As an app and browser testing expert with over 10 years of experience across 3,500+ real devices, I‘ve seen firsthand the benefits of shift left testing. This approach improves code quality, speeds up delivery, and enhances customer satisfaction – but it requires changes in processes and culture.
In this comprehensive guide, I‘ll explain everything your team needs to successfully shift left. I‘ll cover:
- What is shift left testing – A quick overview
- Shift left principles – Core concepts
- Implementing shift left – What changes
- Benefits – Why it matters
- Challenges – Common pitfalls
- Best practices – Pro tips
- Automating shift left – Testing earlier
- Driving culture change – Getting buy-in
I‘ll also use plenty of examples, statistics, and visuals to illustrate key points. My goal is to help you deliver better software, faster. Let‘s get started!
What is Shift Left Testing?
Shift left testing shifts quality control and testing left in the software development life cycle (SDLC). That means beginning testing earlier, as code is being written, versus later before release.
Let‘s use an analogy. Think of software development like building a house. Traditional testing peeks at the nearly completed house right before the open house. Shift left testing checks the foundation as it‘s poured and monitors construction from day one.
By testing earlier, teams catch bugs and defects when they‘re 10x cheaper to fix – averaging $100 vs $1,000 if found in production as the below graph illustrates:
Source: Capgemini
Studies by Deloitte, IBM, and more confirm this benefit. Shift left testing reduces costs, speeds releases, and improves quality – enabling you to delight customers with better software, faster.
Shift Left Principles
Several core principles characterize a shift left approach. Understanding these helps teams implement the associated cultural and process changes.
Test Early, Test Often
Testing should begin as early in the software development life cycle as possible – at the requirements stage or when architects and developers begin designing components. The key insight is over 50% of defects originate in the design phase, before coding even begins!
By testing early, issues get caught sooner – avoiding bigger headaches down the road. "An ounce of prevention is worth a pound of cure". For code changes, aim to test in minutes versus waiting days or weeks.
Everyone Owns Quality
With shift left, quality is everyone‘s responsibility – not just dedicated QA testers. Developers test their own code functionality. Architects validate designs. Ops tests deployments. Product looks for gaps. By owning code collectively, teams rapidly improve quality.
Prevent Defect Flow Downstream
Like a river, defects that escape upstream end up flowing downstream, gaining volume and momentum. What might have been a small one line fix early turns into a raging torrent requiring major rework by release.
Shift left stems this tide through gated checklists each step of the way – code reviews unit testing, regression testing, performance testing, staging testing, canary testing, and more. Do this well and what flows downstream is clean, pristine water.
Rapid Feedback Cycles
The final pillar of shift left is rapid feedback at each test phase. Test automation kicks off continuous flows of feedback into planning and development – fueling continuous improvement and quality. Through this cycle, teams get smarter and software gets better.
Armed with these core principles, let‘s look at how to put shift left into action on real projects.
Implementing Shift Left
There are two primary strategies for implementing shift left:
1. Involve Ops Early
Include DevOps engineers during requirements, design reviews, and architecture planning. This allows deployments, infrastructure, monitoring to be built correctly the first time – avoiding costly rework fixing inconsistencies later between environments. Netflix is a pioneer of this "you build it, you run it" model.
2. Simulate Production Environments Early
Use cloud sandboxes, containerization, and service virtualization to mimic production environments earlier in the dev lifecycle – for integration testing, load testing etc. This shift left testing hardens code against real world conditions versus just best case scenarios.
In both cases, collaboration drives alignment and quality:
- Developers understand operational constraints upfront
- Operations understands and enables testing needs
- Automated testing and monitoring woven throughout
Now let‘s examine why this shift left approach delivers such strong business benefits.
Benefits of Shift Left Testing
Studies by leading research firms validate the following benefits of shift left testing:
70% reduction in defect costs
IBM found defects found by automated testing vs later manual testing or users to be 10x less expensive to fix. This matches the earlier chart showing identified defects earlier are exponentially cheaper.
80% improvement in release velocity
A McKinsey study of rapid software techniques found dev teams able to release changes in hours/days versus weeks/months significantly accelerate value delivery and ability to meet business needs.
60% productivity boost over waterfall methods
Capgemini consulting found agile teams leveraging shift left principles were substantially more productive than sequential waterfall teams.
75% faster time-to-market
Shifting testing left compresses lead time between business idea and software release – fueling competitive advantage.
Added together, shift left testing powered by test automation allows enterprises to leapfrog rivals through better quality and faster delivery.
Challenges With Shift Left
Given the benefits, why hasn‘t everyone adopted shift left testing? Because it represents an enormous cultural and process change. Common challenges include:
Inertia to change: Teams accustom to certain ways are resistant to evolve – like asking waterfall teams to go agile.
Lack of test engineering skills: Developers unfamiliar with writing test automation code or using new frameworks.
Coordination overhead: Shifting left requires more collaboration, communication, and synchronization across roles.
Spotty tooling: Homegrown scripts and test environments slow down test creation and execution.
Unclear metrics: Measuring coverage, escapes and other key testing metrics not in place causes visibility issues.
Testing bottlenecks: With more testing earlier, lack of automation scales create congestion.
The key to overcoming these issues is executive leadership, training, and picking initial pilot projects wisely – recognizing larger cultural transitions occur gradually.
Now that we‘ve covered the fundamentals, let‘s drill into the nitty gritty around 20 specific best practices your teams can implement starting today. This is where the rubber meets the road.
