Testing ↔ SDLC ↔ PDLC bridge

This document maps **testing and quality assurance** practices to the two lifecycle frameworks:

Testing ↔ SDLC ↔ PDLC bridge

Purpose

This document maps testing and quality assurance practices to the two lifecycle frameworks:

  • PDLC (Product Development Life Cycle) — "Are we building the right product?"
  • SDLC (Software Development Life Cycle) — "Are we building the product right?"
  • Testing — "Is the software correct, reliable, and fit for purpose?"

Testing is the discipline that verifies SDLC execution quality and validates that PDLC outcomes are met. Without it, both lifecycles produce artifacts that cannot be trusted.

Canonical sources: APPROACHES.md · AUTOMATION-LANDSCAPE.md (this package) · Product development lifecycle (PDLC) · Software development lifecycle (SDLC) · PDLC ↔ SDLC bridge.


Document map

Section Contents
1. The three-domain model How Testing, PDLC, and SDLC relate — scope, ownership, overlap
2. Testing across the lifecycle Testing activities mapped to PDLC P1–P6 and SDLC A–F
3. Role mapping Testing roles vs Product, Delivery, and Architecture roles
4. Artifact flow What testing produces and where it goes
5. Calibration — when to invest in testing Lightweight vs heavyweight testing by context
6. Anti-patterns Common failures when testing is missing or misapplied
7. Worked example End-to-end scenario showing testing across PDLC and SDLC

1. The three-domain model

graph TB subgraph pdlcLayer ["PDLC — Product Lifecycle"] direction LR rightProduct["Build the RIGHT product"] subgraph sdlcLayer ["SDLC — Delivery"] productRight["Build the product RIGHT"] end end testLayer["Testing — Verify correctness, validate fitness"] testLayer -->|"verification: test levels, quality gates"| sdlcLayer testLayer -->|"validation: acceptance, outcome measurement"| pdlcLayer sdlcLayer -.->|"test results, coverage data"| testLayer pdlcLayer -.->|"acceptance criteria, success metrics"| testLayer

Comparison table

Dimension Testing SDLC PDLC
Core question Is the software correct, reliable, and fit for purpose? How do we build this correctly? Should we build this at all?
Scope Verification (does it meet specs?) + validation (does it meet needs?) Requirements → design → code → test → deploy Problem validation → strategy → build → launch → grow → sunset
Primary owner QA engineer / test lead / whole team (shift-left) Engineering / delivery team Product manager / product trio
Timeline Continuous — from requirements review through production monitoring Sprint / iteration / release cycle Product lifetime (months to years)
Success metric Defect detection rate, test coverage, quality gate pass rate, escaped defects Velocity, defect rate, DORA, CI pass rate Adoption, retention, NPS, revenue
Key artifacts Test plan, test cases, test results, quality reports, traceability matrix Specs, code, tests, release notes Research synthesis, experiments, vision, metrics dashboards
Risk focus Quality risk (correctness, reliability, security, performance) Technical risk (bugs, performance, security) Market risk (desirability, viability)
Failure mode Ship buggy, insecure, or unreliable software Ship late or with poor architecture Ship the wrong thing

When one is missing

Scenario What happens
Testing without SDLC discipline Tests exist but delivery is chaotic — tests are written but not run in CI, coverage targets are set but not enforced, quality gates are defined but bypassed
Testing without PDLC Software is thoroughly tested against specifications, but nobody verified the specifications solve a real problem — high-quality software that nobody uses
SDLC without Testing Code is built and deployed but never systematically verified — escaped defects, regression surprises, production incidents, eroding trust
PDLC without Testing Product direction is validated and strategy is sound, but delivered software is unreliable — validated idea, broken execution, users churn from bugs
All three practiced Validated problems become well-specified requirements that are built correctly and verified thoroughly, delivering trustworthy software that meets measurable outcomes

2. Testing across the lifecycle

PDLC phases

Phase Testing role Key activities Outputs
P1 Discover Minimal direct involvement; may review testability of proposed concepts Testability notes (informal)
P2 Validate Prototype tester Usability testing of prototypes; feasibility spike validation; identify high-risk areas Usability test results, risk-based test scope estimate
P3 Strategize Quality planner Define quality strategy; estimate testing effort; identify non-functional requirements from success criteria Quality strategy, NFR catalog, test effort estimate
P4 Launch Acceptance gatekeeper Final acceptance testing; smoke tests in production; canary monitoring Acceptance sign-off, production smoke results
P5 Grow Outcome validator Monitor production quality metrics; track escaped defects against outcomes; regression analysis Quality dashboards, escaped defect reports, outcome validation
P6 Sunset Migration tester Test data migration; verify graceful degradation; validate sunset completeness Migration test results, sunset verification report

