Add unittests for lower integral limit

tests/constraint_tests.py

@@ -904,6 +904,29 @@ def test_flow_without_emission_for_emission_constraint_no_error(self):
 
         self.compare_lp_files("emission_limit_no_error.lp", my_om=om)
 
+    def test_flow_without_emission_for_emission_constraint_lower(self):
+        """Test that no error is thrown if no flows are explicitly passed"""
+        bel = solph.buses.Bus(label="electricityBus")
+        source1 = solph.components.Source(
+            label="source1",
+            outputs={
+                bel: solph.flows.Flow(
+                    nominal_value=100,
+                    custom_attributes={"emission_factor": 0.8},
+                )
+            },
+        )
+        source2 = solph.components.Source(
+            label="source2", outputs={bel: solph.flows.Flow(nominal_value=100)}
+        )
+        self.energysystem.add(bel, source1, source2)
+        om = self.get_om()
+        solph.constraints.generic_integral_limit(
+            om, keyword="emission_factor", lower_limit=777
+        )
+
+        self.compare_lp_files("emission_limit_lower.lp", my_om=om)
+
     def test_equate_variables_constraint(self):
         """Testing the equate_variables function in the constraint module."""
         bus1 = solph.buses.Bus(label="Bus1")

tests/lp_files/emission_limit_lower.lp

@@ -0,0 +1,38 @@
+\* Source Pyomo model name=Model *\
+
+min 
+objective:
++0 ONE_VAR_CONSTANT
+
+s.t.
+
+c_l_integral_limit_emission_factor_lower_limit_:
++0.8 flow(source1_electricityBus_0)
++0.8 flow(source1_electricityBus_1)
++0.8 flow(source1_electricityBus_2)
+>= 777
+
+c_e_BusBlock_balance(electricityBus_0)_:
++1 flow(source1_electricityBus_0)
++1 flow(source2_electricityBus_0)
+= 0
+
+c_e_BusBlock_balance(electricityBus_1)_:
++1 flow(source1_electricityBus_1)
++1 flow(source2_electricityBus_1)
+= 0
+
+c_e_BusBlock_balance(electricityBus_2)_:
++1 flow(source1_electricityBus_2)
++1 flow(source2_electricityBus_2)
+= 0
+
+bounds
+   1 <= ONE_VAR_CONSTANT <= 1
+   0 <= flow(source1_electricityBus_0) <= 100
+   0 <= flow(source1_electricityBus_1) <= 100
+   0 <= flow(source1_electricityBus_2) <= 100
+   0 <= flow(source2_electricityBus_0) <= 100
+   0 <= flow(source2_electricityBus_1) <= 100
+   0 <= flow(source2_electricityBus_2) <= 100
+end

tests/test_constraints_module.py

@@ -1,9 +1,11 @@
+import pytest
+
 import pandas as pd
 
 from oemof import solph
 
 
-def test_special():
+def test_integral_limit_wrapper():
     date_time_index = pd.date_range("1/1/2012", periods=5, freq="h")
     energysystem = solph.EnergySystem(
         timeindex=date_time_index,
@@ -22,9 +24,10 @@ def test_special():
     flow_with_keyword = {
         (src1, bel): flow1,
     }
-    solph.constraints.generic_integral_limit(
-        model, "my_factor", flow_with_keyword, limit=777
-    )
+    with pytest.warns(FutureWarning):
+        solph.constraints.generic_integral_limit(
+            model, "my_factor", flow_with_keyword, limit=777
+        )
 
 
 def test_something_else():