Exercise: Refactoring - Extract Both CSV Formats Into Module

Requirement

Create a module userdb_csv.py to be imported from whatever program. That module will contain

• The function you created in Exercise: Refactoring - Extract CSV Reading Into Function (csv.reader) Exercise: Refactoring - Extract CSV Reading Into Function (csv.dictreader); that is the function which reads our user database from a CSV file which has a header line.

• Modify both programs (read-userdb.py and read-userdb-header.py) to import the module, and to use the functions from there.

Test Code

The following test (see pytest Introduction, By Example for how to use it) can better express the requirement,

code/tests/test_read_csv.py

# -*- encoding: utf-8 -*-

import userdb_csv

import pytest


def test_noheader(tmpdir):
    with open(tmpdir/'noheader.csv', 'w', encoding='cp1252') as f:
        f.writelines([
            '1;"Jörg;DI";Faschingbauer;19.6.1966\n',
            '2;Caro;Faschingbauer;25.4.1997\n',
            '3;Johanna;Faschingbauer;11.6.1995\n',
            '4;Philipp;Lichtenberger;6.4.1986\n',
            '5;Elizabeth II;Queen;1.1.1900\n',
        ])
            
    users = list(userdb_csv.read_csv_noheader(tmpdir/'noheader.csv'))

    assert users[0]['id'] == 1
    assert users[0]['firstname'] == 'Jörg;DI'
    assert users[0]['lastname'] == 'Faschingbauer'
    assert users[0]['birth'] == '19.6.1966'

    assert users[1]['id'] == 2
    assert users[1]['firstname'] == 'Caro'
    assert users[1]['lastname'] == 'Faschingbauer'
    assert users[1]['birth'] == '25.4.1997'

    assert users[2]['id'] == 3
    assert users[2]['firstname'] == 'Johanna'
    assert users[2]['lastname'] == 'Faschingbauer'
    assert users[2]['birth'] == '11.6.1995'

    assert users[3]['id'] == 4
    assert users[3]['firstname'] == 'Philipp'
    assert users[3]['lastname'] == 'Lichtenberger'
    assert users[3]['birth'] == '6.4.1986'

    assert users[4]['id'] == 5
    assert users[4]['firstname'] == 'Elizabeth II'
    assert users[4]['lastname'] == 'Queen'
    assert users[4]['birth'] == '1.1.1900'

def test_header(tmpdir):
    with open(tmpdir/'header.csv', 'w', encoding='cp1252') as f:
        f.writelines([
            'ID;First name;Last name;Date of Birth\n',
            '1;"Jörg;DI";Faschingbauer;19.6.1966\n',
            '2;Caro;Faschingbauer;25.4.1997\n',
            '3;Johanna;Faschingbauer;11.6.1995\n',
            '4;Philipp;Lichtenberger;6.4.1986\n',
            '5;Elizabeth II;Queen;1.1.1900\n',
        ])
            
    users = list(userdb_csv.read_csv_header(tmpdir/'header.csv'))

    assert users[0]['id'] == 1
    assert users[0]['firstname'] == 'Jörg;DI'
    assert users[0]['lastname'] == 'Faschingbauer'
    assert users[0]['birth'] == '19.6.1966'

    assert users[1]['id'] == 2
    assert users[1]['firstname'] == 'Caro'
    assert users[1]['lastname'] == 'Faschingbauer'
    assert users[1]['birth'] == '25.4.1997'

    assert users[2]['id'] == 3
    assert users[2]['firstname'] == 'Johanna'
    assert users[2]['lastname'] == 'Faschingbauer'
    assert users[2]['birth'] == '11.6.1995'

    assert users[3]['id'] == 4
    assert users[3]['firstname'] == 'Philipp'
    assert users[3]['lastname'] == 'Lichtenberger'
    assert users[3]['birth'] == '6.4.1986'

    assert users[4]['id'] == 5
    assert users[4]['firstname'] == 'Elizabeth II'
    assert users[4]['lastname'] == 'Queen'
    assert users[4]['birth'] == '1.1.1900'