move-unit-testing

move-unit-testing

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Overview

AI agents consistently use outdated or suboptimal patterns when writing Move unit tests. This skill covers the correct testing conventions from the official Sui Move code quality checklist and testing documentation.

All patterns sourced from https://move-book.com/guides/code-quality-checklist and https://move-book.com/testing/

No test_ Prefix in Test Modules

Test functions inside _tests modules should NOT be prefixed with test_. The module name already indicates these are tests. Use descriptive names that read as statements.

// WRONG — redundant prefix
module my_package::my_module_tests;

#[test]
fun test_create_pool() { /* ... */ }

#[test]
fun test_swap_fails_on_zero() { /* ... */ }

// CORRECT — descriptive statement names
module my_package::my_module_tests;

#[test]
fun create_pool_with_initial_liquidity() { /* ... */ }

#[test]
fun swap_aborts_on_zero_input() { /* ... */ }

Use assert_eq! Instead of assert! for Comparisons

assert_eq! displays both values on failure, making debugging much easier. Never use assert!(x == y) or assert!(x == y, 0) for equality checks.

// WRONG — no diagnostic info on failure
assert!(result == 100);
assert!(result == expected_value, 0);

// CORRECT — shows both values on failure
use std::unit_test::assert_eq;

assert_eq!(result, 100);
assert_eq!(result, expected_value);

Use plain assert! only for boolean conditions where there's nothing to compare:

// assert! is fine for boolean checks
assert!(is_valid);
assert!(vec.length() > 0);

No Abort Codes in Test assert!

Do not pass numeric abort codes to assert! in tests. They can accidentally match application error codes and confuse debugging.

// WRONG — numeric code may collide with app errors
assert!(is_success, 0);
assert!(balance > 0, 1);

// CORRECT — no abort code
assert!(is_success);
assert!(balance > 0);