eth-mutants is a mutation testing tool for Solidity contracts.
It about performing changes to your code (like replacing a < for a <=) and
running your tests. If they pass we say that the mutation lived/survived, which
means that you werent checking the condition and you should ensure there is a
test case covering it.
It's a great companion to existing test coverage tools, ensuring that you are not only running every line, but actually asserting logic about the control flow around them.
For more information, check out the Wikipedia page on mutation testing.
npm install eth-mutants
The `preflight` command will show the number of possible mutations found
and print some compact diffs for each mutation. Use this to understand
how long it may take to visit all mutations and please report any invalid
ones.
The test command will start applying mutations and running your tests to
check if they pass. It will report the result of each mutation.
eth-mutants test
This tools makes some important assumptions about your workspace, which should hold true for most Truffle-based projects, but I plan on adding options to override them soon:
- Your contract files are in the
contracts/directory - You run your tests with
npm testwhich returns a non-zero error code in case of failure.
The only mutation implemented at the moment is called boundary-condition
and replaces < and > for <= and >= and vice-versa. Contributions for
mutators are especially welcomed.
- PIT is a mutation testing tool for Java with a long track record.
- mutmut is a mutation testing tool for Python.
Federico Bond
MIT