Test efficiency

Our automated test suite is fast, reliable, and free of flaky tests.

What is test efficiency?

Test efficiency refers to having an automated test suite that runs quickly, produces consistent results, and doesn't suffer from intermittent failures (flaky tests). Efficient tests give developers fast, reliable feedback on their changes without unnecessary waiting or false alarms, enabling higher productivity and confidence in the codebase.

An efficient test suite is characterized by: - Fast execution times that don't disrupt developer flow - Reliable, consistent results across multiple runs - Absence of flaky tests that pass and fail unpredictably - Appropriate resource usage (CPU, memory, network) - Good coverage with minimal redundancy

How does test efficiency impact developer experience?

It Preserves Developer Flow State

When tests run quickly, developers maintain their focus and momentum. Long-running tests force context switching, which destroys productivity and satisfaction.

As one developer noted:

"We regularly face challenges with build times, particularly on larger projects and subsidiary repositories. This creates a slower feedback loop for developers, which is a significant pain point. The typical scenario is that you submit a pull request, then have to wait 30 minutes to an hour for the build to complete while it runs all the necessary tests and processes."

Chief API Officer at Digital Banking Software Provider

It Reduces Wait Times and Frustration

Fast, reliable tests minimize the time developers spend waiting for feedback, allowing them to iterate quickly and maintain momentum.

One engineering leader observed this impact directly:

"We identified issues with our pipelines and test workflows. This gave us a specific area to investigate. Our priority became fixing these problems across the organization to prevent developers from wasting valuable time waiting for builds and tests to complete."

Director of Engineering at Networking and Communications Company

It Builds Trust in the Development Process

When tests are reliable and not flaky, developers trust their feedback and make decisions with confidence. Flaky tests erode this trust and can lead to developers ignoring test results altogether.

It Accelerates Delivery Cycles

With efficient tests, teams can release more frequently with confidence, speeding up the overall delivery process.

Why is test efficiency important?

Test efficiency is a critical factor for successful development teams because:

It's a productivity blocker when absent

"In our analysis of the team's key roadblocks based on actual data, test efficiency emerged as the number one challenge. This provides an important insight."

Global Head of DevOps at Software Development Company

It directly impacts developer satisfaction: Long build and test times create frustration and context switching.

It affects quality and confidence: When tests are slow or unreliable, developers may skip running them locally, leading to more issues being discovered later in the process.

It enables rapid experimentation: Efficient tests allow teams to try new approaches with quick feedback, fostering innovation.

It's a competitive advantage: Teams with efficient test suites can ship features faster and respond more quickly to market needs.

How to measure test efficiency in a simple way?

The Network Perspective DevEx Survey addresses test efficiency directly with the statement:

"Our automated test suite is fast, reliable, and free of flaky tests."

This single question effectively captures multiple dimensions of test efficiency: - Speed (is the test suite fast?) - Reliability (do tests consistently produce the same results?) - Stability (are tests free from flaky behavior?)

Developer responses to this question can quickly reveal whether test efficiency is a problem area for your team. Consistently low scores indicate that your test infrastructure may be hindering productivity.

Some organizations supplement this with more specific metrics:

"The second metric we gather is about test reliability. Specifically, we ask developers: 'How frequently did you encounter flaky tests during the past quarter?' This forms our second key question in this category of assessment."

Professional

Common test efficiency problems and solutions

Our tests are too slow. How can we speed them up?

Slow tests are one of the most common developer experience complaints. Here are practical approaches to address this:

Identify the slowest tests and optimize them first - Use test runners that report execution times - Focus on the 20% of tests that consume 80% of the time

Parallelize test execution - Run tests across multiple cores or machines - Group tests intelligently to maximize parallelization benefits

Implement proper test isolation and setup - Use appropriate test doubles (mocks, stubs) instead of actual dependencies - Create focused unit tests that don't rely on complex environments

Optimize test data and environment setup - Use in-memory databases for tests instead of actual databases - Implement intelligent fixtures that minimize setup/teardown costs

Consider test pyramids - Ensure you have more fast unit tests than slow integration or end-to-end tests - Reserve slow tests for critical paths only

A developer shared how slow nightly tests impacted their work:

"During our nightly processes, we run comprehensive testing, which contributes significantly to our build time challenges. The situation becomes particularly problematic when a rebuild is required during these nightly tests - it essentially causes all tests to fail. This was actually the primary factor that highlighted our unsustainable build times and prompted us to address the issue."

