YJDH-808 | Backend: Add & populate Company.created_at & modified_at fields

backend/kesaseteli/companies/migrations/0009_company_created_at_company_modified_at.py

@@ -0,0 +1,28 @@
+# Generated by Django 5.1.15 on 2026-02-05 11:09
+
+import django.utils.timezone
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("companies", "0008_make_company_business_id_unique"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="company",
+            name="created_at",
+            field=models.DateTimeField(
+                auto_now_add=True,
+                default=django.utils.timezone.now,
+                verbose_name="time created",
+            ),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name="company",
+            name="modified_at",
+            field=models.DateTimeField(auto_now=True, verbose_name="time modified"),
+        ),
+    ]

backend/kesaseteli/companies/migrations/0010_populate_company_timestamps.py

@@ -0,0 +1,29 @@
+from django.db import migrations
+
+from companies.migrations.helpers.company_timestamps import populate_company_timestamps
+
+
+def populate_company_timestamps_with_apps(apps, schema_editor):
+    """
+    Populate Company.created_at and Company.modified_at fields based on the
+    earliest EmployerApplication.created_at that references each Company.
+
+    Companies without any EmployerApplication references are left unchanged,
+    because there is no data to determine appropriate timestamps for them.
+    """
+    company_model = apps.get_model("companies", "Company")
+    populate_company_timestamps(company_model)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("companies", "0009_company_created_at_company_modified_at"),
+        ("applications", "0045_employersummervoucher_job_type_and_more"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            populate_company_timestamps_with_apps,
+            migrations.RunPython.noop,
+        ),
+    ]

backend/kesaseteli/companies/migrations/helpers/company_timestamps.py

@@ -0,0 +1,41 @@
+import logging
+
+from django.db.models import Min
+
+LOGGER = logging.getLogger(__name__)
+
+
+def populate_company_timestamps(company_model):
+    """
+    Populate Company.created_at and Company.modified_at fields based on the
+    earliest EmployerApplication.created_at that references each Company.
+
+    Companies without any EmployerApplication references are left unchanged,
+    because there is no data to determine appropriate timestamps for them.
+    """
+    total_count = company_model.objects.count()
+
+    companies_with_min_created_at = (
+        company_model.objects.filter(employer_applications__isnull=False)
+        .annotate(min_application_created_at=Min("employer_applications__created_at"))
+        .only("id")
+    )
+
+    companies_to_update = []
+
+    for company in companies_with_min_created_at:
+        company.created_at = company.min_application_created_at
+        company.modified_at = company.min_application_created_at
+        companies_to_update.append(company)
+
+    updated_count = company_model.objects.bulk_update(
+        companies_to_update,
+        fields=["created_at", "modified_at"],
+        batch_size=500,  # To limit a single batch's SQL UPDATE clause size
+    )
+
+    LOGGER.info(f"Handled {total_count} companies:")
+    LOGGER.info(
+        f"- Set timestamps using related employer applications: {updated_count}"
+    )
+    LOGGER.info(f"- Did nothing for unused companies: {total_count - updated_count}")

backend/kesaseteli/companies/models.py

@@ -2,10 +2,10 @@
 from django.utils.translation import gettext_lazy as _
 
 from applications.enums import OrganizationType
-from shared.models.abstract_models import UUIDModel
+from shared.models.abstract_models import TimeStampedModel, UUIDModel
 
 
-class Company(UUIDModel):
+class Company(UUIDModel, TimeStampedModel):
     name = models.CharField(max_length=256, verbose_name=_("name"))
     business_id = models.CharField(
         max_length=64, unique=True, verbose_name=_("business id")

