Mocking Db calls

This is a short test to show

• simple Db access
  • create
  • insert
  • query

But I wanted to also develop some tests, especially Database Mocks.

DB

This code creates a sqlite3, which is placed in the modules installed folder.

The database is called People.db, and it has 1 table called Phone, which has 2 fields (Name, Dial).

Real Query

This is what the real query looks like.

def test_real_query():
   """"
   Do the test Using
   """
   p = People()
   assert p is not None
   assert len(p.query()) == 3

Mock way 1

This is done with

from People import People
#Package.Class.method
@patch('People.People.query')
def test_fake_query(mock_function):
    """"
    Do the test using fake data.
    """
    mock_function.return_value = [('Superman', ' 1'), ('Avengers', '2')]
    p = People()
    assert p is not None

    pprint(p.query())
    print("Hi can be seen with -s flag")
    assert len(p.query()) == 2
    names=[rec[0] for rec in p.query()]
    assert "Superman" in names
    assert "Avengers" in names

Mock way 2

A slight difference.

#Class.method
@patch.object(People,"query",
              return_value=[('Superman', ' 1'), ('Avengers', '2')])
def test_fake_query2(mock_function):
    """"
    Do the test using fake data.
    Slightly different call than the previous version.
    But with the same result
    """
    #mock_function.return_value = [('Superman', ' 1'), ('Avengers', '2')]
    p = People()
    assert p is not None
    pprint(p.query())
    print("Hi can be seen with -s flag")
    assert len(p.query()) == 2
    names=[rec[0] for rec in p.query()]
    assert "Superman" in names
    assert "Avengers" in names
    assert "tim" not in names

I hope this assists you in developing your own tests/mocks.

Why Mock ?

Sometimes testing is slow, need specific values (difficult in real time systems), requires complex infrastructure to be on-line.

Is mocking easy ?

Yes, and no....

It rather depends how your code has been written, if you are using a non-class delivery mechanism, then Mocks are quite straightforward.

Testing

In the tests/ folder you should see some example tests.

I have "Real" ones that hit the database (sqlite3), and fake/mocked ones, one's that give the data that I want to persist in the tests.

I would suggest that in real-life these could be implemented as two sets of tests.

• Laptop/Test/Quick. I.e. Mocked
• Real. In the Beta Env.