Director of Software Engineering at Mobile Games Developer and Publisher

How do we eliminate flaky tests in our suite?

Flaky tests—those that pass and fail inconsistently—destroy developer trust in the test suite. Here are strategies to address them:

Systematically identify and track flaky tests - Log and monitor tests that fail intermittently - Create a dedicated process for addressing flaky tests

Isolate test environments completely - Ensure tests don't share state or resources - Reset the environment between test runs

Address timing issues - Avoid hard-coded waits; use proper synchronization mechanisms - Implement retry mechanisms for network-dependent tests

Fix or quarantine flaky tests immediately - Don't let flaky tests persist in your main suite - Move persistently flaky tests to a separate suite until fixed

Consider deterministic alternatives - Replace end-to-end tests with more stable integration tests where possible - Use contract tests instead of direct service integration tests

How can we make our CI/CD pipeline more efficient?

An efficient CI/CD pipeline is critical for quick feedback. Consider these approaches:

Implement test splitting and parallelization - Distribute tests across multiple runners - Use intelligent test selection based on affected code

Use incremental testing strategies - Only run tests affected by code changes - Implement test impact analysis to prioritize tests

Optimize the build process - Use build caching effectively - Optimize Docker image sizes and build steps

Consider cloud-based CI solutions - Scale resources dynamically based on demand - Use specialized infrastructure for different test types

Create fast feedback loops with multi-stage pipelines - Run quick tests first, slower tests later - Fail fast on basic issues before running expensive tests

Here's an approach that demonstrates an efficient environment setup:

"We provide each developer with their own dedicated cloud-based development environment. They can launch this environment in approximately a minute, and the cost per environment is quite reasonable. Additionally, every developer can quickly spin up a sandbox environment within the same timeframe and run their tests in that isolated space."

Director of Engineering at Software Development Company

How do we balance test coverage with test efficiency?

Finding the right balance between comprehensive testing and test speed is challenging. Here's how to approach it:

Adopt a test pyramid approach - More unit tests (fast, focused) - Fewer integration tests (medium speed, medium scope) - Minimal end-to-end tests (slow, broad scope)

Focus on critical paths and business logic - Identify the most important user journeys and heavily test those - Prioritize testing business-critical code over boilerplate

Use code coverage wisely - Target high coverage for critical components - Accept lower coverage for stable, low-risk areas

Implement risk-based testing - Allocate more testing resources to high-risk, frequently changing code - Use lighter testing for stable, low-risk components

Consider test-driven development (TDD) - Writing tests first often leads to more testable, modular code - TDD tends to produce focused tests that run faster

A team described their approach to balancing test coverage and efficiency:

"We began embracing the mentality that automation should be part of our initial thought process. However, we first needed to address fundamental issues like branching problems, developers lacking proper tools, and insufficient continuous delivery systems. After resolving these basics, we could focus on improving our testing quality and overall approach. That's when we introduced elements of Test-Driven Development, though not strictly following the textbook definition. We aim to incorporate unit tests during the first release, encouraging developers to consider testing while writing code. So while they're building features, they're simultaneously implementing tests—it's not orthodox TDD, but a practical adaptation that works for our context."

Head of Engineering at Technology Company

The business case for investing in test efficiency

Improving test efficiency requires investment, but the returns are substantial:

Increased developer productivity - Less time waiting means more time coding - Reduced context switching preserves focus and flow

Faster time to market - Quicker feedback cycles enable faster iterations - More reliable deployments reduce production issues

Improved code quality - Developers run tests more frequently when they're fast - More confidence in refactoring leads to better code maintenance

Enhanced developer satisfaction and retention - Developers strongly prefer working with efficient test infrastructure - Test inefficiency is frequently cited as a source of frustration

Reduced infrastructure costs - Efficient tests consume fewer computing resources - Faster pipelines mean less CI/CD infrastructure needed

Companies track these metrics closely:

"We're tracking build duration metrics. At the organizational level, we analyze developers' build cycles, deployment frequency, and build times. These metrics help us gauge the complexity of our systems and processes."

CTO at IT Services Company

Conclusion

Test efficiency is not merely a technical concern—it's a fundamental aspect of developer experience that directly impacts productivity, quality, and satisfaction. As revealed in our research across hundreds of teams, test efficiency is often identified as a critical roadblock:

"The test efficiency metrics here are truly concerning."

Financial Director at Software Development Company

By measuring and improving the speed, reliability, and stability of your test suite, you create an environment where developers can work confidently at their highest potential.