Senior Software Tester (Python, AI/LLM Pipelines)

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Leudelange, Luxembourg

  1. Sopra Steria
  2. Standard
  3. Leudelange
  4. Infrastructure & Cloud
  5. No
  6. Mid-Senior Level

Company Description

Sopra Steria is Europe’s leading digital solutions provider, employing over 56,000 employees in 30 countries. We provide tailored, end-to-end corporate technology and software solutions. We leverage our digital tools and market expertise to help our clients make bold choices and deliver results. Our commitment to innovation, collaboration and value in business development is why we’re the preferred technology partner of Europe’s most successful companies. The world is how we shape it, so let’s shape it together.


Job Description

We are looking for a Senior Software Tester with 10+ years of experience in testing Python-based backend systems, AI/LLM pipelines, API layers, and automated testing infrastructures.
You will own the quality lifecycle end-to-end, from API entrypoints to full AI pipeline validation, helping ensure reliability, performance, and observability across production-grade systems.

This role is intended for an expert tester capable of working autonomously, designing advanced automation strategies, and guiding teams in best practices for resilience, observability, and continuous validation.

Key Responsibilities

1. Testing & Quality Assurance

  • Design, implement, and maintain automated test suites using pytest (fixtures, parametrization, asyncio).
  • Build end-to-end test coverage across UI, API layers, backend services, and AI/LLM pipelines.
  • Implement browser and API E2E testing using Playwright.
  • Develop contract and integration tests for REST and gRPC services.
  • Detect and remediate flaky tests, ensuring long-term stability.
  • Perform failure-injection testing (timeouts, malformed payloads, empty-response handling).
  • Validate auth flows: SSO, OAuth2, token-based access.

2. Backend & Infrastructure Testing

  • Deep testing experience with Python systems: async patterns, package design, CLI tooling.
  • Validate backend services built with FastAPI or equivalent.
  • Work with containerized environments (Docker) and Kubernetes-based E2E topologies mirroring production.
  • Integrate and validate CI/CD flows using GitHub Actions or GitLab CI.

3. Observability & Metrics

  • Implement and validate OpenTelemetry instrumentation (traces, logs, metrics).
  • Build latency and SLO/SLA assertions directly into test suites.
  • Use Jaeger, Grafana, or similar platforms to analyse distributed traces and test regressions.
  • Produce trace-based regression reports for AI pipeline executions.

4. End‑to‑End Ownership

  • Ensure full lifecycle coverage from API trigger → backend logic → AI pipeline → validated output.
  • Maintain containerized E2E test environments.
  • Ensure reproducibility and alignment with production architecture.

Expected Deliverables

  • Automated test suites achieving ≥80% critical-path coverage.
  • Comprehensive E2E test plans covering core user journeys, edge cases, and failure modes.
  • Trace-based regression analysis for AI/LLM workloads.
  • Documentation:
    • Testing strategies
    • Test case catalogues
    • Execution reporting

Qualifications

Technical Skills

  • 10+ years Python development/testing (async, REST/gRPC, CLI tooling).
  • pytest ecosystem mastery (fixtures, parametrization, asyncio).
  • Playwright for UI/API E2E testing.
  • Kubernetes, Docker, containerized test environments.
  • Observability tooling (OpenTelemetry, Jaeger, Grafana).
  • CI/CD: GitHub Actions, GitLab CI.
  • Knowledge of LLM/AI pipelines is a key asset.

Professional Skills

  • Excellent documentation and communication abilities.
  • End-to-end problem solving and autonomy.
  • Strong analytical skills and root-cause investigation capability.
  • Ability to collaborate with architects, developers, and data teams in distributed environments.

Nice to Have

  • Experience with Agile methodologies.
  • Experience working with EU Institutions is a strong plus.
  • Experience with Atlassian Suite (Jira, Confluence).

Additional Information

As a member of one of Europe’s largest digital solutions providers, you’ll benefit from extensive career development opportunities, both local and international. At the Sopra Steria Academy, you’ll be part of a dynamic network of 56,000 professionals at all stages of their careers. With a wide array of offices to explore, you can find your ideal location and take the next step in your career.

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Sopra Steria is an equal opportunity employer. All qualified applicants will be considered for employment without regard to age, ancestry, nationality, color, family or medical leave, gender identity or expression, genetic information, immigration status, marital status, medical condition, national origin, physical or mental disability, political affiliation, protected veteran or military status, race, ethnicity, religion, gender (including pregnancy), sexual orientation or any other characteristic protected by applicable local laws, regulations and ordinances. We foster a work environment that is inclusive and respectful of all differences.

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