8 posts
Your unit tests check specific inputs. Symbolic execution checks every possible input. Here's how it works, what it costs, and where to start.
Your test suite has 94% coverage and zero failures. A symbolic execution engine finds a crash in your code in under three seconds. The test is not broken. The…
Metamorphic testing has uncovered real bugs in GCC, LLVM, Vulkan shader compilers, and ADAS simulators.
Metamorphic testing has found 147 confirmed bugs in GCC and LLVM, defects in commercial ADAS simulators used by automotive OEMs, and a fatal flaw in a…
Not all metamorphic relations catch bugs. Weak relations give false confidence while strong ones find real faults.
You wrote twelve metamorphic relations for your pricing engine. Every test passes. You feel good about your coverage. Then a customer reports that bulk…
Metamorphic testing lets you verify code correctness without knowing the exact expected output.
You ship a machine learning model that labels support tickets. Your test suite is green. Every test passed. None of those tests actually check whether the…
Literate programming keeps documentation, tests, and implementation in sync by making a Markdown file the single source of truth.
Your docs, tests, and code are three files telling the same story badly. You update the function signature in the source. You forget the README example. A week…
Why model checking beats days of production runtime for finding concurrency bugs, and how to apply it to your own code.
Waiting for race conditions to surface in production is not testing. It is hope dressed up as diligence. You can run your app for weeks, watch your metrics…
Mocked database tests verify your SQL syntax, not whether rows survive crashes, concurrent writes, or schema mismatches.
If you mock your database in tests, you are testing that your repository layer calls the right methods. You are not testing that data survives a crash, that a…
Mocking every Redux action turns your tests into a changelog validator. Here's how to test your store with real state transitions instead.
If you have ever written a test that verifies was called with the exact payload shape, you have written a test that breaks every time someone renames a…