Defunctionalise your continuations and your tests can run any computation a step at a time.
Ephemeral testing
We have many ways to ensure software quality. Unit testing. Fuzz testing. Integration testing. And so forth. I'd like to propose a method that was unthinkable before: ephemeral testing. (Ephemeral is a fancy word for 'throw away' or 'temporary'.) You write your code. You build your software component. Or the AI agent does … Continue reading Ephemeral testing
Hypothesis: A new approach to property-based testing
The property-based testing library for Python
Call-by-name, call-by-value and the λ-calculus
This paper examines the old question of the relationship between ISWIM and the λ-calculus, using the distinction between call-by-value and call-by-name. It is held that the relationship should be mediated by a standardisation theorem. Since this leads to difficulties, a new λ-calculus is introduced whose standardisation theorem gives a good correspondence with ISWIM as given by the SECD machine, but without the letrec feature. Next a call-by-name variant of ISWIM is introduced which is in an analogous correspondence withthe usual λ-calculus. The relation between call-by-value and call-by-name is then studied by giving simulations of each language by the other and interpretations of each calculus in the other. These are obtained as another application of the continuation technique. Some emphasis is placed throughout on the notion of operational equality (or contextual equality). If terms can be proved equal in a calculus they are operationally equal in the corresponding language. Unfortunately, operational equality is not preserved by either of the simulations.
Antithesis: autonomous software testing
Try the Antithesis autonomous testing platform and find bugs in your software with perfect reproducibility
Testing functional UIs - Hayleigh Thompson | Lambda Days 2025
All the ways to mock your Rust code
Ok, so, suppose you’ve written a Kubernetes controller, you did it in Rust, and then you realized that “Hey, when this thing breaks it’s hard to understand what’s going on”. So, you decide to emit some Kubernetes events that give a little more context as to what your controller is doing and what steps it’s taken. You run all your tests
Hypothesis, Antithesis, synthesis
Introducing Hegel, our new family of property-based testing libraries.
Readable Robot Tests: Bridge the Tech Gap
A walkthrough of the Robot Testing pattern in Flutter, an end-to-end technique that keeps tests readable for non-technical stakeholders and reusable as code grows.
A new era for software testing - <antirez>
Putting Paradoxes to Work: Contextuality in Measurement-Based Quantum Computation
We describe a joint cohomological framework for measurement-based quantum computation (MBQC) and the corresponding contextuality proofs. The central object in this framework is an element $$[\beta _\Psi ]$$[βΨ]in the second cohomology group of the chain complex describing a given MBQC. $$[\beta _\Psi ]$$[βΨ]contains the function computed therein up to gauge equivalence, and at the same time is a contextuality witness. The present cohomological description only applies to temporally flat MBQCs, and we outline an approach for extending it to the temporally ordered case.
WiCER: Wiki-memory Compile, Evaluate, Refine Iterative Knowledge Compilation for LLM Wiki Systems
The LLM Wiki pattern, to compile and provide domain knowledge into a persistent artifact and serve it to LLMs via KV cache inference, promises context access at sub-second latency with zero retrieval failure. Realizing this requires solving the compilation gap: LLM compilation distilling raw documents into a wiki without catastrophically discarding critical facts. We characterize this gap across 17 RepLiQA domains (6,800 questions): we observe that full context KV cache inference outperforms RAG on curated knowledge (4.38 vs. 4.08 out of 5, 7.3 faster TTFT) but degrades below RAG at scale due to attention dilution, and blind compilation fails entirely (2.14 to 2.32 vs. 3.46, 53 to 60% catastrophic failure rate). To address the compilation gap, we propose WiCER (Wiki-memory Compile, Evaluate, Refine), an iterative algorithm inspired by counterexample-guided abstraction refinement (CEGAR) that closes this gap. WiCER evaluates compiled wikis against diagnostic probes, identifies dropped facts, and forces their preservation in subsequent compilations. One to two iterations recover 80% of lost quality (mean 3.24 vs. 3.47 for raw full-context across the 15 topics with baselines), reducing catastrophic failures by 55% relative. An ablation across all 17 topics confirms that targeted diagnosis (+0.95), not generic pinning (+0.16), drives the gains. All code and benchmarks are released for reproducible research.
Flawless - Durable Execution Engine
Flawless is an execution engine for durable computation. It will run your code until completion even in the presence of hardware or software failure.
Ante: A New Way to Blend Borrow Checking and Reference Counting
Ante has taken the first step towards something we all thought was impossible: blending reference counting and borrow checking without run-time crashes. 0
Revisiting Joel's Test - exe.dev blog
Joel Spolsky's twelve questions still hold, but agents demand nine more. Call it the Shelley test.
