add setter to the version scheme type (#25)

Fix #24

versionscheme.go

@@ -5,6 +5,7 @@ package swid
 
 import (
 	"encoding/xml"
+	"fmt"
 )
 
 // VersionScheme models the version-scheme type.
@@ -98,3 +99,12 @@ func (vs VersionScheme) MarshalXMLAttr(name xml.Name) (xml.Attr, error) {
 func (vs *VersionScheme) UnmarshalXMLAttr(attr xml.Attr) error {
 	return xmlAttrToCode(attr, stringToVersionScheme, &vs.val)
 }
+
+func (vs *VersionScheme) SetCode(v uint64) error {
+	if _, ok := versionSchemeToString[v]; ok {
+		vs.val = v
+		return nil
+	}
+
+	return fmt.Errorf("unknown version scheme %d", v)
+}

versionscheme_test.go

@@ -0,0 +1,58 @@
+// Copyright 2020 Contributors to the Veraison project.
+// SPDX-License-Identifier: Apache-2.0
+
+package swid
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestVersionScheme_Set(t *testing.T) {
+	tests := []struct {
+		name     string
+		tv       uint64
+		expected error
+	}{
+		{
+			name:     "known codepoints (1)",
+			tv:       VersionSchemeMultipartNumeric,
+			expected: nil,
+		},
+		{
+			name:     "known codepoints (2)",
+			tv:       VersionSchemeMultipartNumericSuffix,
+			expected: nil,
+		},
+		{
+			name:     "known codepoints (3)",
+			tv:       VersionSchemeAlphaNumeric,
+			expected: nil,
+		},
+		{
+			name:     "known codepoints (4)",
+			tv:       VersionSchemeDecimal,
+			expected: nil,
+		},
+		{
+			name:     "known codepoints (5)",
+			tv:       VersionSchemeSemVer,
+			expected: nil,
+		},
+		{
+			name:     "unknown codepoint",
+			tv:       19283937,
+			expected: errors.New("unknown version scheme 19283937"),
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var u VersionScheme
+			actual := u.SetCode(test.tv)
+			assert.Equal(t, test.expected, actual)
+		})
+	}
+}