add more tufrootveriify tests

Signed-off-by: Meredith Lancaster <malancas@github.com>

pkg/cmd/attestation/tufrootverify/tufrootverify_test.go

@@ -4,11 +4,13 @@ import (
 	"bytes"
 	"testing"
 
+	"github.com/cli/cli/v2/pkg/cmd/attestation/test"
 	"github.com/cli/cli/v2/pkg/cmdutil"
 	"github.com/cli/cli/v2/pkg/iostreams"
 
 	"github.com/google/shlex"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestNewTUFRootVerifyCmd(t *testing.T) {
@@ -32,6 +34,11 @@ func TestNewTUFRootVerifyCmd(t *testing.T) {
 			cli:      "--mirror https://tuf-repo.github.com",
 			wantsErr: true,
 		},
+		{
+			name:     "Has all required flags",
+			cli:      "--mirror https://tuf-repo.github.com --root ../verification/embed/tuf-repo.github.com/root.json",
+			wantsErr: false,
+		},
 	}
 
 	for _, tc := range testcases {
@@ -55,3 +62,20 @@ func TestNewTUFRootVerifyCmd(t *testing.T) {
 		})
 	}
 }
+
+func TestTUFRootVerify(t *testing.T) {
+	mirror := "https://tuf-repo.github.com"
+	root := test.NormalizeRelativePath("../verification/embed/tuf-repo.github.com/root.json")
+
+	t.Run("successfully verifies TUF root", func(t *testing.T) {
+		err := tufRootVerify(mirror, root)
+		require.NoError(t, err)
+	})
+
+	t.Run("fails because the root cannot be found", func(t *testing.T) {
+		notFoundRoot := test.NormalizeRelativePath("./does/not/exist/root.json")
+		err := tufRootVerify(mirror, notFoundRoot)
+		require.Error(t, err)
+		require.ErrorContains(t, err, "failed to read root file")
+	})
+}