Unitary

Unitary Testing¶

Unitary tests rely solely on pytest fixtures to test the Vyper source code.

They do not fork the state of the blockchain but only test on an empty chain through titanoboa.

Folder Structure¶

Each contract should have its own folder inside the unitary folder. The naming convention for the folder is to use the snake_case version of the contract file name without the .vy extension.

i.e. contracts/Twocrypto.vy should have its own folder inside tests/unitary/twocrypto/.

For each contract method, there should be a corresponding test file: - The test file should be named test_<method_name>.py for external methods. - The test file should be named test_internal_<method_name>.py for internal methods.

For the sake of the example, let's say we have the following contracts to test, layed out as specified in the contracts folder structure:

contracts/
├── Twocrypto.vy
└── TwocryptoFactory.vy

Let's say that the Twocrypto contract has the following methods:

@external
def swap(amount: uint256):
    assert amount > 0
    self.calc_amount()

@external
def add_liquidity():
    pass

@internal
def calc_amount():
    pass

and the TwocryptoFactory contract has the following methods:

@external
def create_pool():
    pass

The test folder should be structured as follows:

tests/
├── unitary/
│   ├── twocrypto/
│   │   ├── test_swap.py
│   │   ├── test_add_liquidity.py
│   │   └── test_internal_calc_amount.py
│   ├── twocrypto_factory/
│   │   └── test_create_pool.py
│   └── conftest.py

Test File Structure¶

Since we have one test file per contract method, we can have multiple test functions per file.

What we usually want to test is: - The happy path (default_behavior), i.e. the normal flow of the function, covering all the possible branches. - All the edge cases, explicitely checking that we hit the correct revert messages.

Let's continue with our example and write the test file for the swap method.

unitary/conftest.py and fixtures¶

The conftest.py file is used to define the fixtures that are used in the test files.

This file should contain only fixtures that are specific to unitary tests (i.e. fixtures that are not used in fork tests). If the fixture is required by both unitary and fork tests it should be definited in tests/conftest.py.

Let's add the fixtures that we need for our tests.

from pytest import fixture

from tests.utils.

@fixture
def twocrypto_factory():