Day 4 – Summary of the Agile Course so far (Part 1)

Below are my notes from the Agile course so far – covering introduction to Agile projects , why it makes business sense, the use of FIT and other acceptance testing tools what Agile means for customers , managers and teams.

These notes are a good complement to the Agile presentation I gave.

Introduction to Agile

• Requirements
  Change on project – it’s going to happen , clients (paying for the code) have the right to change their mind , accept it and get on with it.

• Agile Family Includes

  • XP (Extreme Programming)

  • Scrum

  • Adaptive Software
    Development

  • Lean Software
    development

  • Feature Driven
    Development

  • Crystal

  • DSDM

• Values
  wrap Principles wrap Practices

• Values
  (from the Agile manifesto)

  • Individuals and interactions over processes and tools.

  • Working software over comprehensive documentation.

  • Customer collaboration over contract negotiation.

  • Responding to change over following a plan.
    

• Principles
  (Customer Focused)

• Deliver early, deliver often.

• Deliver valuable software.

• Welcome change.

• One
  Big team (business people and developers)

• Principles (for Management)

  • motivated individuals give better results

  • face 2 face is the best way to communicate (although accept need to
    communicate across location and across time as good 2^nd
    best).

  • Remember : working software that meets business needs is the primary measure
    of progress

  • Promote sustainable development (or you’re just going into Technical Debt)

• Principles(for Teams)

  • use technical excellence and good design to promote agility but

  • simplicity is essential

  • the best architectures, requirements, and designs emerge from
    self-organizing teams (rather than imposed from above)

  • do continual improvements to the process

• Practices

  • Continual Improvement

  • Technical Excellence

  • ProjectManagement

  • Business Practices

  • Community and Collaboration

• Why Agile

  • Waterfall projects : we’re most likely to find bugs in testing phase at the
    end , when (a) we’re most likely to be under time pressure and (b)
    when they’re most expensive to fix.

  • Waterfall projects: Hard to know how far through we are , as each step is
    different from the last (design has gone well , but will coding do
    better or worse?)

  • Agile:Testing is continuous, so likely to get early feedback and
    resolution of bugs. Testing = Unit Tests and Acceptance Tests.

  • Agile: Progress is steady and measurable , as we carry out all
    tasks as part of a regular cycle.

  • Productity = doing less but producing more value. e.g. Customer can prioritize
    highest value tasks and we deliver these first.

  • Standish group stats showing small projects are more successful.

  • Deploy early and often gets usable software into the hands of users sooner
    where it can start to payback it'[s investment earlier.

  • Success factors for Agile projects:

• Enthusiastic development team/ Committed customer / Knowledgeable on-site QA
  resource / Didn’t cherry pick practices / Open workspace / Regular
  retrospectives.

• Still hard work to do:

  • Good people give good software

  • Can be faked , so people really need to buy in

  • Practices are learnable / a lot are common sense

  • Recognize reality

Informative
Workspace

• Person walking into ‘normal’ coding office has no idea of what is going on, nor what status it is at. Most of the stuff is in people’s heads.

• Informative workspace seeks to communicate this information (via simple methods)in the office e.g. Notice boards, coder of the week hat , printed graphs of velocity , iterations etc.

• Kent
  Beck : "An interested observer should be able to walk into the team space and get a general idea of how the project is going in 15 seconds. "

• Similarto Kanban idea – while going for Just in Time / continual improvement , visual representations are displayed to demonstrate
  progress.

• Information Radiators : anything that gives out info (example given of monitor running , showing latest build progress).- jokey examples of Lava
  Lamps / notes in toilet

• Toyota (Toyota production system – recognise their edge is in how they build their cars, and not just the cars that they build).

  • Human face to automation.

  • Board giving current
    production status

  • Audible Cues

  • Ability for anybody to stop the line.

Testing and Design by Contract

• Started by Bertrand Meyer in the Eifel Language

• Frameworks available to add these (fully) to the Java Language – over and above the functionality available in Java 1.4 (the assert keyword)

• Already have a contract that is enforced by the compiler in Java (e.g. Method signatures , return types)

• Adds to this , to be a finer grained level .e.g method should return not only an Integer , but an Integer of value 0 to 100

• Like every contract both sides (Caller and Callee) have responsibilities

• Pre Conditions : Condition that must be true when the method is called.

