Add tests for legacy solution access

Author: FBumann

tests/test_math/test_legacy_solution_access.py

@@ -0,0 +1,158 @@
+"""Tests for legacy solution access patterns.
+
+These tests verify that CONFIG.Legacy.solution_access enables backward-compatible
+access to solution variables using the old naming convention.
+"""
+
+import numpy as np
+import pytest
+from numpy.testing import assert_allclose
+
+import flixopt as fx
+
+from .conftest import make_flow_system
+
+
+class TestLegacySolutionAccess:
+    """Tests for legacy solution access patterns."""
+
+    def test_effect_access(self, optimize):
+        """Test legacy effect access: solution['costs'] -> solution['effect|total'].sel(effect='costs')."""
+        fs = make_flow_system(2)
+        fs.add_elements(
+            fx.Bus('Heat'),
+            fx.Effect('costs', '€', is_standard=True, is_objective=True),
+            fx.Source('Src', outputs=[fx.Flow('heat', bus='Heat', size=10, effects_per_flow_hour=1)]),
+            fx.Sink('Snk', inputs=[fx.Flow('heat', bus='Heat', size=10, fixed_relative_profile=np.array([1, 1]))]),
+        )
+        fs = optimize(fs)
+
+        # Legacy access should work
+        legacy_result = fs.solution['costs'].item()
+        # New access
+        new_result = fs.solution['effect|total'].sel(effect='costs').item()
+
+        assert_allclose(legacy_result, new_result, rtol=1e-10)
+        assert_allclose(legacy_result, 20.0, rtol=1e-5)  # 2 timesteps * 10 flow * 1 cost
+
+    def test_flow_rate_access(self, optimize):
+        """Test legacy flow rate access: solution['Src(heat)|flow_rate'] -> solution['flow|rate'].sel(flow='Src(heat)')."""
+        fs = make_flow_system(2)
+        fs.add_elements(
+            fx.Bus('Heat'),
+            fx.Effect('costs', '€', is_standard=True, is_objective=True),
+            fx.Source('Src', outputs=[fx.Flow('heat', bus='Heat', size=10)]),
+            fx.Sink('Snk', inputs=[fx.Flow('heat', bus='Heat', size=10, fixed_relative_profile=np.array([1, 1]))]),
+        )
+        fs = optimize(fs)
+
+        # Legacy access should work
+        legacy_result = fs.solution['Src(heat)|flow_rate'].values[:-1]  # Exclude trailing NaN
+        # New access
+        new_result = fs.solution['flow|rate'].sel(flow='Src(heat)').values[:-1]
+
+        assert_allclose(legacy_result, new_result, rtol=1e-10)
+        assert_allclose(legacy_result, [10, 10], rtol=1e-5)
+
+    def test_flow_size_access(self, optimize):
+        """Test legacy flow size access: solution['Src(heat)|size'] -> solution['flow|size'].sel(flow='Src(heat)')."""
+        fs = make_flow_system(2)
+        fs.add_elements(
+            fx.Bus('Heat'),
+            fx.Effect('costs', '€', is_standard=True, is_objective=True),
+            fx.Source(
+                'Src',
+                outputs=[fx.Flow('heat', bus='Heat', size=fx.InvestParameters(fixed_size=50), effects_per_flow_hour=1)],
+            ),
+            fx.Sink('Snk', inputs=[fx.Flow('heat', bus='Heat', size=10, fixed_relative_profile=np.array([5, 5]))]),
+        )
+        fs = optimize(fs)
+
+        # Legacy access should work
+        legacy_result = fs.solution['Src(heat)|size'].item()
+        # New access
+        new_result = fs.solution['flow|size'].sel(flow='Src(heat)').item()
+
+        assert_allclose(legacy_result, new_result, rtol=1e-10)
+        assert_allclose(legacy_result, 50.0, rtol=1e-5)
+
+    def test_storage_charge_state_access(self, optimize):
+        """Test legacy storage charge state access: solution['Battery|charge_state'] -> solution['storage|charge'].sel(storage='Battery')."""
+        fs = make_flow_system(3)
+        fs.add_elements(
+            fx.Bus('Elec'),
+            fx.Effect('costs', '€', is_standard=True, is_objective=True),
+            fx.Source('Grid', outputs=[fx.Flow('elec', bus='Elec', size=100, effects_per_flow_hour=1)]),
+            fx.Storage(
+                'Battery',
+                charging=fx.Flow('charge', bus='Elec', size=10),
+                discharging=fx.Flow('discharge', bus='Elec', size=10),
+                capacity_in_flow_hours=50,
+                initial_charge_state=25,
+            ),
+            fx.Sink('Load', inputs=[fx.Flow('elec', bus='Elec', size=10, fixed_relative_profile=np.array([1, 1, 1]))]),
+        )
+        fs = optimize(fs)
+
+        # Legacy access should work
+        legacy_result = fs.solution['Battery|charge_state'].values
+        # New access
+        new_result = fs.solution['storage|charge'].sel(storage='Battery').values
+
+        assert_allclose(legacy_result, new_result, rtol=1e-10)
+        # Initial charge state is 25
+        assert legacy_result[0] == 25.0
+
+    def test_legacy_access_disabled_by_default(self):
+        """Test that legacy access is disabled when CONFIG.Legacy.solution_access is False."""
+        # Save current setting
+        original_setting = fx.CONFIG.Legacy.solution_access
+
+        try:
+            # Disable legacy access
+            fx.CONFIG.Legacy.solution_access = False
+
+            fs = make_flow_system(2)
+            fs.add_elements(
+                fx.Bus('Heat'),
+                fx.Effect('costs', '€', is_standard=True, is_objective=True),
+                fx.Source('Src', outputs=[fx.Flow('heat', bus='Heat', size=10, effects_per_flow_hour=1)]),
+                fx.Sink('Snk', inputs=[fx.Flow('heat', bus='Heat', size=10, fixed_relative_profile=np.array([1, 1]))]),
+            )
+            solver = fx.solvers.HighsSolver(log_to_console=False)
+            fs.optimize(solver)
+
+            # Legacy access should raise KeyError
+            with pytest.raises(KeyError):
+                _ = fs.solution['costs']
+
+            # New access should work
+            result = fs.solution['effect|total'].sel(effect='costs').item()
+            assert_allclose(result, 20.0, rtol=1e-5)
+
+        finally:
+            # Restore original setting
+            fx.CONFIG.Legacy.solution_access = original_setting
+
+    def test_legacy_access_emits_deprecation_warning(self, optimize):
+        """Test that legacy access emits DeprecationWarning."""
+        fs = make_flow_system(2)
+        fs.add_elements(
+            fx.Bus('Heat'),
+            fx.Effect('costs', '€', is_standard=True, is_objective=True),
+            fx.Source('Src', outputs=[fx.Flow('heat', bus='Heat', size=10, effects_per_flow_hour=1)]),
+            fx.Sink('Snk', inputs=[fx.Flow('heat', bus='Heat', size=10, fixed_relative_profile=np.array([1, 1]))]),
+        )
+        fs = optimize(fs)
+
+        import warnings
+
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter('always')
+            _ = fs.solution['costs']
+
+            # Should have exactly one DeprecationWarning
+            deprecation_warnings = [x for x in w if issubclass(x.category, DeprecationWarning)]
+            assert len(deprecation_warnings) == 1
+            assert 'Legacy solution access' in str(deprecation_warnings[0].message)
+            assert "solution['effect|total'].sel(effect='costs')" in str(deprecation_warnings[0].message)