backend/kesaseteli/companies/tests/test_populate_company_timestamps.py

@@ -0,0 +1,190 @@
+"""
+Tests for populate_company_timestamps migration function
+used in migration "0010_populate_company_timestamps".
+
+These tests use the current data models. These tests CAN BE REMOVED
+later IF the data MODELS CHANGE radically, rather than trying to
+maintain them indefinitely.
+"""
+
+from datetime import datetime, timedelta
+
+import pytest
+from django.utils import timezone
+from freezegun import freeze_time
+
+from common.tests.factories import CompanyFactory, EmployerApplicationFactory
+from companies.migrations.helpers.company_timestamps import populate_company_timestamps
+from companies.models import Company
+
+
+@pytest.mark.django_db
+def test_populate_single_company_with_single_application():
+    """
+    Test that populate_company_timestamps correctly sets timestamps for a
+    company with a single employer application.
+    """
+    with freeze_time("2025-01-01 12:00"):
+        company = CompanyFactory()
+
+    # Create an employer application with an earlier timestamp
+    with freeze_time("2024-01-15 10:30"):
+        employer_app = EmployerApplicationFactory(company=company)
+
+    expected_timestamp = employer_app.created_at
+    assert company.created_at != expected_timestamp
+    assert company.modified_at != expected_timestamp
+
+    # Run the migration function
+    populate_company_timestamps(Company)
+
+    # After migration, company should have the employer application's created_at
+    company.refresh_from_db()
+    assert company.created_at == expected_timestamp
+    assert company.modified_at == expected_timestamp
+
+
+@pytest.mark.django_db
+def test_populate_company_with_multiple_applications():
+    """
+    Test that populate_company_timestamps uses the earliest employer
+    application's created_at timestamp when multiple applications exist.
+    """
+    company = CompanyFactory()
+
+    # Create three employer applications with different timestamps
+    timestamps = [
+        timezone.make_aware(datetime(2024, 3, 20, 14, 0)),
+        timezone.make_aware(datetime(2024, 1, 10, 9, 0)),  # Earliest
+        timezone.make_aware(datetime(2024, 6, 15, 16, 30)),
+    ]
+
+    for timestamp in timestamps:
+        employer_app = EmployerApplicationFactory(company=company)
+        employer_app.created_at = timestamp
+        employer_app.save()
+
+    # Run the migration function
+    populate_company_timestamps(Company)
+
+    # Company should have the earliest timestamp
+    company.refresh_from_db()
+    earliest_timestamp = min(timestamps)
+    assert company.created_at == earliest_timestamp
+    assert company.modified_at == earliest_timestamp
+
+
+@pytest.mark.django_db
+def test_company_without_applications_unchanged():
+    """
+    Test that companies without any employer applications remain unchanged.
+    """
+    company = CompanyFactory()
+    assert company.employer_applications.count() == 0
+    original_created_at = company.created_at
+    original_modified_at = company.modified_at
+
+    # Run the migration function
+    populate_company_timestamps(Company)
+
+    # Company timestamps should remain unchanged
+    company.refresh_from_db()
+    assert company.created_at == original_created_at
+    assert company.modified_at == original_modified_at
+
+
+@pytest.mark.django_db
+def test_multiple_companies_with_different_scenarios():
+    """
+    Test populate_company_timestamps with multiple companies:
+    some with applications, one without.
+    """
+    base_time = timezone.make_aware(datetime(2024, 1, 1, 0, 0))
+
+    # 1st company with multiple applications - should use earliest
+    company_multi_1 = CompanyFactory()
+    timestamps_multi_1 = [
+        base_time + timedelta(days=d) for d in [10, 5, 15]
+    ]  # 5 is earliest
+    for timestamp in timestamps_multi_1:
+        app = EmployerApplicationFactory(company=company_multi_1)
+        app.created_at = timestamp
+        app.save()
+
+    # 2nd company with multiple applications - should use earliest
+    company_multi_2 = CompanyFactory()
+    timestamps_multi_2 = [
+        base_time + timedelta(days=d) for d in [-5, -10, 3]
+    ]  # -10 is earliest
+    for timestamp in timestamps_multi_2:
+        app = EmployerApplicationFactory(company=company_multi_2)
+        app.created_at = timestamp
+        app.save()
+
+    # Company with single application
+    company_single = CompanyFactory()
+    timestamp_single = base_time + timedelta(days=20)
+    app = EmployerApplicationFactory(company=company_single)
+    app.created_at = timestamp_single
+    app.save()
+
+    # Company without applications - should remain unchanged
+    company_none = CompanyFactory()
+    original_created = company_none.created_at
+
+    populate_company_timestamps(Company)
+
+    # Sanity check that the earliest timestamps for the multi-application companies are different
+    assert min(timestamps_multi_1) != min(timestamps_multi_2)
+
+    company_multi_1.refresh_from_db()
+    assert company_multi_1.created_at == min(timestamps_multi_1)
+    assert company_multi_1.modified_at == min(timestamps_multi_1)
+
+    company_multi_2.refresh_from_db()
+    assert company_multi_2.created_at == min(timestamps_multi_2)
+    assert company_multi_2.modified_at == min(timestamps_multi_2)
+
+    company_single.refresh_from_db()
+    assert company_single.created_at == timestamp_single
+    assert company_single.modified_at == timestamp_single
+
+    company_none.refresh_from_db()
+    assert company_none.created_at == original_created
+
+
+@pytest.mark.django_db
+def test_populate_company_timestamps_query_count(django_assert_max_num_queries):
+    """
+    Test that populate_company_timestamps uses at most 3 queries.
+
+    NOTE:
+        With larger datasets, the chunk/bulk sizes in the migration
+        function will make the actual query count higher!
+    """
+    for i, company in enumerate(CompanyFactory.create_batch(size=15)):
+        if i < 10:  # First 10 companies get 3 applications each, last 5 do not
+            EmployerApplicationFactory.create_batch(company=company, size=3)
+
+    with django_assert_max_num_queries(3):
+        populate_company_timestamps(Company)
+
+
+@pytest.mark.django_db
+def test_populate_company_timestamps_logger_output(caplog):
+    """
+    Test that populate_company_timestamps logs the expected summary output.
+    """
+    # Create 3 companies: 2 with applications, 1 without
+    EmployerApplicationFactory(company=CompanyFactory())
+    EmployerApplicationFactory(company=CompanyFactory())
+    CompanyFactory()
+
+    with caplog.at_level("INFO"):
+        populate_company_timestamps(Company)
+
+        assert "Handled 3 companies:\n" in caplog.text
+        assert (
+            "- Set timestamps using related employer applications: 2\n" in caplog.text
+        )
+        assert "- Did nothing for unused companies: 1\n" in caplog.text