOps engineer informed.
“I want to be sure that the right date is accepted.”
A nod followed by:
“We use Joda-time for that.”

I heard: “Yoda time”
It was not possible for me to link a lightsaber wielding big pointed eared green creature with programming.
“Joda-Time checks on valid dates, so you do not have to test them.”
Java 7 was not safe enough for dates and some programmers made Joda-Time. That saved me a lot of time.

So I only had to test on the wrong dates. Easy. I added tests, which succeeded. Green.

There was a `but` coming up.
“You can skip that date.”, while the DevOps engineer referred to ‘1jan1998’.
“Characters are not allowed in the date. ”

The next morning the DevOps engineer showed me a neat table:

Given the file has observation date <date>
When the file is read
Then the file will not be processed

Examples:
| date     |
| 07142011 |
| 20132007 |

He had improved the test code considerably. Refactor. I forgot to use DRY, Don’t Repeat Yourself.

My scrum master said that it was important to know how to program. This way I could structure my tests in a good way.
But the worst was still to come.

To be continued.

“At the moment I am writing a serie of blog posts about Test Driven Development.”
I looked to the recruiter. “You can understand it.”
I moved my view to the manager: “You can also understand it.”

Sticky note: let’s stick to the DevOps engineer.

Vegetable As a Service

The DevOps engineer wrote the unit test in Gherkin. The main advantage is that this language is easy to read. Have a try.
Given the version number is 15
When the file is read
Then the file will be processed

It is also easy to write. This example is in English, but it is also possible to use plain Dutch.
Gegeven een versienummer is 15
Als de file wordt gelezen
Dan wordt de file verwerkt

This is easy for people in Dutch companies. Nothing is lost in translation. It is easy to digest. No mindreading skills are needed.
The tool Cucumber provides a way to translate these sentences to a programming language like Java. A programmer has to code, how the sentences are translated.

When this little story is used by the computer, Java is used to execute this test. Yes, it is time for another cup of coffee. Which is the symbol of this language.

There are of course some people, who want to add some details to it. And yes, this is necessary.
Feature:
As an administrator I only want to process the right file list_20180525.txt, so that marketing managers can still process the data and generate reliable reports.

Background: file A

Scenario: 15 right version number
Given file A has version number 15
When file A is read
Then the file will be processed

Scenario: 16 wrong version number
Given file A has version number 16
When file A is read
Then the file will not be processed

All the text is put in 1 file, so all tests are nicely organised. A very important detail is, that file A is a complete valid file. This takes some time and some byte shuffling, but it is worthwhile.
So after 2 cycles of Red Green Refactor two scenarios were added in a feature file. These scenarios could be executed individually or in a group.

Then the cycle continued. The latest test was used frequently to assure, that the code was modified in the right way. The previous tests were used to assure, that the quality was the same. This led to a massive set of tests.

What’s next?

The DevOps engineer looked for the next feature to program. I saw an impressive table of valid values and validation rules.
“Do we have to test all this?”
“No”, he answered.
I could not believe my ears. There were so many places where things could go wrong.
“We will only test things, which can cause problems in our software. [The postman] will check the data.”

I visualised the data flow in my mind. There was a sender, which gave a file to the postman. This program would check every byte of the file. After a successful check the postman would deliver the
file to the receiver or the program under development. In the past I heard, that sometimes some things were not properly checked by the postman. With the speed of computers today extra checks can be done very fast.

The DevOps engineer continued:
“If data can cause problems in the software, these are checked.”
Version number is a good one. And of course begin date and end date of a period are also important.

Another cycle to start

This looked so easy.
It was like the junior DevOps engineer had some mindreading skills.
“Now you try.”
I was silent for a moment.
I repositioned myself after the keyboard and the mouse.
Pair programming. The real stuff.

Okay, let me start.

Read mindfultester[dot]com
My answer in a job interview

To be continued