---
anta_title: How to contribute to ANTA
---
<!--
  ~ Copyright (c) 2023-2026 Arista Networks, Inc.
  ~ Use of this source code is governed by the Apache License 2.0
  ~ that can be found in the LICENSE file.
  -->

Contribution model is based on a fork-model. Don't push to aristanetworks/anta directly. Always do a branch in your forked repository and create a PR.

To help development, open your PR as soon as possible even in draft mode. It helps other to know on what you are working on and avoid duplicate PRs.

## Create a development environment

Run the following commands to create an ANTA development environment:

```bash
# Clone repository
$ git clone https://github.com/aristanetworks/anta.git
$ cd anta

# Install ANTA in editable mode and its development tools
$ pip install -e . --group dev
# To also install the CLI
$ pip install -e .[cli] --group dev

# Verify installation
$ pip list -e
Package Version Editable project location
------- ------- -------------------------
anta    1.7.0   /mnt/lab/projects/anta
```

!!! info "Installation Note"
    1. If you are using a terminal such as zsh, ensure that commands involving shell expansions within editable installs (like specifying development dependencies) are enclosed in double quotes. For example: `pip install -e ."[cli]"`
    2. If you do not see any output when running the verification command (`pip list -e`), it is likely because the command needs to be executed from within the inner `anta` directory. Navigate to this directory and then verify the installation:

     ```
      $ cd anta/anta
      # Verify installation
      $ pip list -e
      Package Version Editable project location
      ------- ------- --------------------------
      anta    1.7.0   /mnt/lab/projects/anta
     ```

Then, [`tox`](https://tox.wiki/) is configured with few environments to run CI locally:

```bash
$ tox list -d
default environments:
clean  -> Erase previous coverage reports
lint   -> Check the code style
type   -> Check typing
py39   -> Run pytest with py39
py310  -> Run pytest with py310
py311  -> Run pytest with py311
py312  -> Run pytest with py312
report -> Generate coverage report
```

### Code linting

```bash
tox -e lint
[...]
lint: commands[0]> ruff check .
All checks passed!
lint: commands[1]> ruff format . --check
158 files already formatted
lint: commands[2]> pylint anta

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

lint: commands[3]> pylint tests

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

  lint: OK (22.69=setup[2.19]+cmd[0.02,0.02,9.71,10.75] seconds)
  congratulations :) (22.72 seconds)
```

### Code Typing

```bash
tox -e type

[...]
type: commands[0]> mypy --config-file=pyproject.toml anta
Success: no issues found in 68 source files
type: commands[1]> mypy --config-file=pyproject.toml tests
Success: no issues found in 82 source files
  type: OK (31.15=setup[14.62]+cmd[6.05,10.48] seconds)
  congratulations :) (31.18 seconds)
```

> NOTE: Typing is configured quite strictly, do not hesitate to reach out if you have any questions, struggles, nightmares.

## Unit tests with Pytest

To keep high quality code, we require to provide a **Pytest** for every tests implemented in ANTA.

All submodule should have its own pytest section under `tests/units/anta_tests/<submodule-name>.py`.

### How to write a unit test for an AntaTest subclass

The Python modules in the `tests.units.anta_tests` package define test parameters for AntaTest subclasses unit tests.
A generic test function is written for all unit tests of the `AntaTest` subclasses.
In order for your unit tests to be correctly collected, you need to import the generic test function even if not used in the Python module.

The `pytest_generate_tests` function definition in `conftest.py` is called during test collection.

The `pytest_generate_tests` function will parametrize the generic test function based on the `DATA` constant defined in modules in the `tests.units.anta_tests` package.

See <https://docs.pytest.org/en/7.3.x/how-to/parametrize.html#basic-pytest-generate-tests-example>

The `DATA` structure is a dictionary where:

- Each key is a tuple of size 2 containing:
  - An AntaTest subclass imported in the test module as first element - e.g. VerifyUptime.
  - A string used as name displayed by pytest as second element.
- Each value is an instance of AntaUnitTest, which is a Python TypedDict.

A `TypeAlias` called `AntaUnitTestData` has been created for convenience.

