TestingMutation testing
Mutation rules
Reference of all available mutation rules in Acton
Acton ships 49 built-in mutation rules, categorized by their type. Use rule IDs with acton test --mutation-disable-rules <RULE> or [test.mutation].disable-rules inside Acton.toml.
Critical rules
These rules affect control flow, assertions, storage persistence, and contract upgrade or external-message semantics. Mutations in this category that survive are often indicators of missing tests for security-critical behavior.
| Rule | Description | Explanation |
|---|---|---|
remove_assert | Remove assert statements | This assertion is not covered by tests. This could lead to security vulnerabilities if the condition is not enforced. |
remove_throw | Remove throw keyword | This exception path is not covered by tests. Missing error handling might leave the contract in an inconsistent state. |
remove_storage_save_call | Remove save() method calls | This storage save operation is not covered by tests. Without this call, data changes won't be persisted to storage. |
remove_set_data_call | Remove contract.setData() calls | This storage write is not covered by tests. Without this call, updated state will not be persisted. |
remove_accept_external_message | Remove acceptExternalMessage() calls | This external accept path is not covered by tests. Without this call, external message handling semantics may break. |
remove_commit_contract_data_and_actions | Remove commitContractDataAndActions() calls | This commit path is not covered by tests. Without this call, state persistence and replay-protection semantics may break. |
remove_set_code_postponed | Remove contract.setCodePostponed() calls | This upgrade path is not covered by tests. Without this call, code-upgrade semantics may break. |
replace_if_condition_with_true | Replace if condition with true | The conditional logic is not fully covered. |
replace_if_condition_with_false | Replace if condition with false | The conditional logic is not fully covered. |
replace_while_condition_with_false | Replace while condition with false | The loop execution path is not fully covered. |
remove_logical_not | Remove logical NOT (!) | The logical negation is not fully covered. |
Arithmetic rules
These rules mutate arithmetic operations to ensure calculations are verified by tests.
| Rule | Description |
|---|---|
replace_plus_with_minus | Replace + with - |
replace_minus_with_plus | Replace - with + |
replace_multiply_with_divide | Replace * with / |
replace_divide_with_multiply | Replace / with * |
replace_multiply_assign_with_divide_assign | Replace *= with /= |
replace_divide_assign_with_multiply_assign | Replace /= with *= |
replace_multiply_assign_with_modulo_assign | Replace *= with %= |
replace_modulo_assign_with_multiply_assign | Replace %= with *= |
replace_plus_assign_with_minus_assign | Replace += with -= |
replace_minus_assign_with_plus_assign | Replace -= with += |
remove_unary_minus | Remove unary minus (-) |
Comparison rules
These rules mutate comparison operators to check if boundary conditions are tested.
| Rule | Description |
|---|---|
replace_equal_with_not_equal | Replace == with != |
replace_not_equal_with_equal | Replace != with == |
replace_less_than_with_less_or_equal | Replace < with <= |
replace_greater_than_with_greater_or_equal | Replace > with >= |
replace_less_or_equal_with_less_than | Replace <= with < |
replace_greater_or_equal_with_greater_than | Replace >= with > |
Boolean and logical rules
These rules invert boolean values and logical operators.
| Rule | Description |
|---|---|
replace_true_with_false | Replace true with false |
replace_false_with_true | Replace false with true |
replace_logical_and_with_logical_or | Replace && with || |
replace_logical_or_with_logical_and | Replace || with && |
Bitwise rules
These rules mutate bitwise operators, compound bitwise assignments, and shifts.
| Rule | Description |
|---|---|
replace_bitwise_and_with_bitwise_or | Replace & with | |
replace_bitwise_or_with_bitwise_and | Replace | with & |
replace_bitwise_and_with_bitwise_xor | Replace & with ^ |
replace_bitwise_or_with_bitwise_xor | Replace | with ^ |
replace_bitwise_xor_with_bitwise_and | Replace ^ with & |
replace_bitwise_xor_with_bitwise_or | Replace ^ with | |
replace_bitwise_and_assign_with_bitwise_or_assign | Replace &= with |= |
replace_bitwise_and_assign_with_bitwise_xor_assign | Replace &= with ^= |
replace_bitwise_or_assign_with_bitwise_and_assign | Replace |= with &= |
replace_bitwise_or_assign_with_bitwise_xor_assign | Replace |= with ^= |
replace_bitwise_xor_assign_with_bitwise_and_assign | Replace ^= with &= |
replace_bitwise_xor_assign_with_bitwise_or_assign | Replace ^= with |= |
replace_left_shift_assign_with_right_shift_assign | Replace <<= with >>= |
replace_right_shift_assign_with_left_shift_assign | Replace >>= with <<= |
replace_left_shift_with_right_shift | Replace << with >> |
replace_right_shift_with_left_shift | Replace >> with << |
remove_bitwise_not | Remove bitwise NOT (~) |
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