testingembeddedsafety

Bridging Timing Analysis to Functional Tests: A Unified Strategy with RocqStat Integration

UUnknown

2026-02-03

9 min read

Combine RocqStat WCET with unit/integration tests to create gateable, auditable release criteria for safety-critical software.

Bridging Timing Analysis to Functional Tests: A Unified Strategy with RocqStat Integration

Hook: As safety-critical teams push for faster release cycles in 2026, unpredictable execution times and late-stage timing surprises remain top release blockers. You can avoid costly rework and missed schedules by combining rigorous WCET timing analysis from RocqStat with your existing unit and integration tests to create deterministic, testable release gates.

Why this matters now (2026 context)

Late 2025 and early 2026 saw two clear trends shaping verification strategy for safety-critical software: a sharp rise in the adoption of statistical timing tools and consolidation of verification toolchains. In January 2026 Vector Informatik announced the acquisition of StatInf's RocqStat and plans to integrate it into the VectorCAST toolchain — a sign that timing analysis is moving from a specialized niche into mainstream CI/CD workflows for automotive, aerospace, and industrial systems.

"Vector will integrate RocqStat into its VectorCAST toolchain to unify timing analysis and software verification" — Automotive World, Jan 16, 2026.

For teams building safety-critical systems (ISO 26262, DO-178C, IEC 61508), this means timing constraints are no longer separate artifacts. Organizations must adopt unified test strategies that validate both functional correctness and timing correctness before release gating decisions.

Core idea: unify WCET results with functional tests for gateable evidence

The unified strategy has three pillars:

Deterministic timing budgets derived from RocqStat WCET estimates (statistical + static measurements).
Functional test coverage (unit, integration, system) that exercise the same control paths used for timing estimation.
CI/CD gating logic that fails builds when timing budgets or functional correctness fall outside accepted thresholds.

Benefits you'll realize

Reduce last-minute rollbacks due to missed real-time requirements.
Create auditable, traceable release evidence for safety certification.
Shorten verification cycles by running timing checks as part of normal CI, instead of expensive offline analysis only.

How RocqStat complements functional testing

RocqStat brings advanced statistical WCET estimation and timing analytics that handle modern multi-path code and complex hardware profiles. When integrated into a functional-testing pipeline:

RocqStat provides timing budgets per function or task that become pass/fail criteria for tests.
It correlates dynamic trace data with worst-case scenarios so your integration tests can validate observable execution times under representative inputs.
It supports confidence levels (e.g., 1e-6 probability of exceeding WCET) — necessary for safety arguments.

Practical strategy: map WCET to tests

Follow this step-by-step approach to integrate RocqStat WCET into your testing pipeline.

1. Scope and partition

Identify timing-critical components (e.g., control loops, schedulable tasks). Partition code into:

Hard real-time functions (must meet WCET under all conditions)
Soft real-time functions (graceful degradation acceptable)
Non-timing functions (no hard constraints)

2. Generate WCET estimates with RocqStat

Instrument representative builds and feed traces to RocqStat for statistical WCET estimation. For safety-critical assurance, document confidence levels and environmental assumptions (CPU frequency, cache state, multicore interference settings).

3. Create timing-aware test cases

For each functional test (unit/integration/system) tie the test to timing budgets. Use the same input vectors or mocks used to generate traces. For example:

// Unit test pseudo-code: verify functional output and timing
assertEquals(expected, compute_control(signal));
assertTrue(measured_time(&compute_control) < WCET_budget_ms);

4. Run timing checks in CI

Integrate RocqStat as a CI step (see example pipelines below). Execute tests on representative hardware or hardware-in-the-loop (HIL) to capture realistic timing. Use virtualization only if you can reproduce timing characteristics deterministically.

5. Gate releases on combined criteria

Define release gates that require both:

Functional tests: pass at target coverage thresholds (e.g., 95% MC/DC or required line/branch coverage).
Timing tests: WCET budgets met at specified confidence levels (e.g., 1e-6).

CI/CD patterns and sample configurations

Below are practical CI examples to run RocqStat WCET steps and fail fast if timing or functional criteria fail. Use them as templates for Jenkins, GitLab CI, or GitHub Actions.

Example: GitLab CI job

stages:
  - build
  - test
  - timing

build-job:
  stage: build
  script:
    - make all

unit-tests:
  stage: test
  script:
    - ./run_unit_tests.sh --report junit.xml
  artifacts:
    when: always
    reports:
      junit: junit.xml

wcet-analysis:
  stage: timing
  script:
    - ./deploy_to_test_hardware.sh
    - ./collect_traces.sh --duration 60s --output traces.bin
    - rocqstat analyze --input traces.bin --config rocq_config.yaml --output wcet.json
    - ./evaluate_wcet.py wcet.json --thresholds thresholds.yaml
  allow_failure: false
  artifacts:
    paths:
      - wcet.json

The key: make the wcet-analysis job non-optional for release branches so timing failures block merges.

Example: Jenkins pipeline groovy snippet

pipeline {
  agent any
  stages {
    stage('Build') { steps { sh 'make' } }
    stage('Unit') { steps { sh './run_unit_tests.sh' } }
    stage('WCET') {
      steps {
        sh './deploy_to_hil.sh'
        sh './collect_and_run_rocqstat.sh --out wcet.json'
        sh 'python3 verify_wcet_gate.py wcet.json --max-ms 5.0'
      }
    }
  }
}

Defining gating logic: measurable and auditable

A release gate needs precise rules. Use machine-checkable predicates with human-readable audit records.

