Learn what a test is and how to run the first one of your own with the pytest library! You will get used to the pytest testing framework and the command-line interface. You will also learn how to process specific contexts, like "failed tests" and "skipping the test" with pytest markers.

Introduction to Testing in Python

The first test suite

pytest.raises

Invoking pytest from CLI

Run the test!

Run with the keyword

Applying test markers

Markers use cases

Failed tests with xfail

Conditional skipping

Creating Tests with pytest

Learn what a fixture is and how to simplify your code by using it in tests. You will get familiar with the fixture @pytest.fixture decorator and the fixture tools. You will analyze your code to see the "fixture part" in it. Finally, learn how to use teardowns to prevent software failures.

Introduction to fixtures

Getting familiar with fixtures

Data preparation

Run with a fixture

Chain Fixtures Requests

Chain this out

List with a custom length

Fixtures autouse

autouse statements

Auto add numbers

Fixtures Teardowns

Data with teardown

Read data with teardown

Pytest Fixtures

Learn what the basic testing types are and their features. Learn about test cases and how they help to implement tests. You will get more skilled with creating test functions and running pytest from CLI in IDE exercises. Finally, you will be able to differentiate the different testing types and create tests for each of them.

Unit testing with pytest

Unit testing terms

Cover more test cases

Factorial of number

Run factorial

Feature testing with pytest

Feature or unit testing

Aggregate with sum

Integration testing with pytest

Integration test or not

Read the file

Performance testing with pytest

What is performance testing?

Finding an element

Speed of loops

Basic Testing Types

In this final chapter, you will meet the unittest framework. First, you will learn basic assertion methods, then its CLI interface, and how to use fixtures. Finally, you will put everything together in the practical examples of data pipelines.

Incontriamo unittest

Fattoriale con unittest

È primo oppure no

Interfaccia CLI

import unittest

def func_factorial(number):
    if number < 0:
        raise ValueError('Factorial is not defined for negative values')
    factorial = 1
    while number > 1:
        factorial = factorial * number
        number = number - 1
    return factorial

class TestFactorial(unittest.TestCase):
    def test_positives(self):
        self.assertEqual(func_factorial(5), 120)

    def test_zero(self):
        self.assertEqual(func_factorial(0), 1)

    def test_negatives(self):
        with self.assertRaises(ValueError):
            func_factorial(-1)


Esegui factorial con unittest

import unittest

def err_func_factorial(number):
    if number < 0:
        raise ValueError('Factorial is not defined for negative values')
    factorial = 1
    while number > 2:
        factorial = factorial * number
        number = number - 1
    return factorial

class TestFactorial(unittest.TestCase):
    def test_err_func_1(self):
        self.assertEqual(err_func_factorial(3), 6)
    def test_err_func_2(self):
        self.assertEqual(err_func_factorial(4), 24)


import unittest

def err_func_factorial(number):
    if number < 0:
        raise ValueError('Factorial is not defined for negative values')
    factorial = 1
    while number > 1:
        factorial = factorial * number
        number = number - 1
    return factorial

class TestFactorial(unittest.TestCase):
    def test_err_func_1(self):
        self.assertEqual(err_func_factorial(3), 6)
    def test_err_func_2(self):
        self.assertEqual(err_func_factorial(4), 24)


Fattoriale errato

- Run this command to run the testing script with the verbose flag:
  python3 -m unittest -v err_factorial_unittest.py
  
- Run this command to run the testing script with the fail fast flag:
  python3 -m unittest -f err_factorial_unittest.py
  
- Run this command to run the testing script with the keyword flag:
  python3 -m unittest -k "err_func_1" err_factorial_unittest.py


Opzioni di unittest

Fixture in unittest

import unittest

class TestWord(unittest.TestCase):
    # Fixture setup method
    def setUp(self):
        # Initialize the word banana here
        self.word = ____

    # Test method
    def test_the_word(self):
        # Add the tests here
        ____
        ____
        ____
    
    # Fixture teardown method
    def tearDown(self):
        # Delete the word variable here
        ____


import unittest

class TestWord(unittest.TestCase):
    # Fixture setup method
    def setUp(self):
        # Initialize the word banana here
        self.word = 'banana'

