feat: add NewAppraisal function

ear_appraisal.go

@@ -1,4 +1,4 @@
-// Copyright 2023 Contributors to the Veraison project.
+// Copyright 2023-2026 Contributors to the Veraison project.
 // SPDX-License-Identifier: Apache-2.0
 
 package ear
@@ -25,6 +25,17 @@ type Appraisal struct {
 	AppraisalExtensions
 }
 
+// NewAppraisal returns a new Appraisal with its status set to TrustTierNone
+// and all its claims set to NoClaim.
+func NewAppraisal() *Appraisal {
+	status := TrustTierNone
+
+	return &Appraisal{
+		Status:      &status,
+		TrustVector: &TrustVector{},
+	}
+}
+
 // AppraisalExtensions contains any proprietary claims that can be optionally
 // attached to the Appraisal.  For now only veraison-specific extensions are
 // supported.

ear_appraisal_test.go

@@ -91,3 +91,13 @@ func TestAppraisalExtensions_GetKeyAttestation_fail_akpub_no_b64url(t *testing.T
 	_, err := tv.GetKeyAttestation()
 	assert.EqualError(t, err, `"ear.veraison.key-attestation" malformed: decoding "akpub": illegal base64 data at input byte 84`)
 }
+
+func TestNewAppraisal(t *testing.T) {
+	appraisal := NewAppraisal()
+
+	assert.Equal(t, TrustTierNone, *appraisal.Status)
+
+	for _, claim := range appraisal.TrustVector.AsMap() {
+		assert.Equal(t, NoClaim, claim)
+	}
+}