Functional gate: Unit and integration tests pass; code coverage >= threshold; all blocker-level defects closed.
Timing gate: For each monitored function f, measured WCET(f) <= WCET_budget(f) at confidence c (documented). If RocqStat reports an exceedance probability > allowed threshold (for example, > 1e-6), the job fails.
System gate: End-to-end latency and schedulability checks (e.g., response time analysis) pass under worst-case task interference models.

Example policy snippet (release.md)

Timing Gate Policy
- All hard real-time tasks: ROCQ_WCET_CONFIDENCE = 1e-6
- Measured WCET <= Budget
- If any WCET_exceedance_prob > 1e-6, block release and open ticket

Combining static, measurement-based, and statistical methods

No single method suffices for modern multicore and mixed-criticality systems. Combine:

Static WCET analysis (path-level reasoning) for conservative upper bounds where possible.
Measurement-based timing to capture real hardware behavior and platform-specific effects.
Statistical analysis (RocqStat) to provide probabilistic WCET with confidence levels, making tradeoffs between safety margin and over-conservatism.

Use RocqStat to reconcile measured traces with path models and to produce WCET distributions. That distribution then becomes the basis for your CI gating thresholds rather than single-point measurements.

Case study (hypothetical): ECU control loop

Scenario: An automotive ECU runs a control loop every 10 ms. Historically developers tested only functional correctness and observed execution times under light load. Late-stage testing discovered rare cases where execution spiked near 9.7 ms causing sporadic missed deadlines under peak workload.

Unified approach applied:

Instrumented control function across representative inputs and disturbance scenarios; collected 10k traces on real ECU hardware.
Processed traces with RocqStat to compute a 1e-6 WCET of 9.85 ms (90% confidence threshold analysis produced actionable results).
Updated functional integration tests to assert both output correctness and measured execution <= 9.85 ms across sampled inputs.
Added a CI wcet-analysis job running nightly against hardware-in-the-loop; PR builds run a subset of timing tests on a simulated environment with a higher margin.
Release gate: any PR that introduces an increase >0.1 ms in a task's WCET requires a safety review and mitigation plan.

Outcome: Early detection of code changes that expanded critical path latency and an auditable trail for certification.

Multicore and interference: what to watch for

In 2026, multicore ECUs are pervasive and present two timing risks:

Shared resource interference (cache, memory bus) can inflate WCET unpredictably.
Co-scheduled workloads from mixed-criticality tasks can cause transient spikes.

Mitigations when integrating RocqStat:

Collect traces with representative co-runners enabled (HIL or synthetic load generators).
Use isolation strategies (partitioning, time-partitioned scheduling) and validate those strategies with measurement-backed WCET evidence.
Document environmental assumptions in your WCET artifacts (CPU freq, partitioning, interference models).

Metrics, dashboards, and audit artifacts

Operate timing and functional verification as observable services. Essential artifacts to store and link from CI results:

WCET report (rocqstat output) with confidence metadata.
Execution trace samples (anonymized if needed) used for analysis.
Test results (unit/integration) and coverage reports.
Release gate decision record (who approved exceptions, ticket links).

Expose trends on dashboards: weekly WCET deltas, per-function percentile shifts, and PR-level timing impact. Use alerts for regressions exceeding policy thresholds. Ensure you store and link from CI results in a resilient archive that supports certification audits.

Pitfalls and pragmatic mitigations

Pitfall: Running RocqStat only offline. Fix: Integrate into CI with representative hardware sampling and nightly full runs.
Pitfall: Loose mapping between tests and timing paths. Fix: Link test vectors to path IDs used by RocqStat and enforce test maintenance rules.
Pitfall: False confidence from simulated environments. Fix: Validate simulations against hardware traces and mark simulated runs as advisory.

Checklist for implementing a unified timing + functional test strategy

Identify timing-critical tasks and define WCET budgets.
Instrument and collect representative traces on target hardware.
Run RocqStat analysis and record confidence levels and assumptions.
Associate unit/integration tests with timing budgets and create timing assertions.
Integrate RocqStat and timing jobs in CI; ensure gating is non-optional for release branches.
Create dashboards and store audit artifacts for certification evidence.
Automate alerts and require mitigation plans for regressions; consider using automated workflow patterns to trigger runbooks and notifications.

Future trends and predictions (late 2025 — 2027)

Expect the following in 2026–2027:

Tool consolidation: more analysis engines (like RocqStat) integrated into mainstream testing suites (VectorCAST) enabling single-pane-of-glass verification flows.
Regulatory emphasis on timing assurance: certification bodies will expect probabilistic timing evidence where appropriate, and CI evidence will be part of DO-178C and ISO 26262 submissions.
ML-assisted timing regression detection: automatic PR-level estimations of timing delta and risk scoring.

Final takeaways — actionable guidance

Treat WCET as code-level quality: integrate RocqStat outputs into PR checks and code review criteria.
Run representative hardware traces: statistical WCET is only as good as the input data; instrument, observe, and validate end-to-end (see guidance on observability patterns).
Make gates measurable: machine-checkable predicates for timing and function avoid human error and speed approvals.
Document everything: assumptions, confidence levels, and environment descriptions are critical for audits and certification.

Combining timing analysis (WCET) with functional test results is not optional for modern safety-critical development — it's the most efficient path to reliable, auditable releases that regulators and customers can trust.

Call to action

If you're ready to harden your release gates with timing-backed evidence, start with a two-week pilot: pick a timing-critical module, collect traces on target hardware, run RocqStat, and add timing assertions to your unit tests. If you want a template CI integration or help constructing gating policies tailored to ISO 26262 / DO-178C objectives, contact our team for a workshop and a sample pipeline tuned to your toolchain.

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