SDLC phases

Phase Testing role Key activities Outputs Test levels engaged
A Discover Risk assessor Identify quality risks; assess testability of proposed features; plan test strategy Risk-based test scope, testability feedback
B Specify Criteria reviewer Review acceptance criteria for testability; write behavioral contracts (Gherkin); plan test levels and scope; draft test plan Test plan, BDD scenarios, testability review notes
C Design Test architect Select automation framework; define V-level pairing (if V-Model); design test data strategy; plan contract tests Test architecture, framework selection, RTM draft
D Build Test builder Write unit tests (TDD); implement integration tests; configure static analysis; add tests to CI gates; generate AI-assisted tests Unit tests, integration tests, CI pipeline config Unit, integration
E Verify Quality gatekeeper Execute system and acceptance tests; run regression suites; perform exploratory testing; run performance/security tests; verify traceability Test execution reports, quality gate results, RTM System, acceptance
F Release Release validator Final acceptance; smoke tests in staging/production; monitor canary deployment; shift-right validation Release sign-off, smoke results, monitoring baseline Acceptance

3. Role mapping

Across the lifecycle

Phase(s) Testing role PDLC role SDLC role Archetype
P1–P2 (Discovery) Testability advisor (lightweight) PM, UX Researcher — (upstream) Demand & value
P3 (Strategize) Quality strategy definer PM, GTM Lead Owner (entering SDLC) Steer & govern
A–B (Discover, Specify) Requirements reviewer, BDD author Owner (priorities), Implementer Assure & ship
C (Design) Test architect, framework selector Implementer (architecture) Build & integrate
D (Build) Unit/integration test author, CI gate builder Implementer Build & integrate
E (Verify) System/acceptance tester, exploratory tester Implementer, QA Assure & ship
F (Release) Release validator, production monitor GTM Lead — (downstream) Assure & ship
P5 (Grow) Quality metrics analyst, escaped defect tracker PM, Data/Analytics Owner (iteration) Assure & ship

Testing vs other disciplines

Dimension Testing BA DevOps Architecture
Primary focus Verify correctness and fitness Understand and specify needs Automate delivery and operations Structure systems for quality attributes
What they give testing Acceptance criteria, requirements to trace CI/CD pipelines that execute tests Architectural boundaries that define integration points
What testing gives them Verification that requirements are implementable Quality gate results for pipeline decisions Testability feedback on architectural choices
Overlap Test design, quality assessment Requirements review, acceptance criteria CI pipeline configuration, test automation NFR verification, integration test boundaries

4. Artifact flow

BA/PDLC → Testing (inputs)

Source artifact Testing usage
Acceptance criteria (BA, SDLC Phase B) Primary input for test case design; defines "done" at the story level
Non-functional requirements (BA/Architecture, Phase B–C) Drive performance, security, and reliability test plans
Success metrics (PDLC P3) Define outcome-level acceptance thresholds for validation testing
Traceability matrix (BA) Links requirements → test cases; ensures coverage completeness
Risk assessment (BA/PM) Drives risk-based test prioritization — test high-risk areas first and deepest

Testing → SDLC (outputs)

Testing artifact SDLC usage
Test results (Phases D–E) Quality gate input — pass/fail determines whether code advances
Coverage reports (Phase D) CI gate metric — minimum coverage enforced before merge
Defect reports (Phase E) Input to Phase D rework; tracked in WBS/backlog
Test plan (Phase B–C) Governs testing scope, approach, and resource allocation
RTM (Phase B–E) Proves all requirements have corresponding test coverage

Testing → PDLC (feedback)

Testing artifact PDLC usage
Acceptance test results (Phase E) P4 launch gate — confirms product meets validated needs
Production quality metrics (P5) Input to outcome measurement — escaped defects, reliability data
Usability test results (P2) Validation evidence — prototype meets user expectations
Performance baselines (Phase E–F) P5 growth capacity — can the product handle growth targets?

