Add _company_cost_velocity helper + 3 tests

Computes company-wide avg daily and monthly labour cost for the
executive report's hero KPI band (cards 3 and 4). Denominator is
working days (distinct work-log dates), not calendar days — true
cost-of-a-productive-day metric per design section 2.

Monthly = daily * 30.44 (the 365.25/12 month-length approximation,
which keeps annualised totals correct on average).

Tests cover: empty DB returns zero, known values with assertAlmostEqual
for the 30.44 multiplication, and that multiple workers on one date
count as 1 working day (not N).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

core/tests.py

@@ -476,3 +476,61 @@ class SupervisorPickerQuerysetTests(TestCase):
             username='an_admin', password='pass', is_staff=True
         )
         self.assertIn(admin, _supervisor_user_queryset())
+
+
+# =============================================================================
+# === TESTS FOR EXECUTIVE REPORT v2 ===
+# Covers the new helpers introduced in the report rebuild (Apr 2026):
+# _company_cost_velocity, _current_outstanding_in_scope, _team_project_activity,
+# and the multi-filter extension of _build_report_context.
+# =============================================================================
+
+
+class CompanyCostVelocityTests(TestCase):
+    """Company-wide avg daily and monthly labour cost (hero KPI card 3 & 4)."""
+
+    def test_empty_db_returns_zero(self):
+        from core.views import _company_cost_velocity
+        result = _company_cost_velocity()
+        self.assertEqual(result['avg_daily'], Decimal('0.00'))
+        self.assertEqual(result['avg_monthly'], Decimal('0.00'))
+        self.assertEqual(result['working_days'], 0)
+
+    def test_known_values(self):
+        from core.views import _company_cost_velocity
+        # Setup: 2 workers (daily_rate = 4000/20 = R 200 each), each works 5 distinct dates.
+        # Lifetime cost = 2 workers * 5 days * R 200 = R 2000. Working days = 5.
+        # Avg daily = 2000 / 5 = R 400.
+        # Avg monthly = 400 * 30.44 = R 12,176.
+        admin = User.objects.create_user(username='admin-cv', is_staff=True)
+        project = Project.objects.create(name='P')
+        w1 = Worker.objects.create(name='W1', id_number='W1', monthly_salary=Decimal('4000'))
+        w2 = Worker.objects.create(name='W2', id_number='W2', monthly_salary=Decimal('4000'))
+        for d in range(1, 6):  # 5 distinct dates
+            log = WorkLog.objects.create(
+                date=datetime.date(2026, 3, d),
+                project=project, supervisor=admin,
+            )
+            log.workers.add(w1, w2)
+
+        result = _company_cost_velocity()
+        self.assertEqual(result['working_days'], 5)
+        self.assertEqual(result['avg_daily'], Decimal('400.00'))
+        # Tolerance: ±1 cent for the 30.44 multiplication
+        self.assertAlmostEqual(
+            float(result['avg_monthly']), 12176.00, delta=0.01
+        )
+
+    def test_duplicate_dates_not_double_counted(self):
+        """Two workers working the same date = 1 distinct date, not 2."""
+        from core.views import _company_cost_velocity
+        admin = User.objects.create_user(username='admin-cv2', is_staff=True)
+        project = Project.objects.create(name='P2')
+        w1 = Worker.objects.create(name='X', id_number='X1', monthly_salary=Decimal('4000'))
+        w2 = Worker.objects.create(name='Y', id_number='Y1', monthly_salary=Decimal('4000'))
+        log = WorkLog.objects.create(
+            date=datetime.date(2026, 3, 1), project=project, supervisor=admin,
+        )
+        log.workers.add(w1, w2)
+        result = _company_cost_velocity()
+        self.assertEqual(result['working_days'], 1)  # not 2

core/views.py

@@ -216,6 +216,42 @@ def _compute_outstanding(project_ids=None, team_ids=None):
     }
 
 
+# =============================================================================
+# === COMPANY COST VELOCITY ===
+# Lifetime "what does a typical FoxFitt working day cost us?" metric.
+# Denominator = COUNT(DISTINCT work_log.date) — true working days, not
+# calendar days (rain days, weekends, permit delays don't dilute the rate).
+# Used by the hero KPI band on the payroll report.
+# =============================================================================
+
+def _company_cost_velocity():
+    """Return company-wide avg daily and monthly labour cost (lifetime)."""
+    # Total lifetime labour cost: sum of (worker.daily_rate) over every
+    # (log, worker) pair that has ever been logged.
+    total_cost = Decimal('0.00')
+    for wl in WorkLog.objects.prefetch_related('workers').all():
+        for worker in wl.workers.all():
+            total_cost += worker.daily_rate
+
+    # Distinct work-log dates = working days
+    working_days = WorkLog.objects.values('date').distinct().count()
+
+    if working_days == 0:
+        avg_daily = Decimal('0.00')
+    else:
+        avg_daily = (total_cost / working_days).quantize(Decimal('0.01'))
+
+    # 30.44 = 365.25 / 12 — standard month-length approximation.
+    # Keeps annualised totals correct on average.
+    avg_monthly = (avg_daily * Decimal('30.44')).quantize(Decimal('0.01'))
+
+    return {
+        'avg_daily': avg_daily,
+        'avg_monthly': avg_monthly,
+        'working_days': working_days,
+    }
+
+
 # === HOME DASHBOARD ===
 # The main page users see after logging in. Shows different content
 # depending on whether the user is an admin or supervisor.