• PostConditions: Condition that the method guarantees when it returns

• Class Invariants state what will be true at a class level (once all pre-conditions at method level / constructor level satisified)

• Both pre and post provide additional specifiication (.ie. It is clearer to people using the code what is required / what it does). As such
  provides clearer design and additional documentation.

• Can make code more succient by replacing ‘boilerplate’ code with standard check (e.g. Precondition param must not be null).

• Java
  Example :

  • Pre
    Condition /** @require !empty() */ – as
    javadoc on method (multiple checks allowed) –

  • Post
    Condition : /** @ensure !full()*/

  • Class Level invarient: /** @invariant 0 <= count()*/

• Exceptions

  • Pre Condition violation should give RuntimeException – provide method to test before call (e.g. IsEmpty() before doing remove)

  • Post conditions: supplier should be every effort to fulfill these : so if it can’t , it is normally due to an Exception (callee should be prepared for this failure)

• Junit

  • Codein Junit verifies the contact of the class (and provides documented example of code use)

  • assert methods = post condition testing

  • test invarient by checks at class and not just method level (e.g. Check overall status of class, not just return value of method under
    test)

  • Pre conditions by be tested by violating these in setup (code before call to method/ class under test) and ensuring exception is thrown.

• Think about Test as a contract.

Acceptance Testing

• Acceptance Tests – defined (or agreed by customer) , states thatfunctionality is complete

• Differ from unit tests in that they are system wide rather than at class/unit level.

  • Sometimes people used high level / coarse level Junit tests.

• Unlike unit tests don’t need to be a 100% all the time (but once passed , should alway pass)

• Automation is nice (for developer and customer)

  • Own note: Not everything in acceptance testing is automatable. e.g. UI testing.In this case automating the acceptance testing of the calculations (the 80%) means that the UI testing is a lot easier.

• Sample Frameworks for Automated acceptance testing

  • FIT – see notes below

  • Exactor – see notes below

  • Fitnesse – FIT but wiki based (easier to do multiple tests , easier to communicate these to a team.

  • WinFIT runner

• Inputto all these tools is close to a spec (close in that typicaluser , after one walkthrough should be able to understand what the documents mean).

• Tests can be written before application is build (again, the notion of the tests forming a spec). A lot of the commerical tools ,
  especialy those that record against a ‘live’application, do not allow this.

Automated Acceptance Testing with FIT

• FIT
  – http://fit.c2.com– Framework for Integration Testing

• Allows Customer s to review (if not write) the acceptance tests.

• Previously would have done these tests manually , or via large Junit tests (i.e. Use Junit not as Unit testing , but a way of describing the entire app from the user point of view).

• Data (unlike in Exactor) is specified as a HTML table. All non-tables are ignored (so safe to created tests documents using MS Word).

• Fixture (connects this HTML Data) to run test against ‘production’ code.Fixtures are written by programmers (as part of proving code meets
  the spec). Three types of fixtures.

  • Column

    • One class for each table

    • Fit works through on a line by line basis – good for repeating the same action over and over again.

    • 1^st Line of Table : Class Name to be tested

    • 2^nd Line of Table : class variable or methodName() to be set / called

    • 3^rd –
      Xth lines of table: values to set or expected values to be returned

    • Good for testing Domain (Business) Logic parts of an application

  • Action

    • mulitiple class for
      each table

    • start – the class to be tested

    • enter – value to be passed into method (no return value)

    • press – call method (no input or output)

    • check – check value on method (no input)

    • Good for stimulating interaction with the user interface (or more accurately either the controller that sits just behind the user interface).

  • Row

    • Like Column , but interprets all at once (rather than one at a time)

    • extend RowFixture ,
      provide query[] and getTargetClass() methods – allows Fit to see what data structure

    • good for testing coding in the service / persistence / db layer of code.

Automated
Acceptance Testing with Exactor

• Exactor (http://exactor.sourceforge.net)
  

• Allows Customer s to review (if not write) the acceptance tests.

• Previously would have done these tests manually , or via large Junit tests (i.e. Use Junit not as Unit testing , but a way of describing the entire app from the userpoint of view).

• Comprises (like fit) of

  • Script – a text file thatyou could show the customer.

  • Commands : what the script calls , extends Exactor classes. These commands then call the code beingtested.

  • Command extends Junit assert –
    so usual capabilities available.

  • Command provides access to test wide map to allow storing / exchange of values.

  • Allows composites to reuse scripts.

  • Scripts allow placeholder parameters