{"id":425,"date":"2024-01-29T11:09:37","date_gmt":"2024-01-29T11:09:37","guid":{"rendered":"https:\/\/learnpython.elegantwallp.com\/?p=425"},"modified":"2024-01-29T11:09:40","modified_gmt":"2024-01-29T11:09:40","slug":"python-asserttrue","status":"publish","type":"post","link":"https:\/\/learnpython.elegantwallp.com\/2024\/01\/29\/python-asserttrue\/","title":{"rendered":"Python assertTrue()"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you\u2019ll learn how to use Python assertTrue()<\/code> to test if an expression is True and assertFalse()<\/code> method to test if an expression is False.<\/p>\n\n\n\n

Introduction to the Python assertTrue() method<\/h2>\n\n\n\n

The\u00a0assertTrue()<\/code>\u00a0is a method of the\u00a0TestCase<\/code>\u00a0class in the\u00a0unittest\u00a0module. The\u00a0assertTrue()<\/code>\u00a0method tests if an expression is\u00a0True<\/code>:<\/p>\n\n\n\n

assertTrue(expr, msg=None)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
If the expr<\/code> is True<\/code>, the test passes. Otherwise, the test fails.<\/p>\n\n\n\n
The msg<\/code> is optional. If you pass the msg<\/code> parameter, it\u2019ll be displayed when the test fails.<\/p>\n\n\n\n
The\u00a0assertTrue()<\/code>\u00a0method is equivalent to the following expression:<\/p>\n\n\n\n
bool(expr) is True<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
It is not equivalent to the following:<\/p>\n\n\n\n
expr is True<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In practice, you should use the assertTrue()<\/code> method to test the boolean of a variable. Also, you should not use the assertTrue()<\/code> method if more specific methods are available.<\/p>\n\n\n\n
For example, instead of using the\u00a0assertTrue()<\/code>\u00a0method for the following case:<\/p>\n\n\n\n
assertTrue(a == b)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
you should use the\u00a0assertEqual()<\/code>\u00a0method instead:<\/p>\n\n\n\n
assertEqual(a,b)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Because the assertEqual()<\/code> method provides a more clear error message in case the test fails.<\/p>\n\n\n\n
Python assertTrue() method example<\/h2>\n\n\n\n
The following example uses the\u00a0assertTrue()<\/code>\u00a0method to test if all characters in a string are digits:<\/p>\n\n\n\n
import unittest class TestBool(unittest.TestCase): def test_is_digit(self): str = '123' self.assertTrue(str.isdigit())<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Run the test:<\/p>\n\n\n\n
python -m unittest -v<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
test_is_digit (test_bool.TestBool) ... ok ---------------------------------------------------------------------- Ran 1 test in 0.000s OK<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Python assertFalse() method<\/h2>\n\n\n\n
The\u00a0assertFalse()<\/code>\u00a0method tests if an expression is\u00a0False<\/code>. For example:<\/p>\n\n\n\n
import unittest class TestBool(unittest.TestCase): def test_empty_string_is_digit(self): str = '' self.assertFalse(str.isdigit()) def test_alpha_is_digit(self): str = 'a00' self.assertFalse(str.isdigit())<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Run the test:<\/p>\n\n\n\n
python -m unittest -v<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
test_alpha_is_digit (test_bool.TestBool) ... ok test_empty_string_is_digit (test_bool.TestBool) ... ok test_is_digit (test_bool.TestBool) ... ok ---------------------------------------------------------------------- Ran 3 tests in 0.001s OK<\/code><\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
Summary: in this tutorial, you\u2019ll learn how to use Python assertTrue() to test if an expression is True and assertFalse() method to test if an expression is False. Introduction to the Python assertTrue() method The\u00a0assertTrue()\u00a0is a method of the\u00a0TestCase\u00a0class in the\u00a0unittest\u00a0module. The\u00a0assertTrue()\u00a0method tests if an expression is\u00a0True: If the expr is True, the test passes. Otherwise, the test fails. The msg is optional. If […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[43],"tags":[],"class_list":["post-425","post","type-post","status-publish","format-standard","hentry","category-3-python-unit-testing"],"_links":{"self":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/425","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/comments?post=425"}],"version-history":[{"count":1,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/425\/revisions"}],"predecessor-version":[{"id":426,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/425\/revisions\/426"}],"wp:attachment":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/media?parent=425"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/categories?post=425"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/tags?post=425"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}