Best Practices For Shift Left
Here are real world proven practices to drive shift left success based on my decade plus experience:
Planning
Create a Shift Left Testing Strategy
Define what testing occurs when, which roles responsible, automation needs, and success metrics. Enforce this through gated checklists for code commits and sprint reviews.
Specify Test Environments Upfront
Detail the test data, virtual services, tooling, and cloud resources needed to simulate production scenarios – and provide them! Nothing slows shift left adoption more than test bottlenecks.
Integrate Business Use Cases
Work with product and customer teams to build out key user journeys and acceptance criteria early – which feed testing scenarios. Align incentives through bonuses for identifying defects or gaps.
Building
Design Components for Testability
Expose APIs, log activity, add test endpoints in components to simplify automation. Don‘t wait until something is 100% built – test foundations first. I enforce this through a definition of "done" checklists.
Develop Incrementally
Tight feature chunks are easier to test versus big bang releases. Think train cars versus locomotives. Automate confirmation of each chunk before advancing.
Review Code Early and Often
Code reviews catch logical issues unit tests can miss but require time investment. Budget this into sprints. Rotate testers and developers reviewing to spread knowledge.
Testing
Start Testing on Day One
The second a requirement is captured or component designed begin building automated validation checks through API mocking, unit tests, etc.
First Test The Riskiest Areas
Have testers and developers buddy up to identity parts most prone to breakage – complex logic, interconnected services, sensitive systems etc. Then focus test scenarios there.
Prevent Scope Creep
Limit components under concurrent testing to avoid clogged feedback pipelines. Feature flags help safely test high risk changes in production while minimizing scope.
Favor Exploratory Testing
While test automation is key, don‘t overlook manual poking, prodding and tinkering to find edge cases. Set time for this every few days.
Monitoring
Inspect Code Coverage
Code coverage identifies areas with gaps in test automation. Aim for 70%+ unit test coverage and near 50% overall coverage.Anything below signals risk of undetected bugs.
Track Escaped Defects
Monitor defects discovered post deployment vs earlier through x-ray sessions and calculators. Target no more than 10% escaped defects long term. Analyze how they escaped and add automation checks.
Monitor Technical Debt
Fixing defects creates more maintainable code over time IF teams are diligent addressing issues. Leverage code quality tools assessing technical debt and block code rot.
Study Customer Behavior
App performance tools identifying confusing UX flows, unused features, crashes etc coupled with direct customer interviews provide pure gold to remove obstacles and enrich experiences. Don‘t waste this free feedback!
Automating
Test automation is the engine enabling shift left testing by allowing earlier and more frequent execution. Use guidelines like:
- Automated validation for every new feature
- Developers author test cases as they code
- 70% unit test coverage thresholds
- Leverage API testing and service virtualization
- Every build triggers automated regression testing
- Tests execute on code check in enforcing quality gates
Prioritize Automation Efforts
Like everything, there are automation opportunities with bigger versus smaller ROI. Have testers walkthrough user journeys identifying points with:
- High likelihood of breakage
- Wide downstream impact
- Frequent execution
- Manual testing pain
Automating these high value areas first gives the biggest bang for buck. You get 80% of the value from 20% of test cases.
Validate Against Production Early
Simulate real user scenarios early on actual devices and environments through crowd testing services versus just happy path testing onlocalhost. This hardens code for the real world and avoided countless issues for our teams over the years.
Avoid Automation Pitfalls
Certain missteps plague test automation efforts. Watch for:
- Brittle tests requiring constant maintenance
- Low level scripts testing implementation details not behavior
- Tests can pass yet customer scenarios still fail
- Hard coding environment details tightly couples tests
Build automation correctly from the start through practices like behavior driven development (BDD).
Invest in Automation Engineers
Dedicated automation engineers create the scaffolds making testing easier for the broader team. They build frameworks, create shared services, generate data etc. Prioritize hiring automation talent.
Driving Cultural Change
Perhaps the biggest barrier I‘ve seen trying to shift left is culture. Test organizations are especially resistant having spent decades in specific roles. Here are proven ways leaders can drive change:
Communicate a Vision
Share measurable goals for what shift left testing accomplishes, set realistic timelines, and clearly tie to financial impact. Repeat often.
Incentivize Behaviors
What gets measured gets improved. Recognize contributions to quality through peer bonuses, testing leaderboards, etc related to prevention of escapes, automation coverage growth, and reduction of upstream defects.
Remove Constraints
If your approval processes or procurement rules makes executing shift left testing painful, fix them now. Empower teams to choose tools meeting their needs.
Lead by Example
As leaders, roll up your sleeves to both demonstrate and educate through side-by-side paired programming and testing sessions with your teams. No amount of words match walking the walk.
Celebrate Shift Left Heroes
Publicly highlight teams and individuals furthering shift left testing through newsletters, meetings, and internal social channels. Make it clear this capability is valued.
Keep Improving
Get feedback through regular touchpoints on what problems teams face adopting shift left, then turn findings into improved tooling, training and processes. Quickly resolve constraints.
Gradually behavioral incentives, peer pressure, and new processes will make shift left second nature. Teams will see for themselves the benefits through better software and faster delivery.
So in summary, shift left testing delivers tremendous advantages: faster delivery, lower costs, and happier customers. By following the expert best practices outlined, your software teams can release higher quality code through test automation and cultural change. Now go unleash the productive power of shift left testing in your organization!
