mixer¶

Gerador de objetos

Problema¶

Escrita de testes geralmente demanda instanciar e popular vários objetos e suas dependências até que possam ser persistidos no banco de dados;

Motivação¶

Facilitar a escrita de testes;
- Que dependem de registros no banco de dados ou;
- Instâncias em memória;
Foco nas propriedades relevantes para o seu teste.
Sem fixtures;
Sem factories;

Setup¶

pip install mixer

fake-factory¶

fake-factory é o motor do Mixer e possui providers para gerar dados aleatórios

In [2]:

from faker import Factory

faker = Factory.create()
for _ in range(5):
    print(faker.name())

Imelda Lang
Sable Bogisich
Terrell Lind II
Ms. Helena Wolf
Redmond Stiedemann

In [3]:

from faker import Factory

faker = Factory.create('pt_BR')
print(faker.name())

Bianca Costela

In [4]:

print(faker.address())

Núcleo Castro, 388
Conjunto Jatoba
63875355 Dias / AC

In [5]:

print(faker.phone_number())

81 6126-4767

Instanciar objetos¶

from mixer.main import Mixer

class SomeScheme:
    score = int
    name = str

mixer = Mixer()
instance = mixer.blend(SomeScheme)
print instance.name  # Some like: 'Mike Douglass'

mixer = Mixer(fake=False)
instance = mixer.blend(SomeScheme)
print instance.name  # Some like: 'AKJfdjh3'

In [6]:

# Dica: Usar models do Django em um IPython Notebook
import os
import django
os.environ['DJANGO_SETTINGS_MODULE'] = 'conf.settings'
django.setup()

courses/models.py¶

class Student(models.Model):
    name = models.CharField(max_length=30)
    def __str__(self): return self.name


class Course(models.Model):
    name = models.CharField(max_length=30)
    def __str__(self): return self.name


class Score(models.Model):
    points = models.IntegerField(max_length=4)
    course = models.ForeignKey('Course')
    student = models.ForeignKey('Student')

    def __str__(self):
        return "{s} has {p} points.".format(s=self.student, p=self.points)

In [17]:

# Obter um objeto
from mixer.backend.django import mixer

score = mixer.blend('courses.Score')

In [18]:

print "points: ", score.points
print "course: ", score.course
print "student: ", score.student

points:  3706
course:  Mr. Guss Blick PhD
student:  Macedo

In [23]:

# Iniciar variáveis relevantes ao teste
score = mixer.blend('courses.Score', score=11, student__name='Macedo')
print "points: ", score.points
print "course: ", score.course
print "student: ", score.student

points:  9295
course:  Anabelle Hudson
student:  Macedo

In [31]:

# Suporta generators
seq_name = mixer.sequence('Macedo {0}')
seq_points = (p for p in [30, 13, 55])

for counter in range(3):
    print mixer.blend('courses.Score', points=seq_points, student__name=seq_name)

Macedo 0 has 30
Macedo 1 has 13
Macedo 2 has 55

In [32]:

# Ciclos para facilitar a geração de vários objetos
students = mixer.cycle(5).blend('courses.Student')
print students

[<Student: Mr. Dennie Reichel III>, <Student: Teagan Hartmann>, <Student: Janis Ondricka>, <Student: Myrtle Wolff>, <Student: Carmen O'Connell>]

É isso!¶

Fernando Macedo
fgmacedo@gmail.com
Trabalho na labCorp (estamos contratando!)
@fgmacedo
github.com/fgmacedo