Add feature manager (#2633)

* add feature manager

version/testing.go

@@ -0,0 +1,43 @@
+package version
+
+import (
+	"fmt"
+	"testing"
+
+	gvers "github.com/hashicorp/go-version"
+	"github.com/stretchr/testify/require"
+)
+
+// EnableFeatureForTest enables a feature for the current binary version
+func EnableFeatureForTest(t *testing.T, feature Feature) {
+	require := require.New(t)
+	version, err := GetReleaseVersion()
+	require.NoError(err)
+	EnableFeatureOnVersionForTest(t, version, feature)
+}
+
+// EnableFeatureForTest modifies the feature map to enable a feature for a version.
+// This is intended to be used for testing before release of a version
+// Test cleanup will reset the feature map to the original feature constraint
+// Note: running any tests in parallel while using this function WILL result in surprising
+// behavior because this modifies the global feature map
+func EnableFeatureOnVersionForTest(t *testing.T, version *gvers.Version, feature Feature) {
+	featConstraint, ok := featureMap[feature]
+	require := require.New(t)
+	require.True(ok)
+
+	versionNumber := version.String()
+	newConstraint, err := gvers.NewConstraint(fmt.Sprintf(">= %s", versionNumber))
+	require.NoError(err)
+
+	meta := metadataStringToMetadata(version.Metadata())
+	featureMap[feature] = MetadataConstraint{
+		MetaInfo:    []Metadata{meta},
+		Constraints: newConstraint,
+	}
+
+	resetFunc := func() {
+		featureMap[feature] = featConstraint
+	}
+	t.Cleanup(resetFunc)
+}