further test case

evrouting/charge/routing.py

@@ -142,6 +142,14 @@ def shortest_path(G: nx.Graph, charging_stations: set, s: Node, t: Node,
                         )
                     )
                 except ValueError:
+                    # Infeasible because last_cs might be an
+                    # dummy charging station. Therefore, the path might
+                    # be infeasible even though one could reach it with a full
+                    # battery, because charging is not possible at dummy
+                    # stations.
+                    #
+                    # That means, the SoC and thereby the range is restricted
+                    # to the SoC at the last cs (soc_last_cs).
                     pass
                 else:
                     if l_new == l_uns[n].peak_min():

tests/charge/test_charge_routing.py

@@ -3,17 +3,25 @@ from evrouting.charge import shortest_path
 from ..config import (
     edge_case,
     edge_case_start_node_no_cs,
+    edge_case_a_slow,
     init_config
 )
 
 
-def test_shortest_path_charge_at_s():
+def test_shortest_path_charge_at_s_and_a():
     """Charging at s."""
     path = shortest_path(**init_config(edge_case))
 
     assert path == 3.5
 
 
+def test_shortest_path_charge_at_s_only():
+    """Charging at s."""
+    path = shortest_path(**init_config(edge_case_a_slow))
+
+    assert path == 3
+
+
 def test_shortest_path_no_charge_s_path_t():
     """No charging at s but enough initial SoC to go to t directly."""
     conf = init_config(edge_case_start_node_no_cs)

tests/config.py

@@ -8,7 +8,11 @@ from evrouting.graph_tools import (
 )
 
 # List of configs
-config_list = ['edge_case', 'edge_case_start_node_no_cs']
+config_list = [
+    'edge_case',
+    'edge_case_start_node_no_cs',
+    'edge_case_a_slow'
+]
 
 edge_case = {
     'beta_s': 0,
@@ -28,6 +32,24 @@ edge_case = {
     ]
 }
 
+edge_case_a_slow = {
+    'beta_s': 0,
+    'beta_t': 0,
+    'U': 4,
+    's': 0,
+    't': 2,
+    'nodes': [
+        TemplateNode('s', charging_coeff=2),
+        TemplateNode('a', charging_coeff=1),
+        TemplateNode('t'),
+    ],
+    'edges': [
+        TemplateEdge(0, 1, distance=1, consumption=1),
+        TemplateEdge(0, 2, distance=1, consumption=4),
+        TemplateEdge(1, 2, distance=1, consumption=1),
+    ]
+}
+
 edge_case_start_node_no_cs = {
     'beta_s': 0,
     'beta_t': 0,