Add GetProblem method to Solution interface and DummySolution implementation

Co-authored-by: kwesiRutledge <[email protected]>

Author: Copilot

solution/dummy_solution.go

@@ -1,6 +1,9 @@
 package solution
 
-import solution_status "github.com/MatProGo-dev/MatProInterface.go/solution/status"
+import (
+	"github.com/MatProGo-dev/MatProInterface.go/problem"
+	solution_status "github.com/MatProGo-dev/MatProInterface.go/solution/status"
+)
 
 type DummySolution struct {
 	Values map[uint64]float64
@@ -11,6 +14,9 @@ type DummySolution struct {
 	// Whether or not the solution is within the optimality threshold
 	Status solution_status.SolutionStatus
 
+	// The optimization problem that this solution is for
+	Problem *problem.OptimizationProblem
+
 	// The optimality gap returned from the solver. For many solvers, this is
 	// the gap between the best possible solution with integer relaxation and
 	// the best integer solution found so far.
@@ -28,3 +34,7 @@ func (ds *DummySolution) GetValueMap() map[uint64]float64 {
 func (ds *DummySolution) GetStatus() solution_status.SolutionStatus {
 	return ds.Status
 }
+
+func (ds *DummySolution) GetProblem() *problem.OptimizationProblem {
+	return ds.Problem
+}

solution/solution.go

@@ -3,6 +3,7 @@ package solution
 import (
 	"fmt"
 
+	"github.com/MatProGo-dev/MatProInterface.go/problem"
 	solution_status "github.com/MatProGo-dev/MatProInterface.go/solution/status"
 	"github.com/MatProGo-dev/SymbolicMath.go/symbolic"
 )
@@ -20,6 +21,9 @@ type Solution interface {
 	// GetStatus
 	//
 	GetStatus() solution_status.SolutionStatus
+
+	// GetProblem returns the optimization problem that this solution is for
+	GetProblem() *problem.OptimizationProblem
 }
 
 func ExtractValueOfVariableWithID(s Solution, idx uint64) (float64, error) {

testing/solution/solution_test.go

@@ -4,6 +4,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/MatProGo-dev/MatProInterface.go/problem"
 	"github.com/MatProGo-dev/MatProInterface.go/solution"
 	solution_status "github.com/MatProGo-dev/MatProInterface.go/solution/status"
 	"github.com/MatProGo-dev/SymbolicMath.go/symbolic"
@@ -317,3 +318,62 @@ func TestSolution_FindValueOfExpression5(t *testing.T) {
 		)
 	}
 }
+
+/*
+TestSolution_GetProblem1
+Description:
+
+	This function tests whether we can retrieve the problem from a solution.
+*/
+func TestSolution_GetProblem1(t *testing.T) {
+	// Constants
+	p := problem.NewProblem("TestProblem1")
+	v1 := p.AddVariable()
+
+	tempSol := solution.DummySolution{
+		Values: map[uint64]float64{
+			v1.ID: 2.1,
+		},
+		Objective: 2.3,
+		Status:    solution_status.OPTIMAL,
+		Problem:   p,
+	}
+
+	// Algorithm
+	retrievedProblem := tempSol.GetProblem()
+
+	// Verify the problem is the same
+	if retrievedProblem != p {
+		t.Errorf("Expected GetProblem to return the same problem pointer")
+	}
+
+	if retrievedProblem.Name != "TestProblem1" {
+		t.Errorf("Expected problem name to be 'TestProblem1'; received %v", retrievedProblem.Name)
+	}
+}
+
+/*
+TestSolution_GetProblem2
+Description:
+
+	This function tests whether GetProblem returns nil when no problem is set.
+*/
+func TestSolution_GetProblem2(t *testing.T) {
+	// Constants
+	tempSol := solution.DummySolution{
+		Values: map[uint64]float64{
+			0: 2.1,
+		},
+		Objective: 2.3,
+		Status:    solution_status.OPTIMAL,
+		Problem:   nil,
+	}
+
+	// Algorithm
+	retrievedProblem := tempSol.GetProblem()
+
+	// Verify the problem is nil
+	if retrievedProblem != nil {
+		t.Errorf("Expected GetProblem to return nil when no problem is set")
+	}
+}