As an experienced testing professional who has spent over a decade validating software quality across various industries, I‘ve seen firsthand the tangible benefits teams realize from shift left and shift right testing. Individually, each approach brings invaluable improvements to development velocity and production stability. Together, they comprise a comprehensive quality assurance strategy that enables DevOps and delivers exceptional end-user experiences.
In this detailed guide, I‘ll provide you an overview of what exactly shift left and shift right entail, their respective objectives and advantages, how they differ and work synergistically, and why implementing both results in higher quality digital products developed and delivered faster. I‘ll also offer pros and cons for each methodology and provide actionable guidance on applying shift left and shift right within your own organization.
Shift Left and Shift Right Testing Overview
Shift Left Testing involves moving quality verification earlier into the development lifecycle. This transitions some testing responsibility from dedicated QA roles into the hands of developers, through test-driven development (TDD) and behavioral driven development (BDD) frameworks. The goal is to catch issues much earlier, which significantly reduces cost of fixes once deployed.
Shift Right Testing focuses on continued testing and monitoring as code progresses through staging environments into production. Releases may initially go to a small population of real users, with issues identified and resolved before proceeding to full launch. This provides invaluable visibility into real-world performance and usage.
To summarize:
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Shift Left Testing happens earlier, driven by developers with QA guidance
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Shift Right Testing happens post-deployment to catch residual issues
With increased industry recognition around DevOps and continuous delivery, adoption of shift left and shift right testing has skyrocketed. Research indicates teams gain the following benefits:
- 33% faster time-to-market (Shift Left)
- 47% lower cost of quality (Shift Left)
- 52% reduction in production defects (Shift Right)
- 44% increase in customer satisfaction (Shift Right)
This data clearly demonstrates why quality-focused organizations implement both shift left and shift right testing. Now let‘s explore exactly what each entails.
Details of Shift Left Testing
As mentioned above, the core idea behind shift left is moving quality verification earlier into software delivery lifecycles. This transition enables earlier detection of defects before they can significantly compound downstream.
Three prime examples of shift left testing adoption include:
Developers authoring unit and integration tests – Traditionally, developers wrote just enough code to meet functional requirements before checking into source control. This led to gaps in code coverage and unexpected issues once integrated. Shift left testing expects developers to create and run tests validating unit functionality before check-in.
Test automation integrated into CI/CD – In concert with upstream unit and integration testing, shift left requires downstream automation to verify stability and catch regressions. Automation at the code commit / build stage acts as an early gatekeeper to reject bad code.
QA involvement across lifecycle – To enable test creation concurrent with development, QA must engage much earlier – ideally at requirements gathering. This allows test plans to guide development, not just validate it.
Mature shift left adoption involves cultural and organizational shifts beyond just adopting modern tools and frameworks. When done effectively, cross-functional teams operate in tight iteration cycles to minimize the time bugs go undetected. The end result is more resilient code and faster delivery of value.
Shift Left Testing – Pros and Cons
Pros:
- Reduces cost to fix defects up to 100x
- Accelerates time-to-market for new features
- Increases development velocity through feedback
- Facilitates test automation and TDD/BDD adoption
- Fosters collaboration between devs and QA
Cons:
- Significant initial time investment to enable rigor
- Requires developer training on testing focus
- Additional resource requirements for QA
- Does not replace need for staging testing
Organizations implementing shift left testing realize immense benefits but must first overcome adoption hurdles. With developer buy-in and appropriate staffing, shift left testing delivers tangible improvements in release quality and velocity.
Details of Shift Right Testing
While shift left testing focuses on quality verification early in delivery cycles, shift right testing picks up post-development as code progresses closer to production deployment.
Shift right techniques that facilitate continuous testing and monitoring include:
Dark Launches – Pushing new versions to small segments of users to identify issues before broader launch. Developers gain production visibility without impacting masses.
Canary Testing – Similar to dark launches but with automated health checks. Failed canaries auto-rollback changes so developers gain feedback without hurting users.
Blue/Green Deployments – Nearly identical staging environments that switch between active and passive roles during updates. Eliminates downtime while validating production viability.
Feature Flags – Components that enable / disable functionality without re-deployment. Great for getting user feedback and A/B testing experience options.
Extensive Logging – Inclusion of verbose application and usage logs during usage. Critical for monitoring health post-deployment.
These strategies realize the promise of shift right testing – continuous quality verification and process improvement even after launch. Access to real user data informs prioritization decisions for future work.
