Move policy mock for external use (#16)

pkg/policy/mock.go

@@ -0,0 +1,40 @@
+package policy
+
+import (
+	"context"
+
+	"github.com/docker/attest/pkg/oci"
+	"github.com/open-policy-agent/opa/rego"
+)
+
+type MockPolicyEvaluator struct {
+	EvaluateFunc func(ctx context.Context, resolver oci.AttestationResolver, policy []*PolicyFile, input *PolicyInput) (*rego.ResultSet, error)
+}
+
+func (pe *MockPolicyEvaluator) Evaluate(ctx context.Context, resolver oci.AttestationResolver, policy []*PolicyFile, input *PolicyInput) (*rego.ResultSet, error) {
+	if pe.EvaluateFunc != nil {
+		return pe.EvaluateFunc(ctx, resolver, policy, input)
+	}
+	return AllowedResult(), nil
+}
+
+func GetMockPolicy() PolicyEvaluator {
+	return &MockPolicyEvaluator{
+		EvaluateFunc: func(ctx context.Context, resolver oci.AttestationResolver, pfs []*PolicyFile, input *PolicyInput) (*rego.ResultSet, error) {
+			return AllowedResult(), nil
+		},
+	}
+}
+
+func AllowedResult() *rego.ResultSet {
+	return &rego.ResultSet{
+		{
+			Bindings: rego.Vars{},
+			Expressions: []*rego.ExpressionValue{
+				{
+					Value: true,
+				},
+			},
+		},
+	}
+}