refactor! don't use ctx for policy evaluator (#140)

* refactor! don't use ctx for policy evaluator

internal/test/test.go

@@ -6,16 +6,14 @@ import (
 	"path/filepath"
 	"testing"
 
-	"github.com/docker/attest/pkg/policy"
 	"github.com/docker/attest/pkg/signerverifier"
 	"github.com/docker/attest/pkg/tlog"
 	"github.com/secure-systems-lab/go-securesystemslib/dsse"
 )
 
 const (
-	UseMockTL     = true
-	UseMockKMS    = true
-	UseMockPolicy = true
+	UseMockTL  = true
+	UseMockKMS = true
 
 	AWSRegion    = "us-east-1"
 	AWSKMSKeyARN = "arn:aws:kms:us-east-1:175142243308:alias/doi-signing" // sandbox
@@ -57,15 +55,6 @@ func Setup(t *testing.T) (context.Context, dsse.SignerVerifier) {
 
 	ctx := tlog.WithTL(context.Background(), tl)
 
-	var policyEvaluator policy.Evaluator
-	if UseMockPolicy {
-		policyEvaluator = policy.GetMockPolicy()
-	} else {
-		policyEvaluator = policy.NewRegoEvaluator(true)
-	}
-
-	ctx = policy.WithPolicyEvaluator(ctx, policyEvaluator)
-
 	var signer dsse.SignerVerifier
 	var err error
 	if UseMockKMS {