feat: complete 15-minute optimization support

tests/test_interpolator.py

@@ -0,0 +1,30 @@
+import pytest
+
+from akkudoktoreos.prediction.interpolator import get_eos_load_interpolator
+
+
+def test_quarter_hour_energy_is_converted_back_to_same_mean_power():
+    """Splitting hourly energy must not change the minute-load probability lookup."""
+    interpolator = get_eos_load_interpolator()
+    hourly_load_wh = 800.0
+    hourly_pv_wh = 1200.0
+    slot_duration_h = 0.25
+
+    hourly = interpolator.calculate_self_consumption(hourly_load_wh, hourly_pv_wh)
+    quarter_hour = interpolator.calculate_self_consumption(
+        (hourly_load_wh / 4) / slot_duration_h,
+        (hourly_pv_wh / 4) / slot_duration_h,
+    )
+
+    assert quarter_hour == pytest.approx(hourly)
+
+
+def test_load_above_probability_grid_uses_highest_supported_distribution():
+    """Out-of-range household load must not make self-consumption jump to zero."""
+    interpolator = get_eos_load_interpolator()
+
+    at_boundary = interpolator.calculate_self_consumption(3450.0, 5000.0)
+    above_boundary = interpolator.calculate_self_consumption(4000.0, 5000.0)
+
+    assert above_boundary == pytest.approx(at_boundary)
+    assert above_boundary > 0.99