fix dimacs variable source

Signed-off-by: Per Goncalves da Silva <pegoncal@redhat.com>

cmd/dimacs/dimacs_constraints.go

@@ -28,6 +28,7 @@ func (d *ConstraintGenerator) GetVariables(_ context.Context) ([]deppy.Variable,
 	for _, id := range d.dimacs.variables {
 		variable := input.NewSimpleVariable(deppy.IdentifierFromString(id))
 		variables = append(variables, variable)
+		varMap[variable.Identifier()] = variable
 	}
 
 	// create constraints out of the clauses

cmd/dimacs/dimacs_test.go

@@ -2,8 +2,11 @@ package dimacs_test
 
 import (
 	"bytes"
+	"context"
 	"testing"
 
+	"github.com/operator-framework/deppy/pkg/deppy"
+
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 
@@ -34,3 +37,24 @@ var _ = Describe("Dimacs", func() {
 		Expect(d.Clauses()).To(Equal([]string{"1 2 3"}))
 	})
 })
+
+var _ = Describe("Dimacs Variable Source", func() {
+	It("should create variables for a dimacs problem", func() {
+		problem := "p cnf 3 1\n1 2 3 0\n"
+		d, err := dimacs.NewDimacs(bytes.NewReader([]byte(problem)))
+		Expect(err).ToNot(HaveOccurred())
+		vs := dimacs.NewDimacsVariableSource(d)
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+		variables, err := vs.GetVariables(ctx)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(variables).To(HaveLen(3))
+
+		Expect(variables[0].Identifier()).To(Equal(deppy.Identifier("1")))
+		Expect(variables[0].Constraints()).To(HaveLen(1))
+		Expect(variables[1].Identifier()).To(Equal(deppy.Identifier("2")))
+		Expect(variables[1].Constraints()).To(HaveLen(1))
+		Expect(variables[2].Identifier()).To(Equal(deppy.Identifier("3")))
+		Expect(variables[2].Constraints()).To(BeEmpty())
+	})
+})