The Pomodoro Technique - Scrum in the small

Over the past month I’ve been experimenting with the pomodoro technique of time management to great success.

The technique is surprisingly simple; yet I’ve found it contains a wealth of physical and emotional benefits. To give some context; I’m using it as a programmer as part of a agile scrum team. I typically program using TDD techniques. That being said, I don’t see why it wouldn’t be applicable in most “desk” based jobs.

A pomodoro is a unit of focused, uninterrupted time; measured by an egg timer. For me, 25 minutes works well.

At the beginning of my work day, I write a collection of tasks that I think I achieve in the day onto a fresh piece of paper as my todo list. I estimate how long I think each task will take in units of a pomodoros. Next to each task I put a number of boxes; one for each pomodoro unit. I make sure not to have more pomodoro units than I achieved yesterday; and I try to make sure that I’m estimating tasks based on how long similar tasks actually took me in the past.

Then I wind up my egg timer, place it visibly on my desk and begin the first task. The ritual of winding up the timer, placing it down and hearing it tick help me to drop into the zone of full concentration - and let my team know that they shouldn’t interrupt me.

Brrrriiinng. Pomodoro up, finish the current test and stop. Cross out one of the boxes on my todo list. Get up and leave my desk; stretch, drink some water, focus on something far away to relax the eyes, go an speak to anyone who came past during my pomodoro time & was waived away.

Then back to the desk, reassess which is now the most important task to get one with, and start the next Pomodoro.

At the end of the day I transcribe the results of my todo list back to a records sheet; update our project management software (VersionOne); and leave, satisfied that I achieved what I set out to do.

I’ve found that running my day like this greatly increases my job satisfaction & efficiency.

Firstly; I’m breaking my addition to hopium, and setting myself up to fail every day. I used to live in this lala land called - I have 8 hours of productive work time each day. The empirical reality shows that I usually do 5 - 8 pomodoro units / day - so much more like 3 - 4 hours. The rest gets gobbled up by meetings, emails, conversations. So its no wonder that I used to achieved half what I thought I would each day; and left work feeling disappointed.

Secondly, having a forced reset every 25 mins really helps me to stop falling down rabbit holes. I’ll often be trying to solve a problem with a specific technique that just isn’t working, and if I’m not careful I can spend a whole afternoon bashing my head against a wall. With the forced breaks, I’ll often find that I sit back down to the problem, and have a flash of inspiration for a much simpler way to solve it, or realise that I don’t even need to solve it in the first place!

Thirdly, being reminded to get away from my desk frequently really helps physically. I’ve experienced much less “mouse shoulder” and dry eyes.

The technique is also really helpful when pairing; keeping meetings from rambling; keeping focussed on one task (rather than having to check email or twitter every 10 seconds) and getting going on a large daunting task.

If you struggle with hopium like me; I’d really encourage you to give the Pomodori technique a try for 2 weeks, and let me know how you get on in the comments to this post.

Brrriiinng

Resources
www.pomodorotechnique.com

Functions with side effects are just rude!

Today I fell into a trap when using a function that had a side effect - it unexpectedly changed an input parameter; causing a later statement to fail. Debugging took an age!

For example, consider the following function:

1

      string StringReplace(string haystack, string needle)

If this function is side-effect free, we can use it without fear like this:

1
2
3
4
5
6

        string menagerie = "cat,dog,bee,llama";
        string catFreeMenagerie = StringReplace(menagerie, "cat");
        string beeFreeMengerie = StringReplace(menagerie, "eric");
 
        Assert.AreEqual(",dog,fish,llama", catFreeMenagerie);
        Assert.AreEqual("cat,dog,,llama", beeFreeMengerie);

However, if StringReplace() had the side effect of also changing the passed in haystack, then the second Assert would fail, because the first StringReplace has the unexpected side effect of changing one of its arguments.

Evans in the DDD book has quite a bit to say about this; arguing that having side effect free functions goes a long way towards making a supple design

Side effect free functions also make testing & refactoring easier (less state to worry about etc)

Remember, function that changes parameters entrusted is rude, and should not be trusted!

PS: Eric the half a bee lyrics

Selenium gotcha - selenium.GetHtmlSource() returns processed HTML

Whilst writing some Selenium based acceptance tests today; I bumped into a hair pulling gotcha.  Hopefully this post will prevent you from the same pain.

The test was to check whether some tracking tag javascript was being inserted into the page correctly or not.

