[#480] Add fuzzing tests

Signed-off-by: Roman Ognev <r.ognev@yadro.com>

api/handler/head_test.go

@@ -119,21 +119,25 @@ func TestIsAvailableToResolve(t *testing.T) {
 	}
 }
 
-func newTestAccessBox(t *testing.T, key *keys.PrivateKey) *accessbox.Box {
+func newTestAccessBox(key *keys.PrivateKey) (*accessbox.Box, error) {
 	var err error
 	if key == nil {
 		key, err = keys.NewPrivateKey()
-		require.NoError(t, err)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	var btoken bearer.Token
 	btoken.SetImpersonate(true)
 	err = btoken.Sign(key.PrivateKey)
-	require.NoError(t, err)
+	if err != nil {
+		return nil, err
+	}
 
 	return &accessbox.Box{
 		Gate: &accessbox.GateData{
 			BearerToken: &btoken,
 		},
-	}
+	}, nil
 }