feat: reorganize packages

pkg/meta/meta_test.go

@@ -0,0 +1,23 @@
+package meta_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/ucan-wg/go-ucan/pkg/meta"
+	"gotest.tools/v3/assert"
+)
+
+func TestMeta_Add(t *testing.T) {
+	t.Parallel()
+
+	type Unsupported struct{}
+
+	t.Run("error if not primative or Node", func(t *testing.T) {
+		t.Parallel()
+
+		err := (&meta.Meta{}).Add("invalid", &Unsupported{})
+		require.ErrorIs(t, err, meta.ErrUnsupported)
+		assert.ErrorContains(t, err, "*github.com/ucan-wg/go-ucan/pkg/meta_test.Unsupported")
+	})
+}