I assumed that I could get the page source as it was being delivered to the browser by calling selenium.GetHtmlSource(); and then check that for the javascript string I was expected.

Unfortunately, GetHtmlSource is just a proxy for the browsers DOM.InnerHTML method; and that returns the Html after it has been preprocessed by the browser.

Turns out that preprocessing does a couple of funky things, including

• Changing line-endings (Firefox)
• Changing capitalization (IE6)
• Seemingly random removal / insertion of ” & ‘  (IE6)

So, when I was expecting a string like this:

1
2
3
4
5
6

<script language="javascript" type="text/javascript">
<!--
   var amPid = '206'';
   var amPPid = '4803';
   if (document.location.protocol=='https:')
...[snip]...

IE6 was presenting me with:

1
2
3
4
5
6

<SCRIPT language=javascript type=text/javascript>
<!--
   var amPid = '206'';
   var amPPid = '4803';
   if (document.location.protocol=='https:')
...[snip]...

A possible solution is to ignore case, whitespace and quotes when doing the comparison, with a helper method like this:

1
2
3
4
5
6
7
8
9
10
11
12
13

/// <summary>
        /// Use this to compare strings to those returned from selenium.GetHtmlSource for an Internet Explore instance
        /// (IE6 seems to change case and inclusion of quotes, especially for Javascript.?)
        /// </summary>
        /// <param name="expected"></param>
        /// <param name="actual"></param>
        private static void AssertStringContainsIgnoreCaseWhiteSpaceAndQuotes(string expected, string actual)
        {
            string expectedClean = Regex.Replace(expected, @"\s", "").ToLower().Replace("\"","").Replace("'","");
            string actualClean = Regex.Replace(actual, @"\s", "").ToLower().Replace("\"", "").Replace("'", "");
            StringAssert.Contains(expectedClean,actualClean,
                                  string.Format("Expected string \n\n{0} \n\nis not contained within \n\n{1}", expected, actual));
        }

It was the line endings that really floored me; because they were automatically normalized/corrected by my test runner when displaying the error. Aaargh!

The Correlation between Schedule Pressure & Low Quality

Research suggests that

• 40% of all software errors are caused by pressure on developers to complete quicker (Glass 2004)
• Under extreme schedule pressure, code defects increase by 400% (Jones 2004)
• Projects which aim to have the lowest number of defects also have the shortest schedules (Jones 2000)

This makes sense is you consider that good engineering practises are the first to leave the building under pressure to finish, and most teams will revert to quick & dirty hacks to get things implemented, without complete testing etc.

My personal opinion is that the only way to shorted development cycles is to reduce the feature set. Its pleasing for me to see that the research seems to back this up.

When deciding which features will be dropped; I think its worth revisiting the business requirements that are driving a particular set of features. In many cases a simpler “design” could suffice; for example a fancy calendar widget could be replaced with a simple textbox; a little used settings screen could be retired in favour of manually changing config files; or overly complex but little used workflows could be put on the back burner.

I maintain that a lot of “features” can be dropped, without actually impairing the business functionality of the system.

Just remember, what every you do DON’T consider dropping testing or QA in an effort to meet your deadline; unless you want to guarantee that you will continue to miss all future deadlines until the project gets cancelled!

Announcing the TDD TestHelpers opensource project

Whenever I start working on a project; I invariably find myself writing a collection of TDD test helper methods.  I quick survey of other TDDers reveals the same; and thus the birth of my latest opensource project, TestHelpers (http://code.google.com/p/testhelpers/).

The aim of the project is to centralise all those little test helper methods you end up creating into a useful assembly you can use to jumpstart your next project.  Things like:

• Comparers
  • Generic object comparers
  • DataSet comparers
• Test Data generators
  • Builder pattern
• Automocking containers

For example, I’ve just added an “AssertValues” functor; which helps you check whether the values of who object instances are the same. 

One area I keep using asserts like this is in integration tests; where I want to check that the objects I’m persisting to the database via my ORM actually end up in the database in a non-mangled form.  In this case, I new up entityA, persist it, reload it into entityB and then need to check that all the values in entityB are the same as those in entityA.

A standard Assert.AreEqual will fail, because entityA and entityB are different instances.  But, my helper method AssertValues.AreEqual will pass, because it checks the (serialized) string values of entityA and entityB.