5. Calibration — when to invest in testing

By initiative type

Situation Testing investment Reasoning
Greenfield product (new market) Heavy — full test strategy, shift-left practices, comprehensive automation, performance baselines High uncertainty; untested assumptions propagate expensive defects
Feature on mature product Medium — regression suite protects existing behavior; new feature tests; integration tests at boundaries Existing test infrastructure reduces marginal cost; focus on boundaries and interactions
Technical infrastructure Heavy on non-functional — performance, reliability, security, chaos testing Users are other systems; functional testing is simpler but NFR testing is critical
Bug fix / maintenance Targeted — reproduce-fix-verify cycle; add regression test for the specific defect Fix scope is small; the missing test is the primary deliverable
Prototype / spike Minimal — manual validation is sufficient; don't invest in automation for throwaway code Code will be discarded; testing effort has no long-term return

By team size and context

Context Testing approach
Solo developer TDD discipline; CI with basic quality gates; manual exploratory for UI
Small agile team (3–8) Whole-team quality; developers write unit/integration tests; shared ownership of E2E; shift-left
Medium team (8–25) Dedicated QA embedded in team; test automation engineer role; structured test plans for complex scope
Large / multi-team QA chapter or guild; test architecture standards; shared test infrastructure; contract testing across services
Regulated environment Formal test documentation (RTM, test evidence); independent verification and validation (IV&V); audit trail

The test pyramid as calibration tool

                    ╱╲
                   ╱  ╲
                  ╱ E2E╲          Few — slow, expensive, high confidence
                 ╱──────╲
                ╱  API /  ╲       Contract + integration tests
               ╱  contract ╲
              ╱──────────────╲
             ╱   Component /  ╲   Unit + component tests
            ╱     unit         ╲
           ╱────────────────────╲
          ╱  Static analysis /   ╲  Linters, SAST, type checking
         ╱   type checking        ╲
        ╱──────────────────────────╲

Invest most in the lower layers (fast, cheap, stable). Keep the E2E layer thin — only critical user journeys and smoke tests. Shift testing left to catch defects when they are cheapest to fix.


6. Anti-patterns

Anti-pattern Description Symptom Fix
Ice cream cone Inverted test pyramid — most tests are slow E2E/manual; few unit tests Slow CI pipelines (>30min); flaky tests block merges; "it works on my machine" Invert the pyramid — add unit/integration tests; replace flaky E2E with contract tests; delete redundant E2E
Testing as a phase Testing happens only after "development is done" — separate test phase at the end Late defect discovery; compressed test cycles; bugs found in UAT that should have been caught in unit tests Shift-left — QA reviews acceptance criteria in Phase B; TDD in Phase D; continuous testing in CI
Coverage theater High coverage percentage (90%+) achieved by testing trivial paths; complex logic untested Coverage target met but production defects persist; false confidence in test suite quality Risk-based testing — prioritize coverage of complex, high-risk, and frequently-changed code; measure mutation testing score
Test maintenance tax Tests are tightly coupled to implementation; every refactor breaks dozens of tests Developers avoid refactoring because "it will break too many tests"; test suite becomes a drag on velocity Test behavior, not implementation; reduce test coupling; use test doubles at appropriate boundaries
Missing acceptance tests Unit and integration tests pass, but nobody tests whether the feature meets user needs Features are "technically correct" but don't solve the user's problem; discovered only after launch Connect tests to acceptance criteria from BA/PDLC; automate acceptance tests (BDD); include exploratory testing
No production testing All testing happens pre-production; production is a black box until users report problems Surprises from production-only conditions (load, data volume, network); reactive incident response Add shift-right practices — canary releases, synthetic monitoring, chaos engineering, feature flags
QA bottleneck All testing goes through a single QA person or team; developers don't write tests QA backlog grows; releases are delayed waiting for QA; QA becomes a gate instead of an enabler Whole-team quality — developers own unit/integration tests; QA focuses on test strategy, automation architecture, and exploratory testing

7. Worked example

Scenario: A SaaS company builds a payment processing feature. The initiative flows through PDLC discovery, SDLC delivery, and testing at every stage.

P2 Validate — prototype testing

The product trio builds a Figma prototype of the checkout flow. QA reviews the prototype and flags: - Edge case: what happens when payment is declined mid-transaction? - Accessibility: color-only status indicators will fail WCAG 2.1 AA - Testability: the proposed multi-step wizard will need state management tests at each step

Artifacts produced: Testability notes (3 items), usability test plan for 6 participants.

Usability test results: 5/6 participants completed checkout in under 2 minutes. One participant confused by the address auto-complete behavior. Design updated.

