open-mock-file 1.0.1

# Open File Mock

## Description
This library contains object, which can be used during mocking files in tests. Features:

* You can register different actions (provide different objects for different paths) for different paths
* You can add content, which will be
* You can select behavior for paths, which is not registered. Supported behaviors:
* Raise FileNotFoundError exception (default behavior)
* Return original file from filesystem
* Return mock object

## Install
It can be installed with following command:

`pip install open-mock-file`


## Usage:

### Examples

Mock open first file with custom object, second one with string data and raise FileNotFoundError for not registered path:

```python
from unittest.mock import patch
from open_file_mock.mock_open import MockOpen


class FileObject:
def __init__(self, data):
self.data = data

def read(self, *args, **kwargs):
return self.data

def write(self, data, *args, **kwargs):
self.data = data

def __enter__(self):
return self

def __exit__(self, exc_type, exc_val, exc_tb):
pass


with patch('builtins.open', new_callable=MockOpen) as open_mock:
open_mock.register_object_for_path(path='/tmp/f1', obj=FileObject('Some data'))
open_mock.set_read_data_for(path='/tmp/f2', data='file2 data')
with open('/tmp/f1') as f1:
print(f1.read())
f1.write('Other data')
print(f1.read())
print('----------------------')

with open('/tmp/f2') as f2:
print(f2.read())
print('----------------------')

open('/etc/hostname')
```

**output:**
```
Some data
Other data
----------------------
file2 data
----------------------
Traceback (most recent call last):
...
FileNotFoundError: File /etc/hostname not found in mock function
```

Set default behavior (for not registered paths) to return original file:

```python
from unittest.mock import patch, MagicMock
from open_file_mock.mock_open import MockOpen, DEFAULTS_ORIGINAL

with patch('builtins.open', new_callable=MockOpen) as open_mock:
open_mock.default_behavior = DEFAULTS_ORIGINAL
open_mock.register_object_for_path(path='/tmp/f1', obj=MagicMock())
with open('/tmp/f1') as f1:
print(f1.read())
print('----------------------')

with open('/etc/hostname') as f2:
print(f2.read())
print('----------------------')

```

**output:**
```
<MagicMock name='mock.__enter__().read()' id='...'>
----------------------
myhostname

----------------------

```

Set default behavior to return new mock:

```python
from unittest.mock import patch
from open_file_mock.mock_open import MockOpen, DEFAULTS_MOCK

with patch('builtins.open', new_callable=MockOpen) as open_mock:
open_mock.default_behavior = DEFAULTS_MOCK
open_mock.set_read_data_for('/tmp/f1', 'QWERTY')
with open('/tmp/f1') as f1:
print(f1.read())
print('----------------------')

with open('/etc/hostname') as f2:
print(f2.read())
print('----------------------')

```

**output:**
```
QWERTY
----------------------
<MagicMock name='mock.__enter__().read()' id='...'>
```

Yoy can get registered object with *get_object_for_path* method:

```python
from unittest.mock import patch
from open_file_mock.mock_open import MockOpen


class FileObject:
def __init__(self, data):
self.data = data

def read(self, *args, **kwargs):
return self.data

def write(self, data, *args, **kwargs):
self.data = data

def __enter__(self):
return self

def __exit__(self, exc_type, exc_val, exc_tb):
pass


with patch('builtins.open', new_callable=MockOpen) as open_mock:
open_mock.register_object_for_path(path='/tmp/f1', obj=FileObject('Some data'))
open_mock.set_read_data_for(path='/tmp/f2', data='file2 data')
with open('/tmp/f1') as f1:
print(f1.read())
print('----------------------')

print(open_mock.get_object_for_path('/tmp/f1'))

```
**output:**
```
Some data
----------------------
<__main__.FileObject object at ...>
```

### Object methods:
* **register_object_for_path(path, obj)** - allow to register new object for provided path. Can be used once for particular path
* **update_object_for_path(path, obj)** - update registered path or create new mapping if not exists
* **unregister_path(path)** - remove path mapping
* **set_read_data_for(path, data)** - set data which will be returned of file read
* **get_object_for_path(path)** - returns object registered for path. If mapping not exists, raises KeyError