Close T200

T198

- Not found
- Bad request

+ Improve coverage

Close T195

Close T199

Close T201

+ update default base_url

+ Improve docstrings and warnings

This permits to make sure the call takes place as expected.

Beware though that does not permit to check the values have not been
hard-coded...

Improve test readability and maintenance.

The setup needs some clarification though

<~=~> dependency injection

Still, we must enforce this before flask

Sample client:
```python
import requests
r = requests.post(
      'http://localhost:6543/api/1/uploadnsearch/',
      files={'file': open(filepath, 'rb')})
```

Sample output:

```ipython3
In [125]: r.content
Out[125]: b'{\n  "found": true,\n  "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709"\n}'
```