Code Integration Strategies

Integrating the Code during the Development

Alexander VakrilovTelerik Corporationwww.telerik.

com

Why we need integration?

Faster bug detection Less bugs Improved code quality Shorter release cycle Accurate status quo Better customer relations Improved morale

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Integration frequency

Phased or Incremental

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Phased integration Steps

Develop unit by unit Combine all units into the big

system Test and debug the whole system Hope everything will work

together

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Phased integration problems

“Big bang” integration Phased integration comes late to the project

Problems might come from every unit or from combination of some units

Some typical problems: Shared global state Weak encapsulation Poorly documented interfaces

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Incremental integration Integrate one unit at a time Steps

Start with a small functional part of the system. It will a skeleton for the project

Develop a single unit (code, test, debug…)

Integrate the unit into the skeleton and verify its behavior

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Incremental integration benefits

Errors surface immediately You always have something working Better customer relations Improved team confidence

Improved progress monitoring More robust unit testing Shorter development schedule

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Incremental Integration StrategiesIntegrate “your way”

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Top-down integration Write classes on the top of the hierarchy

first Main Module / Main Window first

Benefits: Control flow logic is tested early on Conceptual problems are exposed

quickly Postpone design of low-level details

Disadvantages Tricky integration parts are

exposed last There maybe no top component Requires large number of stubs

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Bottom-up integration Write classes on the bottom of the hierarchy first

Benefits: Troublesome low level integration

problems are found quickly Disadvantages

The big picture is blurry High level integration starts

later on The whole system before must be

designed before you start integration.

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Sandwich integration Steps

Write classes on the top of the hierarchy first

Write low level integration pieces after that

Write middle level components last Benefits:

Combines benefits of both top-down and bottom-up approaches 11

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Risk-oriented integration

Steps Identify problematic (risky) areas Start from most difficult and

uncertain parts first Benefits:

Problematic areas are exposed early on

Disadvantages Initial progress is slow

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Feature oriented integration

Steps Develop one feature at a time Integrate this feature back to the

skeleton when its done Benefits:

Removes scaffolding Progress monitoring Works well with

Object-Orientation13

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Your own integration All mention approaches have benefits and draw back

Use what works for you and your team for this specific project

Don’t be afraid to mix and match them

Golden mean is the key to success

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Daily (CI) Build and

Smoke TestKeep your project healthy

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What is a CI Build? Code is checked-in to the source repository

A build is triggered on a separate build machine

Source is compiled and tests are executed

The build either succeeded or failed

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CI Benefits Build is healthy all the time Easy defect diagnostics and bug hunting

Constant availability of a "current" build for testing, demo, or release purposes

Early warning ofbroken/incompatible code

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CI Best Practices Build often Fixing a broken build is top priority Create a penalty for breaking the build

Tests are part of the build Automate the CI Build as much as possible

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CI Best Practices (2) Establish a build group Do CI at any cost, even under pressure

Setup a nightly build

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Code Integration Strategies

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