# python

## pandas

[Link](https://gist.github.com/bitliner/217f4162ad4160cd7c969ea73fdc591c)

<hr>

## pytest

### mock

Assume `pip install pytest-mock` or `poetry add pytest-mock`

```python
def test_me(mocker):
    mocker.patch(
        "module1.module2.module3.function", return_value=value
    )
```

Be careful with `from module1.module2 import fn` statement, see [link](http://www.gregreda.com/2021/06/28/mocking-imported-module-function-python/) 

[pytest-mock documentation](https://pytest-mock.readthedocs.io/en/latest/)

<hr>

### snapshot testing

```bash
pip install pytest-snapshot
```

```python
def test_me(snapshot):
    snapshot.assert_match(output)
```

If pandas dataframe, then use `output.to_csv()` since `assert_match()` accepts strings, not bytes

```bash
pytest --snapshot-update
```

## simple server

`python -m SimpleHTTPServer <port_number> -d <dir>`

## unused dependencies

[Tool to identify unused deps](https://fpgmaas.github.io/deptry/)

## poetry

**add dev deps**

`poetry add --group dev deptry`

**set in-project env** (folder .venv will be within the project)

`poetry config virtualenvs.in-project true`