PRBTest is a modern collection of testing assertions and logging utilities for Solidity, and is meant to be a drop-in replacement for DSTest.
- Feature-packed: assertions for equalities, inequalities, approximate equalities, numerical comparisons, and more
- Type-rich: every assertion has overloads for
address,bytes,bytes32,int256,stringanduint256 - Versioned releases so that you don't accidentally pull the latest version and break your test suites
- Meant to be used with Foundry, but can also be used with Hardhat
- Complementary to Forge Std
- Designed for Solidity >=0.8.0
- Thoroughly tested
If you're starting a project from scratch, the easiest way to install PRBTest is to use my Foundry template, since it comes pre-configured with PRBTest.
This is the recommended approach.
Install PRBTest using your favorite package manager, e.g., with Bun:
bun add @prb/testThen, if you are using Foundry, you need to add this to your remappings.txt file:
@prb/test/=node_modules/@prb/test/src/
This installation method is not recommended, but it is available for those who prefer it.
First, install the submodule using Forge:
forge install --no-commit PaulRBerg/prb-test@release-v0Your .gitmodules file should now contain the following entry:
[submodule "lib/prb-test"]
branch = "release-v0"
path = "lib/prb-test"
url = "https://github.com/PaulRBerg/prb-test"Finally, add this to your remappings.txt file:
@prb/test/=lib/prb-test/
Once installed, all you need to do is import PRBTest and inherit from it in your test contract. PRBTest comes with a
pre-instantiated cheatcodes environment accessible via the vm property. It
also has support for logs.
// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.0;
import { PRBTest } from "@prb/test/PRBTest.sol";
contract MyTest is PRBTest {
function testExample() external {
vm.warp(block.timestamp + 100);
emit Log("Hello World");
assertTrue(true);
}
}All assertions have overloads with an additional err argument, so that you can pass custom error messages.
| Name | Argument Types |
|---|---|
assertTrue |
bool |
assertFalse |
bool |
assertEq |
address, bytes, bytes32, int256, string, uint256 and their array equivalents |
assertNotEq |
address, bytes, bytes32, int256, string, uint256 and their array equivalents |
assertAlmostEq |
int256 and uint256 |
assertGt |
int256 and uint256 |
assertGte |
int256 and uint256 |
assertLt |
int256 and uint256 |
assertLte |
int256 and uint256 |
assertContains |
address[], bytes32[], int256[], string[], and uint256[] |
PRBTest can be used alongside all testing utilities from forge-std, except for their Test contract.
Here's an example for how to use PRBTest with StdCheats and stdError:
// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.8.0;
import { PRBTest } from "@prb/test/PRBTest.sol";
import { StdCheats } from "forge-std/StdCheats.sol";
import { stdError } from "forge-std/Test.sol";
contract MyTest is PRBTest, StdCheats {
function testArithmeticOverflow() external {
uint256 a = type(uint256).max;
uint256 b = 1;
vm.expectRevert(stdError.arithmeticError);
a + b;
}
}DSTest is great. I have used it for a while, and I like it a lot. But, with time, I slowly came to realize that there's a lot of room for improvement.
DSTest is incomplete. Some commonly needed assertions, like equality assertions for arrays, assertEq(bool,bool) and
assertNotEq, are missing from DSTest. PRBTest fills these gaps, and then some.
Also, the DSTest testing assertions are not themselves tested. Whereas the PRBTest testing assertions are tested, and in fact they are quite thoroughly tested. All other things being equal, this should give you more confidence that your tests do what you intend them to do.
DSTest doesn't version its releases, which makes it difficult to future-proof consumer repos. It's quite easy to accidentally update your git submodules and thus break your test suites. For some users, this is a real pain.
PRBTest is versioned via tags and branches and all changes are tracked in a CHANGELOG file. I maintain redundant branches for each release because git submodules don't support tags.
I will strive to follow the semver versioning scheme, though I won't do this before the v1.0 release, and it might not always be feasible.
As one of the maintainers of DSTest said here, updating DSTest is painful to orchestrate. The reasons for this are twofold:
- Every DappTools project uses it as a git submodule.
- DSTest releases have not been versioned.
So any significant change in DSTest might wreak havoc downstream.
This issue has led to a "balkanization" of DSTest forks and extensions. See, for instance, Solmate's
DSTestPlus and Forge Std's Test. Also see the discussions in this
PR, in which the PR author ended up making the PR against forge-std
rather than ds-test because he feared that his PR won't be merged.
It is my firm conviction that Foundry is the future of Ethereum smart contract development. Solidity code is best tested in Solidity itself.
But, due to various historical reasons, the Ethereum ecosystem has for a long time relied upon JavaScript for testing smart contracts. Refactoring a code base from Hardhat or Truffle to Foundry takes time, and it may not always be possible to do it in one fell swoop. Thus, to ensure backward compatibility, PRBTest is available as a Node.js package in the npm package registry.
For more details about this, see this discussion here.
Feel free to dive in! Open an issue, start a discussion or submit a PR.
You will need the following software on your machine:
In addition, familiarity with Solidity is requisite.
Clone this repository including submodules:
$ git clone --recurse-submodules -j8 git@github.com:PaulRBerg/prb-test.gitThen, inside the project's directory, run this to install the Node.js dependencies:
$ bun installNow you can start making changes.
You will need the following VSCode extensions:
These contracts were inspired by or directly modified from the following sources:
This project is licensed under MIT.