Why Tests Passing Is Not the Same as Closure

15 functions that pass every test. All 15 are wrong. BRIK64 catches them all — without running a single additional test.

Your Tests Pass. Your Code Is Still Wrong.

Green test suite. 100% coverage. Code review approved. Ship it. Everyone goes home happy.

Except the function that rounds prices has a floating-point comparison that fails for exactly one value in ten thousand. The accumulator that sums transaction amounts silently overflows after 2,147,483,647 cents. The string parser handles every test case perfectly — unless the input is exactly 255 characters long, at which point it truncates silently and returns a valid-looking but wrong result. These are real bugs in real production systems.

Tests verify specific inputs. They cannot verify all inputs. And the bugs that matter most — the ones that cost millions, the ones that bring down banks — are the ones hiding in the inputs nobody thought to test.

15 Functions. 15 Hidden Bugs. Zero Test Failures.

We assembled 15 real-world functions — pricing calculations, data validators, string formatters, accumulator patterns — each with a comprehensive test suite. Every single test passes. Every single function contains a bug that the tests miss.

BRIK64's TCE catches all 15. Not by running more tests — by operating on the mathematical structure of the computation itself. Other tools ask: "does this work for these inputs?" The TCE asks: "is this circuit closed for all inputs within the declared domain?" Different question. Completely different answer.

See for Yourself

The full demo — all 15 functions, their passing test suites, the specific inputs that trigger each bug, and the TCE diagnostics — is available to run locally:

git clone https://github.com/brik64/brik64-demos.git
cd brik64-demos
./run_demo.sh demo3-error-elimination

For the complete technical breakdown of each bug category and reproduction steps:

View all demos on Digital Circuitality →

Your tests pass. That is necessary. It is not sufficient. Tests check examples. Certification checks structure. Φ_c = 1 means correct for all inputs — not the ones you thought of, all of them. Stop testing. Start certifying.