Misc edits to resolve bugs in pycoek usage

Author: whart222

Diff for: lib/pyomo_coek/pyomo_coek/components_only/__init__.py

@@ -7,7 +7,7 @@
 from .linear_expression import LinearExpression
 from pyomo.core.base.block import Block
 from pyomo.core.base.PyomoModel import ConcreteModel
-from pyomo.core.base.set import RangeSet, \
+from pyomo.core.base.set import Set, RangeSet, \
     Reals, \
     PositiveReals, \
     NonPositiveReals, \

Diff for: lib/pyomo_coek/pyomo_coek/components_only/solvers.py

@@ -70,6 +70,8 @@ def __init__(self, solver_name):
         self.solution_loader = MySolutionLoader(None, None, None, None)
 
     def available(self):
+        if self._opt is None:
+            return self.Availability.NotFound
         if self._opt.available:
             return self.Availability.FullLicense
         else:

Diff for: lib/pyomo_coek/pyomo_coek/test/level1/test_solver.py

@@ -6,6 +6,7 @@
 
 def test_available1(pyomo_module):
     opt = pyomo_module.SolverFactory("bad_pyomo_solvername")
+    # TODO - resolve this inconsistency in the API
     assert not opt.available(False)
 
 
@@ -27,7 +28,7 @@ def test_gurobi(pyomo_module):
     m.o = pyomo_module.Objective(expr=m.x0 + m.x1)
 
     opt = pyomo_module.SolverFactory("coek_gurobi")
-    if opt.available(False):
+    if opt.available():
         res = opt.solve(m)
         pyo.check_optimal_termination(m)
 
@@ -39,6 +40,6 @@ def test_ipopt(pyomo_module):
     m.o = pyomo_module.Objective(expr=m.x0 + m.x1)
 
     opt = pyomo_module.SolverFactory("coek_ipopt")
-    if opt.available(False):
+    if opt.available():
         res = opt.solve(m)
         pyo.check_optimal_termination(m)