Here is another, simpler example to illustrate the concept.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

    [TestFixture]
    public class StandardObjectsTests
    {
        public class StringContainer
        {
            public string String1 { get; set; }
            public string String2 { get; set; }
        }
 
        [Test]
        public void ObjectsWithSameValue_ShouldBeEqual()
        {
            var stringContainer1 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};
            var stringContainer2 = new StringContainer {String1 = "Test String1", String2 = "Test String 2"};
 
            Assert.AreNotEqual(stringContainer1, stringContainer2);
 
            AssertValues.AreEqual(stringContainer1, stringContainer2);
        }
   }

I’m sure you have a bunch of similar helper methods lying about your projects.

How about contributing them to the TestHelper project?

ALT.NET; London; 13 Sept 2008

Intro

Debate over what ALT.NET is; should it have a set of guiding principles like the Agile manifesto?

Continuous integration & deployment

There seemed to be 3 major areas where people encountered difficulties doing continuous integration & deployment.

1. Configuration files
2. DB schema migrations
3. Data migrations.

Using Acceptance Criteria & Text based stories to build a common domain language between business and developer

Image via Wikipedia

Besides precisely pinning functionality, writing text based stories has another - and some would argue more important - benefit, developing a shared domain language between the business & developers.

A large part of developing a new software application is defining and codifying a business solution. To do this, both sides of the equation must be molded to fit the constraints of the other - the business process needs to be expressed in a precise manner that can be automated in software, and software must be molded to fit the use cases of its users.

The mismatch between the way the business sees the solution, and the way the developers view the solution becomes painfully obvious about half way into the project, when you start to try to match what data fields are labeled on the UI, and what they are called in the database / object model.

I’ve worked on what should have been simple projects; where maintenance is a exercise in hair pulling as you try to figure out what data input results in the weird output in a report.

The root problem is a lack of a shared domain language. Projects naturally evolve domain languages; and unless guided, you can guarantee that the language in the customers requirements spec and that in the code base will diverge rapidly.

Sitting developers, testers and the customer together to produce written text user stories following Dan North’s classic BDD story structure goes a long way towards resolving this issue.

Talking through how functionality will work, and being forced to formalize it by writing things down helps the domain understanding and language to evolve naturally, influenced equally by the customers domain understanding, and the constraints the developer must work within.

Its vital that this is done before coding begins for the following reasons:

• All stakeholders have been indoctrinated in the same domain language
• Names for domain concepts are at hand when the developer needs them, resulting in better named domain objects.
• Both the developer and customer know exactly what functionality is expected; helping to keep both focused on solving the right problems.
• Facilitate ongoing conversations as the solution evolves. Evolving a shared language is difficult, and better done at the beginning of the project whilst everyone’s enthusiasm is high. With that hurdle out the way, ongoing conversations are easier, and the temptation just to guess, or devolve into an us vs them mentality is greatly reduced.

During release planning, the high level “As a [x] I want [Y] so that [Z]” is probably sufficient, with the “Given, When, Then” acceptance scenario’s being fleshed out at the beginning of each sprint.

Specifying your functional requirements as text stories leads to some exciting opportunities:

1. Your “unit” of work is immediately available, and understood by all. This makes prioritizing which stories to include, work on next, or drop much easier
2. Its possible to turn the stories into executable specifications.

The Ruby community has made the most progress in the latter opportunity, with their rSpec story runner.

Consider the possibilities of the following development practice:

• The team begin by specifying text stories & acceptance criteria.
• The testers turn this into an executable spec, with each step “pending”
• The developers then work from the executable spec, coding the functionality to make each step pass one by one
• When the customers receive a new version, the first thing they do is execute the stories, to see exactly which functionality has been implemented, and prove that all is still working as expected.

At any stage its possible to see how far the team is (how many steps pass?), speculative complexity is reduced because the developers are focused on developing only that which the test requires, and all the while a suite of regression tests are being build up!

The Complexity Retrospective

Many projects go awry due to excessive complexity; and its always worth evaluating whether your team is approaching things in the simplest way that can work; especially when the deadlines begin to loom.

I recently lead a retrospective with my team focusing on complexity across all the areas of our project, using the a handful of techniques from “Agile Retrospectives - making good teams great” (a must have for every agile team).

As suggested, we structured the hour long retrospective into 5 parts:

1. Setting the stage
2. Gather data
3. Generate Insights
4. Decide what to do
5. Close / Action plan

The purpose of “Setting the stage” is to get everyone engaged, and thinking about the same theme. To do this I reminded people of the actions we had set ourselves from the last retrospective, and then asked each person to complete the sentence “If we were a military commando, and our mission was last retrospective’s actions, we would be _______”

Awarded medals
Promoted
Ready for another mission
Court marshalled
Dead

I then told the team that in this retrospective we would be considering complexity, and whether we had too much, or just the right amount in each of the areas of our project.

