Adds sort subpackage to catalogmetadata

Signed-off-by: Mikalai Radchuk <mradchuk@redhat.com>

internal/catalogmetadata/sort/sort.go

@@ -0,0 +1,33 @@
+package sort
+
+import (
+	"github.com/operator-framework/operator-controller/internal/catalogmetadata"
+)
+
+// ByVersion is a sort "less" function that orders bundles
+// in inverse version order (higher versions on top).
+func ByVersion(b1, b2 *catalogmetadata.Bundle) bool {
+	ver1, err1 := b1.Version()
+	ver2, err2 := b2.Version()
+	if err1 != nil || err2 != nil {
+		return compareErrors(err1, err2) < 0
+	}
+
+	// Check for "greater than" because
+	// we want higher versions on top
+	return ver1.GT(*ver2)
+}
+
+// compareErrors returns 0 if both errors are either nil or not nil
+// -1 if err1 is nil and err2 is not nil
+// +1 if err1 is not nil and err2 is nil
+func compareErrors(err1 error, err2 error) int {
+	if err1 != nil && err2 == nil {
+		return 1
+	}
+
+	if err1 == nil && err2 != nil {
+		return -1
+	}
+	return 0
+}

internal/catalogmetadata/sort/sort_test.go

@@ -0,0 +1,83 @@
+package sort_test
+
+import (
+	"encoding/json"
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/operator-framework/operator-registry/alpha/declcfg"
+	"github.com/operator-framework/operator-registry/alpha/property"
+
+	"github.com/operator-framework/operator-controller/internal/catalogmetadata"
+	catalogsort "github.com/operator-framework/operator-controller/internal/catalogmetadata/sort"
+)
+
+func TestByVersion(t *testing.T) {
+	b1 := &catalogmetadata.Bundle{Bundle: declcfg.Bundle{
+		Name: "package1.v1.0.0",
+		Properties: []property.Property{
+			{
+				Type:  property.TypePackage,
+				Value: json.RawMessage(`{"packageName": "package1", "version": "1.0.0"}`),
+			},
+		},
+	}}
+	b2 := &catalogmetadata.Bundle{Bundle: declcfg.Bundle{
+		Name: "package1.v0.0.1",
+		Properties: []property.Property{
+			{
+				Type:  property.TypePackage,
+				Value: json.RawMessage(`{"packageName": "package1", "version": "0.0.1"}`),
+			},
+		},
+	}}
+	b3 := &catalogmetadata.Bundle{Bundle: declcfg.Bundle{
+		Name: "package1.v1.0.0-alpha+001",
+		Properties: []property.Property{
+			{
+				Type:  property.TypePackage,
+				Value: json.RawMessage(`{"packageName": "package1", "version": "1.0.0-alpha+001"}`),
+			},
+		},
+	}}
+	b4noVersion := &catalogmetadata.Bundle{Bundle: declcfg.Bundle{
+		Name: "package1.no-version",
+		Properties: []property.Property{
+			{
+				Type:  property.TypePackage,
+				Value: json.RawMessage(`{"packageName": "package1"}`),
+			},
+		},
+	}}
+	b5empty := &catalogmetadata.Bundle{Bundle: declcfg.Bundle{
+		Name: "package1.empty",
+	}}
+
+	t.Run("all bundles valid", func(t *testing.T) {
+		toSort := []*catalogmetadata.Bundle{b3, b2, b1}
+		sort.SliceStable(toSort, func(i, j int) bool {
+			return catalogsort.ByVersion(toSort[i], toSort[j])
+		})
+
+		assert.Len(t, toSort, 3)
+		assert.Equal(t, b1, toSort[0])
+		assert.Equal(t, b3, toSort[1])
+		assert.Equal(t, b2, toSort[2])
+	})
+
+	t.Run("some bundles are missing version", func(t *testing.T) {
+		toSort := []*catalogmetadata.Bundle{b3, b4noVersion, b2, b5empty, b1}
+		sort.SliceStable(toSort, func(i, j int) bool {
+			return catalogsort.ByVersion(toSort[i], toSort[j])
+		})
+
+		assert.Len(t, toSort, 5)
+		assert.Equal(t, b1, toSort[0])
+		assert.Equal(t, b3, toSort[1])
+		assert.Equal(t, b2, toSort[2])
+		assert.Equal(t, b4noVersion, toSort[3])
+		assert.Equal(t, b5empty, toSort[4])
+	})
+}