Add SCIP solver for testing

.github/actions/setup-idaes/action.yml

@@ -42,3 +42,9 @@ runs:
         echo '::group::Output of "idaes get-extensions" command'
         idaes get-extensions --extra petsc --verbose
         echo '::endgroup::'
+    - name: Install SCIP from AMPL
+      shell: bash -l {0}
+      run: |
+        echo '::group::Output of "pip install ampl_module_scip" command'
+        ${{ inputs.install-command }} --index-url https://pypi.ampl.com ampl_module_scip
+        echo '::endgroup::'

idaes/core/util/testing.py

@@ -21,8 +21,13 @@
 __author__ = "Andrew Lee"
 
 
+import os
+from typing import Callable, Union
+
 from pyomo.environ import Constraint, Set, units, Var
 from pyomo.common.config import ConfigBlock
+from pyomo.common import Executable
+from pyomo.common.dependencies import attempt_import
 
 from idaes.core import (
     declare_process_block_class,
@@ -409,3 +414,36 @@
             return MaterialFlowBasis.mass
         else:
             return MaterialFlowBasis.other
+
+
+def _enable_scip_solver_for_testing(
+    name: str = "scip",
+) -> Union[Callable[[], None], None]:
+    ampl_module_scip, is_available = attempt_import("ampl_module_scip")
+    if not is_available:
+        _log.warning(
+            "ampl_module_scip must be installed to enable SCIP solver for testing"
+        )
+        return None
+
+    new_path_entry = ampl_module_scip.bin_dir
+    # TODO prepending new_path_entry to PATH means that the "testing" SCIP will "shadow"
+    # existing executable directories already on PATH
+    # this behavior would match the (implied) semantics of this function, i.e.
+    # "enable SCIP solver used for testing (at the expense of other non-testing SCIP executables)"
+    os.environ["PATH"] = os.pathsep.join([new_path_entry, os.environ["PATH"]])
+    Executable.rehash()
+
+    def remove_from_path():
+        path_as_list = os.environ["PATH"].split(os.pathsep)
+
+        try:
+            path_as_list.remove(new_path_entry)
+        except ValueError:
+            # not in PATH
+            pass
+        else:
+            os.environ["PATH"] = os.pathsep.join(path_as_list)
+            Executable.rehash()
+
+    return remove_from_path

idaes/core/util/tests/test_model_diagnostics.py

@@ -77,10 +77,24 @@
     _write_report_section,
     _collect_model_statistics,
 )
+from idaes.core.util.testing import _enable_scip_solver_for_testing
+
 
 __author__ = "Alex Dowling, Douglas Allan, Andrew Lee"
 
-solver_available = SolverFactory("scip").available()
+
+@pytest.fixture(scope="module")
+def scip_solver():
+    solver = SolverFactory("scip")
+    undo_changes = None
+
+    if not solver.available():
+        undo_changes = _enable_scip_solver_for_testing()
+    if not solver.available():
+        pytest.skip(reason="SCIP solver not available")
+    yield solver
+    if undo_changes is not None:
+        undo_changes()
 
 
 @pytest.fixture
@@ -1790,27 +1804,26 @@ def test_identify_candidates(self, model):
 
     @pytest.mark.solver
     @pytest.mark.component
-    @pytest.mark.skipif(not solver_available, reason="SCIP is not available")
-    def test_solve_candidates_milp(self, model):
+    def test_solve_candidates_milp(self, model, scip_solver):
         dh = DegeneracyHunter2(model)
         dh._prepare_candidates_milp()
         dh._solve_candidates_milp()
 
-        assert value(dh.candidates_milp.nu[0]) == pytest.approx(-1e-05, rel=1e-5)
-        assert value(dh.candidates_milp.nu[1]) == pytest.approx(1e-05, rel=1e-5)
+        assert value(dh.candidates_milp.nu[0]) == pytest.approx(1e-05, rel=1e-5)
+        assert value(dh.candidates_milp.nu[1]) == pytest.approx(-1e-05, rel=1e-5)
 
         assert value(dh.candidates_milp.y_pos[0]) == pytest.approx(0, abs=1e-5)
-        assert value(dh.candidates_milp.y_pos[1]) == pytest.approx(1, rel=1e-5)
+        assert value(dh.candidates_milp.y_pos[1]) == pytest.approx(0, rel=1e-5)
 