    # Test method
    def test_the_word(self):
        # Add the tests here
        self.assertIn('b', self.word)
        self.assertNotIn('B', self.word)
        self.assertNotIn('y', self.word)
    
    # Fixture teardown method
    def tearDown(self):
        # Delete the word variable here
        del self.word


Testa la variabile stringa

import unittest

def check_palindrome(string):
    reversed_string = string[::-1]
    return string == reversed_string

def create_data():
    return ['level', 'step', 'peep', 'toot']

class TestPalindrome(unittest.TestCase):
    def setUp(self):
        # Initialize data here
        ____
    
    def test_func(self):
        expected_result = [True, False, True, True]
        data_checked = list(map(check_palindrome, self.data))
        # Verify the checked data here
        ____

    def tearDown(self):
        # Clear the data here
        ____


import unittest

def check_palindrome(string):
    reversed_string = string[::-1]
    return string == reversed_string

def create_data():
    return ['level', 'step', 'peep', 'toot']

class TestPalindrome(unittest.TestCase):
    def setUp(self):
        # Initialize data here
        self.data = create_data()
    
    def test_func(self):
        expected_result = [True, False, True, True]
        data_checked = list(map(check_palindrome, self.data))
        # Verify the checked data here
        self.assertEqual(data_checked, expected_result)

    def tearDown(self):
        # Clear the data here
        self.data.clear()


Verifica palindromo

Esempi pratici

import pytest
import pandas as pd

DF_PATH = "/usr/local/share/salaries.csv"
@pytest.fixture
def read_df():
    return pd.read_csv(DF_PATH)

def get_grouped(df):
    return df.groupby('work_year').agg({'salary': 'describe'})['salary']

def test_read_df(read_df):
    # Check the type of the dataframe
    ____
    # Check that read_df contains rows
    ____

def test_grouped(read_df):
    df = read_df
    salary_by_year = get_grouped(df)
    # Check the nulls here
    ____


import pytest
import pandas as pd

DF_PATH = "/usr/local/share/salaries.csv"
@pytest.fixture
def read_df():
    return pd.read_csv(DF_PATH)

def get_grouped(df):
    return df.groupby('work_year').agg({'salary': 'describe'})['salary']

def test_read_df(read_df):
    # Check the type of the dataframe
    assert isinstance(read_df, pd.DataFrame)
    # Check that df contains rows
    assert read_df.shape[0] > 0

def test_grouped(read_df):
    df = read_df
    salary_by_year = get_grouped(df)
    # Check the nulls here
    assert salary_by_year.isna().sum().sum() == 0


Test di integrazione e unitari

import pytest
import pandas as pd

DF_PATH = "/usr/local/share/salaries.csv"
@pytest.fixture
def read_df():
    return pd.read_csv(DF_PATH)

def get_grouped(df):
    return df.groupby('work_year').agg({'salary': 'describe'})['salary']

def test_feature_2022(read_df):
    salary_by_year = get_grouped(read_df)
    salary_2022 = salary_by_year.loc[2022, '50%']
    # Check the median type here
    ____
    # Check the median is greater than zero
    ____

# Use benchmark here
def test_reading_speed(____):
    ____


import pytest
import pandas as pd

DF_PATH = "/usr/local/share/salaries.csv"
@pytest.fixture
def read_df():
    return pd.read_csv(DF_PATH)

def get_grouped(df):
    return df.groupby('work_year').agg({'salary': 'describe'})['salary']

def test_feature_2022(read_df):
    salary_by_year = get_grouped(read_df)
    salary_2022 = salary_by_year.loc[2022, '50%']
    # Check the median type here
    assert isinstance(salary_2022, float)
    # Check the median is greater than zero
    assert 0 < salary_2022

