How to Contribute Tests

Ori Pomerantz

You’ve written a useful test and now you want to contribute it to the repository. This tutorial teaches you how to do it.

Generalizing Tests

Many of our tests started from the need to test a single scenario, but we figured out related scenarios that are also worth testing. For example, this test started from a request to make a CREATE2 opcode fail at a specific stage.

However, there were two ways to generalize this:

While the state test transaction can only have one direct destination, we can provide whatever data we want, and that data can be used to calculate an address to call. Different addresses can contain contracts with different operations.

The easiest way to run multiple tests in a state test is to use different data values. You can use the :abi encoding to send multiple values. If you use uint, the first value will be available at $4 (LLL) or calldata(4) (Yul), the second value at $36 / calldata(0x24), etc.


The source/filler test file is written in either YML or JSON and located under the src directory. This is the type of file explained in the tutorials.

In addition to the source file, your pull request needs to include the generated/filled version(s) of the test file. This version includes additional information, such as merkle tree roots of the current state, the compiled bytecode, etc.


The directions below assume you are running retesteth through docker. See here if you are not familiar with using **retesteth** that way.

State Tests

State tests have their source at src/GeneralStateTestsFiller/<directory>/<test>Filler.<yml or json>. Every state test is supposed to have two filled versions:

  1. Filled state test, which is located in GeneralStateTests/<directory>/<test>.json. You use a command similar to this one to create this file:

    ./ -t $suite -- --testpath $dir --singletest $test --filltests
  2. Blockchain state test, which is located in BlockchainTests/GeneralStateTests/<directory>/<test>.json. You use a command similar to this one to create this file:

    ./ -t $suite -- --testpath $dir --singletest $test --fillchain

Blockchain Tests

State tests have their source at src/BlockchainTestsFiller/<directory>/<test>Filler.<yml or json>. These tests only have a single filled version, located in BlockchainTests/<directory>/<test>.json. You use a command similar to this one to create this file:

./ -t $suite -- --testpath $dir --singletest $test --filltests


At this point you should know enough to submit PRs with useful tests. Go write some and amaze us.