And AntaUnitTest have the following keys:

- `eos_data` (list[dict]): List of data mocking EOS returned data to be passed to the test.
- `inputs` (dict): Dictionary to instantiate the `test` inputs as defined in the class from `test`.
- `expected` (dict): Expected test result structure, a dictionary containing a key
    `result` containing one of the allowed status (`Literal[AntaTestStatus.SUCCESS, AntaTestStatus.FAILURE, AntaTestStatus.SKIPPED]`) and optionally a key `messages` which is a list(str) and each message is expected to be a substring of one of the actual messages in the TestResult object.

``` python
class AtomicResult(TypedDict):
    """Expected atomic result of a unit test of an AntaTest subclass."""

    description: str # The expected description of this atomic result.
    result: Literal[AntaTestStatus.SUCCESS, AntaTestStatus.FAILURE, AntaTestStatus.SKIPPED] # The expected status of this atomic result.
    messages: NotRequired[list[str]] # The expected messages of this atomic result. The strings can be a substrings of the actual messages.

class UnitTestResult(TypedDict):
    """Expected result of a unit test of an AntaTest subclass.

    For our AntaTest unit tests we expect only success, failure or skipped.
    Never unset nor error.
    """

    result: Literal[AntaTestStatus.SUCCESS, AntaTestStatus.FAILURE, AntaTestStatus.SKIPPED] # The expected status of this unit test.
    messages: NotRequired[list[str]] # The expected messages of the test. The strings can be a substrings of the actual messages.
    atomic_results: NotRequired[list[AtomicResult]] # The list of expected atomic results.

class AntaUnitTest(TypedDict):
    """The parameters required for a unit test of an AntaTest subclass."""

    inputs: NotRequired[dict[str, Any]] # The test inputs of this unit test.
    eos_data: list[dict[str, Any] | str] # List of command outputs used to mock EOS commands during this unit test.
    expected: UnitTestResult  # The expected result of this unit test.

AntaUnitTestData: TypeAlias = dict[tuple[type[AntaTest], str], AntaUnitTest]
```

Test example for `anta.tests.system.VerifyUptime` AntaTest.

``` python
# Import your AntaTest
from anta.tests.system import VerifyUptime

# Import the generic test function
from tests.units.anta_tests import test

# Define test parameters
DATA: AntaUnitTestData = {
  (VerifyUptime, "success"): {
    # JSON output of the 'show uptime' EOS command as defined in VerifyUptime.commands
    "eos_data": [{"upTime": 1186689.15, "loadAvg": [0.13, 0.12, 0.09], "users": 1, "currentTime": 1683186659.139859}],
    # Dictionary to instantiate VerifyUptime.Input
    "inputs": {"minimum": 666},
    # Expected test result
    "expected": {"result": AntaTestStatus.SUCCESS},
  },
  (VerifyUptime, "failure"): {
    "eos_data": [{"upTime": 665.15, "loadAvg": [0.13, 0.12, 0.09], "users": 1, "currentTime": 1683186659.139859}],
    "inputs": {"minimum": 666},
    # If the test returns messages, it needs to be expected otherwise test will fail.
    # The expected message can be a substring of the actual message.
    "expected": {"result": AntaTestStatus.FAILURE, "messages": ["Device uptime is 665.15 seconds"]},
  }
}
```