# Use benchmark here
def test_reading_speed(benchmark):
    benchmark(pd.read_csv, DF_PATH)


Test di funzionalità e prestazioni

import unittest
import pandas as pd
DF_PATH = 'https://assets.datacamp.com/production/repositories/6253/datasets/f015ac99df614ada3ef5e011c168054ca369d23b/energy_truncated.csv'

def get_data():
    return pd.read_csv(DF_PATH)

def min_country(df):
    return df['VALUE'].idxmin()

class TestDF(unittest.TestCase):
    def setUp(self):
        self.df = get_data()
        self.df.drop('previousYearToDate', axis=1, inplace=True)
        self.df = self.df.groupby('COUNTRY')\
            .agg({'VALUE': 'sum'})

    def test_NAs(self):
        # Check the number of nulls
        ____

    def test_argmax(self):
        # Check that min_country returns a string
        ____

    def tearDown(self):
        self.df.drop(self.df.index, inplace=True)


import unittest
import pandas as pd
DF_PATH = 'https://assets.datacamp.com/production/repositories/6253/datasets/f015ac99df614ada3ef5e011c168054ca369d23b/energy_truncated.csv'

def get_data():
    return pd.read_csv(DF_PATH)

def min_country(df):
    return df['VALUE'].idxmin()

class TestDF(unittest.TestCase):
    def setUp(self):
        self.df = get_data()
        self.df.drop('previousYearToDate', axis=1, inplace=True)
        self.df = self.df.groupby('COUNTRY')\
            .agg({'VALUE': 'sum'})

    def test_NAs(self):
        # Check the number of nulls
        self.assertEqual(self.df.isna().sum().sum(), 0)

    def test_argmax(self):
        # Check that min_country returns a string
        self.assertIsInstance(min_country(self.df), str)

    def tearDown(self):
        self.df.drop(self.df.index, inplace=True)


Pipeline energetica

Congratulazioni!

Writing tests with unittest

DS_salaries

Energy

Games

Molte persone scrivono codice. Alcune riescono a farlo funzionare e a renderlo redditizio. Ma a volte, anche il programmatore più brillante commette un errore che può costare milioni di dollari. Come ridurre la possibilità di finire in un simile fiasco? Come assicurarti di creare un programma che faccia esattamente ciò che vuoi? La risposta è semplice: scrivi dei test!

In questo percorso imparerai le basi della creazione di test in Python. Vedrai quattro tipi di metodi di testing del software. Scriverai test tuoi per verificare che un programma o una pipeline di dati funzioni come previsto prima di andare in produzione. Che si tratti di un valore null inaspettato, di un refuso nel tuo insieme di dati o di segni scambiati in un’equazione, con i test puoi — e riuscirai a — intercettare questi casi.

Al termine del corso, conoscerai i diversi tipi di metodi di testing e saprai scegliere quelli più adatti al contesto. Sarai anche in grado di progettare questi test e implementarli in Python usando le librerie pytest e unittest.

<h2>Perché i test?</h2>Un sacco di gente scrive codice. Alcuni riescono a farlo funzionare e a renderlo redditizio. Ma a volte, anche i programmatori più bravi e in gamba fanno errori che possono costare un sacco di soldi. Come ridurre la possibilità di finire in un pasticcio del genere? Come fai a essere sicuro di creare un programma che faccia proprio quello che vuoi? La risposta è super semplice: fai dei test!<br><br><h2>Nozioni di base sui test in Python</h2>Durante questo percorso imparerai le basi della creazione di test in Python. Incontrerai quattro tipi di metodi di test del software. Creerai i tuoi test per controllare se il programma o una pipeline di dati funzionano come dovrebbero prima di passare alla produzione. Che si tratti di un valore nullo inaspettato, di un errore di battitura nel tuo set di dati o di segni confusi nell'equazione. Puoi farlo, e riuscirai a individuare questi casi con i test.<br><br><h2>Test con pytest e unittest</h2>Dopo aver finito il corso, conoscerai i diversi tipi di metodi di test e potrai scegliere quelli più adatti a un contesto specifico. Potrai anche progettare questi test e metterli in pratica in Python usando le librerie `pytest` e `unittest`.

Writing Functions in Python

Software Engineering Principles in Python

Padroneggia i test Python: scopri metodi, crea verifiche e assicura codice senza errori con pytest e unittest.

Introduzione al Testing in Python

Diventa un esperto dei test Python: Impara i metodi, crea controlli e assicurati che il codice sia privo di errori con pytest e unittest.

Fattoriale errato

Introduzione al Testing in Python

Esercizio pratico interattivo