TDD Consultant & Systems Engineer

Tests first. Ship with confidence.

I help engineering teams build correctness into the foundations -- from property-based tests to full TDD adoption across Go, Erlang/OTP, and financial systems.

go test ./... -v
$ go test ./ledger/... -race -count=1
--- Running suite: LedgerSuite ---
TestDoubleEntry_Balanced     1.2ms
TestTransaction_Idempotent   0.8ms
TestAuditLog_Integrity      2.1ms
TestCurrency_NoFloatLeakage  0.4ms
TestRollback_OnPartialFail   3.7ms
PropTest_MonotonicBalance    18ms
 
PASS  6/6  coverage: 97.4% of statements
$
10+
Years in Production Systems
97%
Avg. Coverage Target
0
Float Arithmetic in Finance Code
Refactors Made Safe by Tests

What I deliver

TDD-01

TDD Coaching & Team Adoption

Embedded mentorship and structured workshops to shift your team from test-last to test-first. I work alongside your engineers until the habit sticks -- covering red-green-refactor cycles, test boundary design, and fixture strategies.

WorkshopsPairingCode ReviewGo
ARCH-02

Architecture & Design Review

ADR-driven design sessions to catch architectural flaws before they calcify. Includes testability audits -- identifying seams where dependencies should be abstracted to enable clean unit and integration testing.

ADRsDomain ModelingTestability
FIN-03

Financial Systems Engineering

Correctness-first consulting for core banking, double-entry ledgers, and payment infrastructure. Integer arithmetic, idempotency proofs, and regulatory audit trails built in from day one -- not bolted on after.

Ledger SystemsErlang/OTPPCI-DSS
PBT-04

Property-Based Testing

Go beyond happy-path examples. I introduce PropEr, rapid, and custom generators that stress your invariants across thousands of inputs -- exposing edge cases that example tests never reach.

PropErHypothesisFuzzingInvariants
OTP-05

Erlang/OTP Systems

Fault-tolerant system design using OTP supervision trees, Common Test suites, and "let it crash" philosophy -- hardened with full integration test coverage and production-grade release management via Rebar3.

ErlangOTPCommon TestRebar3
AGT-06

Agent-Driven Development

Structured prompt engineering and multi-agent pipeline design to accelerate delivery without sacrificing correctness. Proof-of-execution gates ensure AI-generated code meets the same TDD bar as human-written code.

AI WorkflowsPrompt Eng.TDD Gates

How it works

01

Discovery & Audit

I read your codebase before I say a word. Coverage reports, test quality, architecture patterns -- a full testability audit with documented findings.

02

Design & Planning

Architectural decisions documented as ADRs. A phased testing strategy with measurable goals and clear definitions of done.

03

Embedded Execution

Paired sessions, PR reviews, and iterative delivery. Every feature ships test-first, with verification gates you can run yourself.

04

Handoff & Sustain

Documentation, runbooks, and coaching that outlasts the engagement. Your team owns the practice when we are done.

Built for
hard problems

A decade of production engineering across financial infrastructure, distributed systems, and compiler-adjacent tooling. Every line of code I deliver comes with a test that proves it works -- and a refactor path that proves it is maintainable.

Go
Erlang / OTP 25
WebAssembly
C
PostgreSQL
Mnesia
PropEr / Common Test
Docker/K8s
SUITE: iron_ledger_SUITEALL PASSING
init_per_suite✓ ok0.3ms
double_entry_balance_check✓ ok1.4ms
concurrent_transfer_safety✓ ok14.2ms
supervisor_restart_strategy✓ ok5.1ms
prop_monotonic_credits✓ ok22ms
idempotency_on_retry✓ ok2.9ms
audit_log_tamper_detect✓ ok1.1ms
rollback_on_constraint✓ ok3.6ms
8 passed  ·  0 failed  ·  0 skipped51ms total

Engineering principles

"A test suite that doesn't fail when the code is wrong isn't a safety net -- it's a false sense of security."
On test integrity
"Read the codebase before you touch it. Architecture decisions made blind become debt that compounds forever."
On discipline
"Integer arithmetic is not optional in financial code. Floating point errors compound. So do the lawsuits."
On correctness
"The best documentation is a test that fails when behavior changes -- and a human-readable name that says why."
On communication

Let's build
something solid

Taking on select consulting engagements. Whether you need a full TDD transformation or a focused architecture review, I'm happy to scope it out.