To gather data, I drew a complexity radar, with each spoke a different area of complexity. I began by suggesting a couple of generic spoke names (Data model, Workflow), and then got the team to suggest the other areas. Using dot voting, everyone voted as to where they felt we ranked on each spoke, with closer to the centre being just right, and further away being overly complex. Joining the clustered dots produced the following radar map:

To generate insights we used the 5 whys excersize. I asked people to break into groups of 2, preferably cross discipline, and assigned each group 2 of the high ranking spokes. They were then tasked with asking each other “why is <spoke area> complex”, and “why is <answer>?” and so on, until 5 why’s had been asked. The answer to the 5th why was considered the root cause of the complexity, and recorded on a card. As the root causes cards came in, I grouped them, and when everyone was done, read the root cause groups out.

To decide what to do we constructed 2 more histograms, one considering the risk of the root cause, and the other difficulty to address the root cause. I then ask each person to vote which of the 2 root causes had had the highest impact & and which was the least difficult to address. This produced the following histograms.

In conclusion, we then combined the impact & difficulty histograms into the following map

My intention was that the final exercise would make it simple to choose the actions to take forward for the next sprint (basically chose the low hanging fruit - the easiest things to address which had the biggest risk reduction); but there wasn’t a clear winner shown on the graph.  Generating actions took a bit more discussion.

We found that this format was a fun and effective way to address the complexity problem.

Hopefully you’ll find running something similar with your own team helpful!

100% code coverage is only part of the QA story

Luke Francl of Tumblon has a nice summary with backing research showing how unit testing is only part of the QA story.

Its important to realise that developers by nature will only test the happy path; hence its likely that those diabolical edge cases will remain untested by a developer.

Another important factor is that most bugs come from missing features or requirements; and its impossible to unit test what isn’t there.

See more at http://railspikes.com/2008/7/11/testing-is-overrated; specifically Luke’s create Venn diagram showing how different types of testing (unit, user, code review etc) uncover different types of defects.

This isn’t to say that unit testing isn’t worthwhile; it just frees your testers up to concentrate on the unexpected, non-logical things that users are sure to try use your software for

What is the definition of Done?

 Scott Hanselman has a pretty interesting discussion with Scrum co-creator Ken Schwaber around the concept of when is a story Done.

http://www.hanselman.com/blog/HanselminutesPodcast119WhatIsDoneWithScrumCoCreatorKenSchwaber.aspx

Ken raising some interesting points, most notable that a well defined concept of Done, understood by all members of the project is a cornerstone of a good scrum process.  Without it, you can guarentee that you are building up technical debt; and your software won’t be in a releasable state once you have “Done” all the features, which kind of defeats the point of release planning!

So, what is your definition of done?

• All acceptance cases / test scenarios pass?
• Unit tests pass?
• Performance tests pass?
• Customers have used and approved the feature?

Next Page »

• Categories

  • Agile
    • Retrospective
  • Architecture
  • HOWTO
  • Humour
  • Platforms
    • .NET
    • ASP.NET MVC
    • MSSQL
    • Ubuntu
    • Wordpress
  • Software Craftmanship
    • Code smells
    • Refactoring
    • TDD
    • Technical Debt
  • Uncategorized

• Archives

  • June 2009
  • May 2009
  • March 2009
  • February 2009
  • December 2008
  • November 2008
  • October 2008
  • September 2008
  • July 2008
  • June 2008
  • May 2008
  • November 2007
  • October 2007

• Links

  • Business Coaching
  • Software Craftmanship 2009

• Meta

  • Register
  • Log in
  • WordPress
  • XHTML

• Tags

  acceptance test Agile apache2 ASP.NET MVC autofs automapper backup backup-manager bdd c# estimating msi pam plesk rsync.net scrum selenium sshfs ssl story points story runner TDD Ubuntu utils-anti-pattern ViewData ViewUserControl wordpressmu wpmu

  WP Cumulus Flash tag cloud by Roy Tanck requires Flash Player 9 or better.

• Recommended reads

  

  

  

  

  

• Latest del.icio.us links

  • WP Execution Roadmap 2009/07/03
    Shows the order of execution for any page in WP
    
•