P3 Strategize — quality strategy

Quality strategy defined based on P3 success metrics: - Functional: all payment methods (card, ACH, wallet) must pass end-to-end - Performance: checkout latency < 2s at P99 under expected load (1000 concurrent checkouts) - Security: PCI DSS Level 1 compliance required; penetration testing mandatory - Reliability: 99.95% uptime for payment processing; circuit breaker for payment gateway failures

Test effort estimate: 2 QA-sprints for automation setup; ongoing regression in CI.

SDLC Phase B — acceptance criteria review

QA reviews acceptance criteria for testability:

Story Acceptance criterion QA feedback
PAY-001: Card payment "User can pay with Visa, Mastercard, Amex" Add: specify test card numbers for each; add declined card scenario
PAY-002: ACH payment "User can pay via bank transfer" Add: specify bank verification flow timing; add insufficient funds scenario
PAY-003: Payment receipt "User receives receipt after payment" Add: specify receipt format; add email delivery verification; add receipt for failed payments

BDD scenarios written:

Feature: Card payment
  Scenario: Successful payment with Visa
    Given the user has items totaling $49.99 in cart
    When they enter valid Visa card details and submit
    Then the payment is processed successfully
    And they see a confirmation with transaction ID

  Scenario: Declined card
    Given the user has items in cart
    When they enter a declined card number and submit
    Then they see an error message with decline reason
    And no charge is created

SDLC Phase C — test architecture

Test architecture decisions: - Unit tests: Jest for business logic; mock payment gateway SDK - Integration tests: Testcontainers for database; WireMock for payment gateway stubs - Contract tests: Pact for payment gateway API contract (consumer-driven) - E2E tests: Playwright for critical checkout journey (3 scenarios: card success, card decline, ACH success) - Performance tests: k6 for load testing checkout endpoint - Security tests: OWASP ZAP in CI; manual penetration test pre-launch

SDLC Phase D — test implementation (shift-left)

TDD for payment processing logic: - 47 unit tests covering card validation, amount calculation, retry logic, idempotency - 12 integration tests covering database transactions, gateway communication, webhook handling - 3 contract tests (Pact) verifying payment gateway API compatibility - Static analysis: ESLint, TypeScript strict mode, SonarQube quality gate

CI pipeline quality gates: all tests must pass; coverage > 80% on new code; SonarQube quality gate pass; no critical/high security findings.

SDLC Phase E — verification

  • System tests: Full checkout flow against staging environment with test payment gateway
  • Performance test: k6 load test — 1000 concurrent checkouts, P99 latency 1.4s (target: < 2s) — passed
  • Security test: OWASP ZAP scan — 0 high findings, 2 medium findings (fixed before release)
  • Exploratory testing: QA explores edge cases — discovers that double-clicking "Pay" creates duplicate charges; filed PAY-BUG-001, fixed in Phase D rework
  • Acceptance testing: BDD scenarios all green; PO reviews and accepts
  • RTM: All 7 requirements traced to test cases; all test cases passed

P4 Launch — production validation

  • Canary deployment: 5% of traffic routed to new payment flow; monitoring for error rates, latency, conversion rate
  • Smoke tests: 3 critical checkout scenarios automated in production (synthetic monitoring)
  • Results after 24h: 0 errors, P99 latency 1.6s, conversion rate +2.1% vs control

P5 Grow — outcome validation

Week 4 metrics:

Metric Target Actual Status
Checkout completion rate 85% 87% Exceeded
Payment processing latency (P99) < 2s 1.5s Met
Payment failure rate < 1% 0.4% Met
Escaped defects (production) 0 critical 0 critical, 1 low Met

Escaped defect: Low-severity formatting issue in receipt PDF for amounts > $10,000 (comma placement). Regression test added.

Quality feedback to SDLC Phase A: "Add currency formatting unit tests for large amounts" — new story created in iteration backlog.


Doc Why
APPROACHES.md Test levels, types, techniques, strategies, ISTQB alignment
AUTOMATION-LANDSCAPE.md Framework taxonomy, selection guidance, cloud infrastructure
PDLC ↔ SDLC bridge How PDLC and SDLC relate without the testing lens
Software development lifecycle (SDLC) Delivery phases A–F, DoD, CI/CD quality gates
Product development lifecycle (PDLC) Product phases P1–P6, stage gates, outcome metrics
Test plan — [scope] Copy-paste template for scope-level test plans
V-Model — deep-dive package (blueprint) V&V pairing; RTM; formal test gates
methodologies/bdd.md Behavior-driven development; Given-When-Then; living specs