From b5da55bb1aa926bd1297871965a800f9dd4c0f9b Mon Sep 17 00:00:00 2001
From: Adrian Kumpf <adrian.kumpf@posteo.de>
Date: Sun, 4 Oct 2020 11:13:16 +0200
Subject: [PATCH] Test cost calculation for negative cost

---
 test/teslamate/log/log_charging_test.exs | 28 ++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/test/teslamate/log/log_charging_test.exs b/test/teslamate/log/log_charging_test.exs
index 40eb027aec4..13d30b98c48 100644
--- a/test/teslamate/log/log_charging_test.exs
+++ b/test/teslamate/log/log_charging_test.exs
@@ -543,6 +543,34 @@ defmodule TeslaMate.LogChargingTest do
       assert cproc.cost == Decimal.new("0.00")
     end
 
+
+    test "cost per unit can be negative" do
+      car = car_fixture()
+
+      assert %GeoFence{id: id} =
+               geofence_fixture(%{
+                 latitude: 50.1121,
+                 longitude: 11.597,
+                 radius: 50,
+                 cost_per_unit: -0.15,
+                 session_fee: 0.0
+               })
+
+      assert {:ok, cproc} =
+               log_charging_process(charges_fixture(:phases_nil),
+                 car: car,
+                 attrs: %{
+                   date: DateTime.utc_now(),
+                   latitude: 50.112198,
+                   longitude: 11.597669
+                 }
+               )
+
+      assert cproc.charge_energy_added == Decimal.from_float(12.77)
+      assert cproc.charge_energy_used == Decimal.from_float(12.46)
+      assert cproc.cost == Decimal.new("-1.92")
+    end
+
     test "sets charge cost to zero if free supercharging is enabled" do
       alias TeslaMate.Settings