fun/web/documentation/writing-tests/writing-tests.md

layout	published	noToc	noComments	noDate	title	subtitle	description	permalink	lang	tags
page	true	false	false	false	Fun - Writing Tests	How to author new tests for Fun and opcode components.	How to author new tests for Fun and opcode components.	/documentation/writing-tests/	en	author components new opcode tests writing

How to author tests for Fun and its opcode implementations.

Test kinds

• VM/opcode tests: exercise bytecode operations and VM behavior (target: test_opcodes).
• Language/runtime tests: exercise user-visible features and stdlib behavior (target: fun_test).

See documentation/testing.md for how to build and run these targets with CTest.

Adding new tests

The exact layout may evolve; generally:

• Add new test sources alongside existing ones used by fun_test.
• For opcode-focused tests, add cases where test_opcodes discovers them.

Aim for:

• Small, isolated test cases with clear assertions
• One behavior per test; descriptive names
• Minimal fixtures and setup

Guidelines

• Prefer black-box testing via public APIs.
• When adding features, include both positive and negative cases.
• Keep tests deterministic; avoid non-deterministic timers or random sources unless seeded.