¿Qué sucede cuando ejecuta la prueba manage.py?

La traducción del artículo fue preparada especialmente para los estudiantes del curso Python Web-Developer .

Ejecuta las pruebas con un comando manage.py test, pero ¿sabe qué está pasando debajo del capó? ¿Cómo funciona el corredor de pruebas y cómo coloca los puntos, E y F en la pantalla?

A medida que aprenda cómo funciona Django, descubrirá muchos casos de uso, como cambiar cookies, configurar encabezados globales y registrar solicitudes. Asimismo, una vez que comprenda cómo funcionan las pruebas, puede personalizar los procesos para, por ejemplo, cargar pruebas en un orden diferente, configurar parámetros de prueba sin un archivo separado o bloquear solicitudes HTTP salientes.

En este artículo, analizaremos la personalización vital de la salida de sus pruebas, así como también cambiaremos el estilo de visualización de los resultados de las pruebas de puntos y letras a emoji.

Sin embargo, antes de escribir el código, hagamos una reconstrucción del proceso de prueba.

Salida de prueba

Echemos un vistazo a los resultados de la prueba. Tomemos un proyecto con una prueba vacía como base:

from django.test import TestCase


class ExampleTests(TestCase):
    def test_one(self):
        pass

Cuando ejecutamos nuestras pruebas, obtenemos un resultado familiar:

$ python manage.py test
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
.
----------------------------------------------------------------------
Ran 1 test in 0.001s

OK
Destroying test database for alias 'default'...

, , , -v 3:

$ python manage.py test -v 3
Creating test database for alias 'default' ('file:memorydb_default?mode=memory&cache=shared')...
Operations to perform:
  Synchronize unmigrated apps: core
  Apply all migrations: (none)
Synchronizing apps without migrations:
  Creating tables...
    Running deferred SQL...
Running migrations:
  No migrations to apply.
System check identified no issues (0 silenced).
test_one (example.core.tests.test_example.ExampleTests) ... ok

----------------------------------------------------------------------
Ran 1 test in 0.004s

OK
Destroying test database for alias 'default' ('file:memorydb_default?mode=memory&cache=shared')...

, ! .

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, – 100 . handle() TestRunner. :

def handle(self, *test_labels, **options):
    TestRunner = get_runner(settings, options['testrunner'])
    ...
    test_runner = TestRunner(**options)
    ...
    failures = test_runner.run_tests(test_labels)
    ...

.

TestRunner? Django, . , , Django – django.test.runner.DiscoverRunner. .

DiscoverRunner

DiscoverRunner – . , , - .

- :

class DiscoverRunner:
    """A Django test runner that uses unittest2 test discovery."""

    test_suite = unittest.TestSuite
    parallel_test_suite = ParallelTestSuite
    test_runner = unittest.TextTestRunner
    test_loader = unittest.defaultTestLoader

(, )

, . , – unittest.

, test_runner, , «test runner» — DiscoverRunner Django TextTestRunner unittest. DiscoverRunner , TextTestRunner, . , Django DiscoverRunner -, , TestCoordinator, . 

DiscoverRunner runtests(). , run_tests() :

def run_tests(self, test_labels, extra_tests=None, **kwargs):
    self.setup_test_environment()
    suite = self.build_suite(test_labels, extra_tests)
    databases = self.get_databases(suite)
    old_config = self.setup_databases(aliases=databases)
    self.run_checks(databases)
    result = self.run_suite(suite)
    self.teardown_databases(old_config)
    self.teardown_test_environment()
    return self.suite_result(suite, result)

. , :

• setup_databases() . , , get_databases(), SimpleTestCases , Django . migrate.

• run_checks() .

• run_suite() , .

• teardown_databases() .

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• setup_test_environment() teardown_test_environment() , .

• suite_result() .

, . Django. unittest - build_suite() run_suite().

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buildsuite()

buildsuite() «suite». , , :

def build_suite(self, test_labels=None, extra_tests=None, **kwargs):
    suite = self.test_suite()
    test_labels = test_labels or ['.']

    for label in test_labels:
        tests = self.test_loader.loadTestsFromName(label)
        suite.addTests(tests)

    if self.parallel > 1:
        suite = self.parallel_test_suite(suite, self.parallel, self.failfast)

    return suite

, , , DiscoverRunner:

• test_suite - unittest, .