Test example for `anta.tests.connectivity.VerifyReachability` AntaTest that contains atomic results.

``` python
from anta.tests.connectivity import VerifyReachability
from tests.units.anta_tests import test

DATA: AntaUnitTestData = {
    (VerifyReachability, "failure-ip"): {
        "inputs": {"hosts": [{"destination": "10.0.0.11", "source": "10.0.0.5"}, {"destination": "10.0.0.2", "source": "10.0.0.5"}]},
        "eos_data": [
            {
                "messages": [
                    "ping: sendmsg: Network is unreachable\n                ping: sendmsg: Network is unreachable\n                "
                    "PING 10.0.0.11 (10.0.0.11) from 10.0.0.5 : 72(100) bytes of data.\n\n                --- 10.0.0.11 ping statistics ---\n"
                    "                2 packets transmitted, 0 received, 100% packet loss, time 10ms\n\n\n                "
                ]
            },
            {
                "messages": [
                    "PING 10.0.0.2 (10.0.0.2) from 10.0.0.5 : 72(100) bytes of data.\n                80 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=0.247 ms\n"
                    "                80 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=0.072 ms\n\n                --- 10.0.0.2 ping statistics ---\n                "
                    "2 packets transmitted, 2 received, 0% packet loss, time 0ms\n                rtt min/avg/max/mdev = 0.072/0.159/0.247/0.088 ms,"
                    " ipg/ewma 0.370/0.225 ms\n\n                "
                ]
            },
        ],
        "expected": {
            "result": AntaTestStatus.FAILURE,
            "messages": ["Unreachable Host 10.0.0.11 (src: 10.0.0.5, vrf: default, size: 100B, repeat: 2)"],
            # This test has implemented atomic results.
            # Expected atomic results must be specified or the test will fail. Order matters.
            # The atomic results must be defined in the same order.
            "atomic_results": [
                {
                    # Expected atomic result description
                    "description": "Destination 10.0.0.11 from 10.0.0.5 in VRF default",
                    # If the atomic result is tied to a subset of the test inputs, it needs to be added here otherwise the test will fail.
                    "inputs": {
                        "destination": "10.0.0.11",
                        "df_bit": False,
                        "repeat": 2,
                        "size": 100,
                        "source": "10.0.0.5",
                        "vrf": "default",
                    },
                    # Expected atomic result status
                    "result": AntaTestStatus.FAILURE,
                    # If the atomic result returns messages, it needs to be expected otherwise test will fail.
                    # The expected message can be a substring of the actual message.
                    # The messages must be defined in the same order.
                    "messages": ["Unreachable Destination 10.0.0.11 from 10.0.0.5 in VRF default"],
                },
                {
                    "description": "Host 10.0.0.2 in VRF default",
                    "inputs": {
                        "destination": "10.0.0.2",
                        "df_bit": False,
                        "repeat": 2,
                        "size": 100,
                        "source": "10.0.0.5",
                        "vrf": "default",
                    },
                    "messages": [],
                    "result": AntaTestStatus.SUCCESS,
                },
            ],
        },
    }
}
```

## Git Pre-commit hook

```bash
pip install pre-commit
pre-commit install
```

When running a commit or a pre-commit check:

``` bash
❯ pre-commit
trim trailing whitespace.................................................Passed
fix end of files.........................................................Passed
check for added large files..............................................Passed
check for merge conflicts................................................Passed
Check and insert license on Python files.................................Passed
Check and insert license on Markdown files...............................Passed
Run Ruff linter..........................................................Passed
Run Ruff formatter.......................................................Passed
Check code style with pylint.............................................Passed
Checks for common misspellings in text files.............................Passed
Check typing with mypy...................................................Passed
Check Markdown files style...............................................Passed
```

## Configure MYPYPATH

In some cases, mypy can complain about not having `MYPYPATH` configured in your shell. It is especially the case when you update both an anta test and its unit test. So you can configure this environment variable with:

```bash
# Option 1: use local folder
export MYPYPATH=.

# Option 2: use absolute path
export MYPYPATH=/path/to/your/local/anta/repository
```

## Documentation

[`mkdocs`](https://www.mkdocs.org/) is used to generate the documentation. A PR should always update the documentation to avoid documentation debt.

### Install documentation requirements

Run pip to install the documentation requirements from the root of the repo:

```bash
pip install -e . --group doc
```

### Testing documentation

You can then check locally the documentation using the following command from the root of the repo:

```bash
mkdocs serve
```

By default, `mkdocs` listens to <http://127.0.0.1:8000/>, if you need to expose the documentation to another IP or port (for instance all IPs on port 8080), use the following command:

```bash
mkdocs serve --dev-addr=0.0.0.0:8080
```

### Build class diagram

To build class diagram to use in API documentation, you can use `pyreverse` part of `pylint` with [`graphviz`](https://graphviz.org/) installed for jpeg generation.

```bash
pyreverse anta --colorized -a1 -s1 -o jpeg -m true -k --output-directory docs/imgs/uml/ -c <FQDN anta class>
```

Image will be generated under `docs/imgs/uml/` and can be inserted in your documentation.

### Checking links

Writing documentation is crucial but managing links can be cumbersome. To be sure there is no dead links, you can use [`muffet`](https://github.com/raviqqe/muffet) with the following command:

```bash
muffet -c 2 --color=always http://127.0.0.1:8000 -e fonts.gstatic.com -b 8192
```

## Continuous Integration

GitHub actions is used to test git pushes and pull requests. The workflows are defined in this [directory](https://github.com/aristanetworks/anta/tree/main/.github/workflows). The results can be viewed [here](https://github.com/aristanetworks/anta/actions).