-        assert value(dh.candidates_milp.y_neg[0]) == pytest.approx(-0, abs=1e-5)
-        assert value(dh.candidates_milp.y_neg[1]) == pytest.approx(-0, abs=1e-5)
+        assert value(dh.candidates_milp.y_neg[0]) == pytest.approx(0, abs=1e-5)
+        assert value(dh.candidates_milp.y_neg[1]) == pytest.approx(1, abs=1e-5)
 
         assert value(dh.candidates_milp.abs_nu[0]) == pytest.approx(1e-05, rel=1e-5)
         assert value(dh.candidates_milp.abs_nu[1]) == pytest.approx(1e-05, rel=1e-5)
 
         assert dh.degenerate_set == {
-            model.con2: -1e-05,
-            model.con5: 1e-05,
+            model.con2: value(dh.candidates_milp.nu[0]),
+            model.con5: value(dh.candidates_milp.nu[1]),
         }
 
     @pytest.mark.unit
@@ -1840,8 +1853,7 @@ def test_solve_ids_milp(self, model):
 
     @pytest.mark.solver
     @pytest.mark.component
-    @pytest.mark.skipif(not solver_available, reason="SCIP is not available")
-    def test_solve_ids_milp(self, model):
+    def test_solve_ids_milp(self, model, scip_solver):
         dh = DegeneracyHunter2(model)
         dh._prepare_ids_milp()
         ids_ = dh._solve_ids_milp(cons=model.con2)
@@ -1859,8 +1871,7 @@ def test_solve_ids_milp(self, model):
 
     @pytest.mark.solver
     @pytest.mark.component
-    @pytest.mark.skipif(not solver_available, reason="SCIP is not available")
-    def test_find_irreducible_degenerate_sets(self, model):
+    def test_find_irreducible_degenerate_sets(self, model, scip_solver):
         dh = DegeneracyHunter2(model)
         dh.find_irreducible_degenerate_sets()
 
@@ -1871,8 +1882,7 @@ def test_find_irreducible_degenerate_sets(self, model):
 
     @pytest.mark.solver
     @pytest.mark.component
-    @pytest.mark.skipif(not solver_available, reason="SCIP is not available")
-    def test_report_irreducible_degenerate_sets(self, model):
+    def test_report_irreducible_degenerate_sets(self, model, scip_solver):
         stream = StringIO()
 
         dh = DegeneracyHunter2(model)
@@ -1898,8 +1908,7 @@ def test_report_irreducible_degenerate_sets(self, model):
 
     @pytest.mark.solver
     @pytest.mark.component
-    @pytest.mark.skipif(not solver_available, reason="SCIP is not available")
-    def test_report_irreducible_degenerate_sets_none(self, model):
+    def test_report_irreducible_degenerate_sets_none(self, model, scip_solver):
         stream = StringIO()
 
         # Delete degenerate constraint

idaes/core/util/tests/test_scip_for_testing.py

@@ -0,0 +1,39 @@
+#################################################################################
+# The Institute for the Design of Advanced Energy Systems Integrated Platform
+# Framework (IDAES IP) was produced under the DOE Institute for the
+# Design of Advanced Energy Systems (IDAES).
+#
+# Copyright (c) 2018-2023 by the software owners: The Regents of the
+# University of California, through Lawrence Berkeley National Laboratory,
+# National Technology & Engineering Solutions of Sandia, LLC, Carnegie Mellon
+# University, West Virginia University Research Corporation, et al.
+# All rights reserved.  Please see the files COPYRIGHT.md and LICENSE.md
+# for full copyright and license information.
+#################################################################################
+import os
+
+import pytest
+from pyomo.environ import SolverFactory
+
+from idaes.core.util.testing import _enable_scip_solver_for_testing
+
+
+ampl_module_scip = pytest.importorskip(
+    "ampl_module_scip", reason="'ampl_module_scip' not available"
+)
+
+
+@pytest.mark.unit
+def test_path_manipulation():
+    path_before_enabling = str(os.environ["PATH"])
+
+    func_to_revert_changes = _enable_scip_solver_for_testing()
+    path_after_enabling = str(os.environ["PATH"])
+    sf = SolverFactory("scip")
+    assert len(path_after_enabling) > len(path_before_enabling)
+    assert str(ampl_module_scip.bin_dir) in str(sf.executable())
+    assert sf.available()
+
+    func_to_revert_changes()
+    path_after_reverting = str(os.environ["PATH"])
+    assert path_after_reverting == path_before_enabling

setup.py

@@ -127,7 +127,7 @@ def __getitem__(self, key):
     # Put abstract (non-versioned) deps here.
     # Concrete dependencies go in requirements[-dev].txt
     install_requires=[
-        "pyomo>=6.6.2",
+        "pyomo @ git+https://github.com/IDAES/[email protected]",
         "pint",  # required to use Pyomo units
         "networkx",  # required to use Pyomo network
         "numpy",