• parallel_test_suite - , Django.

• test_loader – unittest, .

runsuite()

DiscoverRunner, – run_suite(). , , :

def run_suite(self, suite, **kwargs):
    kwargs = self.get_test_runner_kwargs()
    runner = self.test_runner(**kwargs)
    return runner.run(suite)

– test runner . unittest, . unittest.TextTestRunner - test runner , , , XML- CI-. 

, TextTestRunner.

TextTestRunner

unittest - . :

class TextTestRunner(object):
    """A test runner class that displays results in textual form.
    It prints out the names of tests as they are run, errors as they
    occur, and a summary of the results at the end of the test run.
    """
    resultclass = TextTestResult

    def __init__(self, ..., resultclass=None, ...):

( )

DiscoverRunner, . TextTestResult . DiscoverRunner, resultclass, TextTestRunner._init_().

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Django :

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• DiscoverRunner, TESTRUNNER .

– , DiscoverRunner. DiscoverRunner unittest , , .

Test Runner

, . DiscoverRunner runtests(), super():

# example/test.py
from django.test.runner import DiscoverRunner


class SuperFastTestRunner(DiscoverRunner):
    def run_tests(self, *args, **kwargs):
        print("All tests passed! A+")
        failures = 0
        return failures

:

TEST_RUNNER = "example.test.SuperFastTestRunner"

manage.py test, !

$ python manage.py test
All tests passed! A+

, !

, !

, TextTestResult unittest . DiscoverRunner, resultclass TextTestRunner.

Django resultclass, , --debug-sql option, .

 DiscoverRunner.run_suite() TextTestRunner DiscoverRunner.get_test_runner_kwargs():

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def get_test_runner_kwargs(self):
    return {
        'failfast': self.failfast,
        'resultclass': self.get_resultclass(),
        'verbosity': self.verbosity,
        'buffer': self.buffer,
    }

get_resultclass(), , (--debug-sql --pdb):

def get_resultclass(self):
    if self.debug_sql:
        return DebugSQLTextTestResult
    elif self.pdb:
        return PDBDebugResult

, None, TextTestResult resultclass. None TextTestResult:

class EmojiTestRunner(DiscoverRunner):
    def get_resultclass(self):
        klass = super().get_resultclass()
        if klass is None:
            return EmojiTestResult
        return klass

EmojiTestResult TextTestResult . , :

class EmojiTestResult(unittest.TextTestResult):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # If the "dots" style was going to be used, show emoji instead
        self.emojis = self.dots
        self.dots = False

    def addSuccess(self, test):
        super().addSuccess(test)
        if self.emojis:
            self.stream.write('✅')
            self.stream.flush()

    def addError(self, test, err):
        super().addError(test, err)
        if self.emojis:
            self.stream.write('?')
            self.stream.flush()

    def addFailure(self, test, err):
        super().addFailure(test, err)
        if self.emojis:
            self.stream.write('❌')
            self.stream.flush()

    def addSkip(self, test, reason):
        super().addSkip(test, reason)
        if self.emojis:
            self.stream.write("⏭")
            self.stream.flush()

    def addExpectedFailure(self, test, err):
        super().addExpectedFailure(test, err)
        if self.emojis:
            self.stream.write("❎")
            self.stream.flush()

    def addUnexpectedSuccess(self, test):
        super().addUnexpectedSuccess(test)
        if self.emojis:
            self.stream.write("✳️")
            self.stream.flush()

    def printErrors(self):
        if self.emojis:
            self.stream.writeln()
        super().printErrors()

TEST_RUNNER EmojiTestRunner, :

$ python manage.py test
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
?❎❌⏭✅✅✅✳️

...

----------------------------------------------------------------------
Ran 8 tests in 0.003s

FAILED (failures=1, errors=1, skipped=1, expected failures=1, unexpected successes=1)
Destroying test database for alias 'default'...

!

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