Add cookie overriding/adding (#26)

* Add cookie overriding/adding

* Black

* Clearout migrations

* Ensure cookie overriding only works in debug mode

* Add test for when cookies are not present

* Edit text

Author: adinhodovic

django_google_optimize/admin.py

@@ -1,6 +1,10 @@
 from django.contrib import admin
 
-from .models import ExperimentVariant, GoogleExperiment
+from .models import ExperimentCookie, ExperimentVariant, GoogleExperiment
+
+
+class ExperimentCookieInline(admin.StackedInline):
+    model = ExperimentCookie
 
 
 class ExperimentVariantInline(admin.StackedInline):
@@ -13,6 +17,4 @@ class GoogleExperimentAdmin(admin.ModelAdmin):
         "experiment_id",
         "experiment_alias",
     )
-    inlines = [
-        ExperimentVariantInline,
-    ]
+    inlines = [ExperimentVariantInline, ExperimentCookieInline]

django_google_optimize/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 3.0.2 on 2020-01-28 16:33
+# Generated by Django 3.0.2 on 2020-01-29 07:56
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -30,6 +30,15 @@ class Migration(migrations.Migration):
                 ('experiment', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='experiment_variant', to='django_google_optimize.GoogleExperiment')),
             ],
         ),
+        migrations.CreateModel(
+            name='ExperimentCookie',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('active_variant_index', models.IntegerField(help_text='Overrides or adds the cookie and sets the active variant for this experiment\nNOTE: ONLY WORKS IN DEBUG MODE')),
+                ('active', models.BooleanField()),
+                ('experiment', models.OneToOneField(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='experiment_cookie', to='django_google_optimize.GoogleExperiment')),
+            ],
+        ),
         migrations.AddConstraint(
             model_name='experimentvariant',
             constraint=models.UniqueConstraint(fields=('alias', 'experiment'), name='Can not have the same alias within an experiment_variant'),

django_google_optimize/models.py

@@ -31,3 +31,18 @@ class Meta:
                 name="Can not have the same index within an experiment_variant",
             ),
         ]
+
+
+class ExperimentCookie(models.Model):
+    active_variant_index = models.IntegerField(
+        # pylint: disable=line-too-long
+        help_text="Overrides or adds the cookie and sets the active variant for this experiment\nNOTE: ONLY WORKS IN DEBUG MODE"
+    )
+    active = models.BooleanField()
+    experiment = models.OneToOneField(
+        GoogleExperiment,
+        null=True,
+        blank=True,
+        on_delete=models.CASCADE,
+        related_name="experiment_cookie",
+    )

django_google_optimize/utils.py

@@ -1,6 +1,8 @@
 import logging
 
-from .models import GoogleExperiment
+from django.conf import settings
+
+from .models import ExperimentCookie, GoogleExperiment
 
 logger = logging.getLogger()
 
@@ -63,19 +65,25 @@ def get_experiments_variants(request):
     return active_experiments
 
 
-def _parse_experiments(request):
+def _parse_experiments(request,):
     ga_exp = request.COOKIES.get("_gaexp")
-    if not ga_exp:
-        return None
 
     experiment_variations = {}
-
-    parts = ga_exp.split(".")
-    experiments_part = ".".join(parts[2:])
-    experiments = experiments_part.split("!")
-    for experiment_str in experiments:
-        experiment_parts = experiment_str.split(".")
-        experiment_id = experiment_parts[0]
-        variation_id = int(experiment_parts[2])
-        experiment_variations[experiment_id] = variation_id
-    return experiment_variations
+    if ga_exp:
+        parts = ga_exp.split(".")
+        experiments_part = ".".join(parts[2:])
+        experiments = experiments_part.split("!")
+        for experiment_str in experiments:
+            experiment_parts = experiment_str.split(".")
+            experiment_id = experiment_parts[0]
+            variation_id = int(experiment_parts[2])
+            experiment_variations[experiment_id] = variation_id
+    if settings.DEBUG:
+        cookies = ExperimentCookie.objects.filter(active=True)
+        for cookie in cookies:
+            experiment_variations[
+                cookie.experiment.experiment_id
+            ] = cookie.active_variant_index
+    if experiment_variations:
+        return experiment_variations
+    return None

tests/settings.py

@@ -1,7 +1,5 @@
 from os import path
 
-DEBUG = True
-
 SECRET_KEY = "very-secret"
 
 DATABASES = {"default": {"ENGINE": "django.db.backends.sqlite3", "NAME": "db.sqlite3"}}

tests/test_helpers.py

@@ -1,6 +1,10 @@
 import factory
 
-from django_google_optimize.models import ExperimentVariant, GoogleExperiment
+from django_google_optimize.models import (
+    ExperimentCookie,
+    ExperimentVariant,
+    GoogleExperiment,
+)
 
 
 # pylint: disable=too-few-public-methods
@@ -21,3 +25,12 @@ class Meta:
     alias = factory.Faker("city")
     index = factory.Faker("pyint")
     experiment = factory.SubFactory(GoogleExperimentFactory)
+
+
+class ExperimentCookieFactory(factory.django.DjangoModelFactory):
+    class Meta:
+        model = ExperimentCookie
+
+    active_variant_index = factory.Faker("pyint")
+    active = True
+    experiment = factory.SubFactory(GoogleExperimentFactory)

tests/test_utils.py

@@ -3,7 +3,11 @@
 import pytest
 from django.http import HttpRequest
 
-from .test_helpers import ExperimentVariantFactory, GoogleExperimentFactory
+from .test_helpers import (
+    ExperimentCookieFactory,
+    ExperimentVariantFactory,
+    GoogleExperimentFactory,
+)
 
 from django_google_optimize.utils import _parse_experiments, get_experiments_variants
 
@@ -153,3 +157,42 @@ def test_filters_active_experiments():
     request.COOKIES["_gaexp"] = f"GAX1.2.{exp.experiment_id}.18147.{variant.index}"
     values = get_experiments_variants(request)
     assert values == {exp.experiment_alias: variant.alias}
+
+
+@pytest.mark.django_db
+def test_cookie_override(settings):
+    settings.DEBUG = True
+    exp = GoogleExperimentFactory()
+    variant = ExperimentVariantFactory(index=1, experiment=exp)
+    ExperimentCookieFactory(active_variant_index=variant.index, experiment=exp)
+
+    request = HttpRequest()
+    request.COOKIES["_gaexp"] = f"GAX1.2.{exp.experiment_id}.18147.5"
+
+    values = get_experiments_variants(request)
+    assert values == {exp.experiment_alias: variant.alias}
+
+
+@pytest.mark.django_db
+def test_cookie_add_new(settings):
+    settings.DEBUG = True
+    exp = GoogleExperimentFactory()
+    variant = ExperimentVariantFactory(index=1, experiment=exp)
+    ExperimentCookieFactory(active_variant_index=variant.index, experiment=exp)
+
+    request = HttpRequest()
+    values = get_experiments_variants(request)
+    assert values == {exp.experiment_alias: variant.alias}
+
+
+@pytest.mark.django_db
+def test_cookie_override_only_debug():
+    exp = GoogleExperimentFactory()
+    variant = ExperimentVariantFactory(index=1, experiment=exp)
+    ExperimentCookieFactory(active_variant_index=5, experiment=exp)
+
+    request = HttpRequest()
+    request.COOKIES["_gaexp"] = f"GAX1.2.{exp.experiment_id}.18147.1"
+
+    values = get_experiments_variants(request)
+    assert values == {exp.experiment_alias: variant.alias}