def test_success_register_new_user(self):
    values = {
        'password': 'rgwr34fwr',
        'username': 'test_username',
        'email': 'test@mail.test'
    }
    form = LoginForm(values)
    self.assertTrue(form.is_valid())

class SignUpForm(forms.Form):
username = forms.CharField(max_length=20)
email = forms.EmailField()
password = forms.CharField(widget=forms.PasswordInput)

def clean_email(self):
    user = get_user_model()
    self.cleaned_data['email'] = self.cleaned_data['email'].lower()
    try:
        user.objects.get(email=self.cleaned_data['email'])
        raise forms.ValidationError('User with this email already exists')
    except user.DoesNotExist:
        return self.cleaned_data['email']

def clean_username(self):
    user = get_user_model()
    self.cleaned_data['username'] = self.cleaned_data['username'].lower()
    try:
        user.objects.get(username=self.cleaned_data['username'])
        raise forms.ValidationError('User with this username already exists')
    except user.DoesNotExist:
        return self.cleaned_data['username']

def save(self):
    return get_user_model().objects.create_user(username=self.cleaned_data['username'],
                                                email=self.cleaned_data['email'],
                                                password=self.cleaned_data['password'])