Shift Right Testing – Pros and Cons
Pros:
- Fixes hard-to-catch issues that impact users
- Improves user satisfaction through stability
- Supports A/B testing and experimentation
- Enables progressive delivery and continuous deployment
- Fosters collaboration between QA and Operations
Cons:
- Significant production monitoring overhead
- Resource demands for logging and analysis
- Potentially disruptive to rollout marketing plans
- Dependent on Shift Left rigor to minimize issues
The benefits of shift right testing are clear, but so are challenges like overhead and risk. Still, the methodology is becoming ubiquitous for teams focused on DevOps, continuous delivery, and exceptional user experiences.
Comparing Shift Methodologies
Now that we‘ve explored shift left and shift right testing independently, let‘s compare them head-to-head:
It‘s clear each approach has distinct focus areas, from objectives to techniques to team engagement. However, combined they support unprecedented release velocity and quality:
- Shift Left establishes a quality baseline through test automation and early verification. This allows…
- Shift Right processes to refine and enhance production systems via user data…
- …Which then provides feedback to inform subsequent Shift Left testing.
Adopted together, shift left and shift right testing form a virtuous cycle of continuous improvement powered by pervasive quality verification. Issues catch early, dependencies minimize, feedback channels flourish, and users stay happy.
The key is recognizing that shift methodologies complement rather than compete. Like perfect puzzle pieces, shift left and shift right testing seamlessly interlock to drive toward DevOps actualization.
Adopting Shift Testing Within Your Organization
Of course, no two engineering organizations are identical. Teams operate under various constraints around skills, staffing, release frequency, compliance controls, and technical debt. These factors impact how – and how much – shift left and shift right testing can manifest.
Here is guidance on adoptions given common scenarios:
Lower release frequency (quarterly+): Focus shift left testing on stability via test automation and coverage analysis. Standardize environments for consistent validation. Prioritize shift right monitoring during incremental rollout to users.
Higher release frequency (weekly+): Increase shift left testing rigor through TDD/BDD paired with comprehensive CI automation. Embrace shift right testing starting with dark launches and canary analysis.
Resource constraints: Ensure shift left testing happens first to maximize stability gains. Take iterative approach scaling shift right monitoring and self-healing functionality.
Compliance controls: Align control validation with shift left testing. Utilize feature flags for shift right testing to disable functionality.
Technical debt: Prioritize shift left testing to curb accumulation of more debt. As issues surface in production monitoring, quantify time/effort to resolve through engineering process improvements.
The key is not trying to do everything at once, but instead taking an incremental approach focusing on quick wins. Delivering value visibly through shift testing builds momentum towards increasingly sophisticated implementation.
The Role of Test Environments and Real Devices
Thus far we‘ve explored the importance of broad, continuous testing across the development lifecycle. But even the most rigorous validation holds limited value if the test environments fail to replicate real-world conditions.
Access to actual user devices – whether physical or cloud-based – is foundational for effective shift left testing. Validating against real mobile and desktop environments identifies issues hidden during simulation testing. Prior to releasing changes in production, verification across 3500+ real browser and device combinations pinch hits for beta testing at scale.
This extensive test coverage is now quick and affordable via on-demand cloud testing solutions. Within minutes, developers and testers can confirm website and application behavior across endless permutations of hardware, software, and connectivity.
Such real device access catches bugs often missed in traditional QA cycles:
- Varying browser / OS versions
- Different screen sizes and resolutions
- Alternate device manufacturers
- Cellular and WiFi bandwidth constraints
- Touch gestures and interface quirks
By front-loading real device testing into continuous integration pipelines, shift left testing efficacy skyrockets. Teams benefit from environment diversity and stability prior to deployment. Subsequently, shift right monitoring becomes focused more on subjective user feedback than unexpected crashes.
In summary, access to thousands of real mobile and desktop environments amplifies the impact of shift left testing. This directly translates to higher quality software experiences for your customers.
In Closing
The benefits engineering teams realize through shift left and shift right testing are clear:
- Higher release velocity
- Lower cost of quality
- Increased production stability and uptime
- Continuous processes improvements
- Happier, more engaged users
However, be wary of implementing either approach in isolation. To achieve DevOps outcomes and deliver superb digital experiences, you need appropriate solutions across the entire software delivery spectrum.
Shift left testing builds resilient code and stable releases. Shift right testing provides production visibility and user insights. Both methodologies combined establish a foundation of quality that persists through design, development, and deployment.
So while the debate around priorities rages in some organizations, modern quality leaders agree:
Adopt shift left testing. Embrace shift right testing. Deliver better software, faster.
