From f22ba928e066572b31d81878231c50d50b416937 Mon Sep 17 00:00:00 2001
From: Phil Elson <philip.elson@cern.ch>
Date: Fri, 6 Aug 2021 15:16:48 +0200
Subject: [PATCH] Ensure that 0 is always one of the state change times.

---
 cara/models.py                                |  2 +-
 cara/tests/models/test_concentration_model.py | 18 +++++++++---------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/cara/models.py b/cara/models.py
index 9d202391..51fc2bbf 100644
--- a/cara/models.py
+++ b/cara/models.py
@@ -769,7 +769,7 @@ class ConcentrationModel:
         the times at which their state changes.
 
         """
-        state_change_times = set()
+        state_change_times = {0.}
         state_change_times.update(self.infected.presence.transition_times())
         state_change_times.update(self.ventilation.transition_times())
         return sorted(state_change_times)
diff --git a/cara/tests/models/test_concentration_model.py b/cara/tests/models/test_concentration_model.py
index b5895f21..46e7e88e 100644
--- a/cara/tests/models/test_concentration_model.py
+++ b/cara/tests/models/test_concentration_model.py
@@ -53,7 +53,7 @@ def test_concentration_model_vectorisation(override_params):
 
 @pytest.fixture
 def simple_conc_model():
-    interesting_times = models.SpecificInterval(([0., 1.], [1.1, 1.999], [2., 3.]), )
+    interesting_times = models.SpecificInterval(([0.5, 1.], [1.1, 2], [2., 3.]), )
     return models.ConcentrationModel(
         models.Room(75),
         models.AirChange(interesting_times, 100),
@@ -71,14 +71,14 @@ def simple_conc_model():
 @pytest.mark.parametrize(
     "time, expected_last_state_change", [
         [-15., 0.],  # Out of range goes to the first state.
-        [0., 0],
-        [1., 0],
+        [0., 0.],
+        [0.5, 0.0],
+        [0.51, 0.5],
+        [1., 0.5],
         [1.05, 1.],
         [1.1, 1.],
         [1.11, 1.1],
-        [1.999, 1.1],
-        [1.9991, 1.999],
-        [2., 1.999],
+        [2., 1.1],
         [2.1, 2],
         [3., 2],
         [15., 3.],  # Out of range goes to the last state.
@@ -94,12 +94,12 @@ def test_last_state_change_time(
 
 @pytest.mark.parametrize(
     "time, expected_next_state_change", [
-        [0, 0],
+        [0.0, 0.0],
+        [0.5, 0.5],
         [1, 1],
         [1.05, 1.1],
         [1.1, 1.1],
-        [1.11, 1.999],
-        [1.9991, 2],
+        [1.11, 2],
         [2, 2],
         [2.1, 3],
         [3, 3],