add tests to backupParseRelsCmdFunc

also does some minor refactoring on the function to
make it testable and easier to follow

Author: vroldanbet

internal/cmd/backup.go

@@ -67,7 +67,9 @@ var (
 		Use:   "parse-relationships <filename>",
 		Short: "Extract the relationships from a backup file",
 		Args:  cobra.ExactArgs(1),
-		RunE:  backupParseRelsCmdFunc,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return backupParseRelsCmdFunc(cmd, os.Stdout, args)
+		},
 	}
 )
 
@@ -556,11 +558,12 @@ func backupParseRevisionCmdFunc(_ *cobra.Command, args []string) error {
 	return nil
 }
 
-func backupParseRelsCmdFunc(cmd *cobra.Command, args []string) error {
+func backupParseRelsCmdFunc(cmd *cobra.Command, out *os.File, args []string) error {
 	filename := "" // Default to stdin.
 	if len(args) > 0 {
 		filename = args[0]
 	}
+	prefix := cobrautil.MustGetString(cmd, "prefix-filter")
 
 	f, _, err := openRestoreFile(filename)
 	if err != nil {
@@ -573,15 +576,24 @@ func backupParseRelsCmdFunc(cmd *cobra.Command, args []string) error {
 	}
 
 	for rel, err := decoder.Next(); rel != nil && err == nil; rel, err = decoder.Next() {
-		if hasRelPrefix(rel, cobrautil.MustGetString(cmd, "prefix-filter")) {
-			relString, err := tuple.StringRelationship(rel)
-			if err != nil {
-				return err
-			}
-			relString = strings.Replace(relString, "@", " ", 1)
-			relString = strings.Replace(relString, "#", " ", 1)
-			fmt.Println(relString)
+		if !hasRelPrefix(rel, prefix) {
+			continue
+		}
+
+		relString, err := tuple.StringRelationship(rel)
+		if err != nil {
+			return err
+		}
+
+		if _, err = fmt.Fprintln(out, replaceRelString(relString)); err != nil {
+			return err
 		}
 	}
+
 	return nil
 }
+
+func replaceRelString(rel string) string {
+	rel = strings.Replace(rel, "@", " ", 1)
+	return strings.Replace(rel, "#", " ", 1)
+}

internal/cmd/backup_test.go

@@ -1,11 +1,25 @@
 package cmd
 
 import (
+	"os"
 	"testing"
 
+	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/require"
 )
 
+func init() {
+	zerolog.SetGlobalLevel(zerolog.Disabled)
+}
+
+const testSchema = `definition test/user {}\ndefinition resource {relation reader: test/user}\n`
+
+var testRelationships = []string{
+	`test/user:1#reader@test/resource:1`,
+	`test/user:2#reader@test/resource:2`,
+	`test/user:3#reader@test/resource:3`,
+}
+
 func TestFilterSchemaDefs(t *testing.T) {
 	for _, tt := range []struct {
 		name         string
@@ -99,3 +113,58 @@ func TestFilterSchemaDefs(t *testing.T) {
 		})
 	}
 }
+
+func TestBackupParseRelsCmdFunc(t *testing.T) {
+	for _, tt := range []struct {
+		name          string
+		filter        string
+		schema        string
+		relationships []string
+		output        []string
+		err           string
+	}{
+		{
+			name:          "basic test",
+			filter:        "test",
+			schema:        testSchema,
+			relationships: testRelationships,
+			output:        mapRelationshipTuplesToCLIOutput(t, testRelationships),
+		},
+		{
+			name:          "filters out",
+			filter:        "test",
+			schema:        testSchema,
+			relationships: append([]string{"foo/user:0#reader@foo/resource:0"}, testRelationships...),
+			output:        mapRelationshipTuplesToCLIOutput(t, testRelationships),
+		},
+		{
+			name:          "allows empty backup",
+			filter:        "test",
+			schema:        testSchema,
+			relationships: nil,
+			output:        nil,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			tt := tt
+			t.Parallel()
+
+			cmd := createTestCobraCommandWithFlagValue(t, "prefix-filter", tt.filter)
+			backupName := createTestBackup(t, tt.schema, tt.relationships)
+			f, err := os.CreateTemp("", "parse-output")
+			require.NoError(t, err)
+			defer func() {
+				_ = f.Close()
+			}()
+			t.Cleanup(func() {
+				_ = os.Remove(f.Name())
+			})
+
+			err = backupParseRelsCmdFunc(cmd, f, []string{backupName})
+			require.NoError(t, err)
+
+			lines := readLines(t, f.Name())
+			require.Equal(t, tt.output, lines)
+		})
+	}
+}

internal/cmd/helpers_test.go

@@ -0,0 +1,75 @@
+package cmd
+
+import (
+	"bufio"
+	"os"
+	"testing"
+
+	v1 "github.com/authzed/authzed-go/proto/authzed/api/v1"
+	"github.com/authzed/spicedb/pkg/tuple"
+	"github.com/samber/lo"
+	"github.com/spf13/cobra"
+	"github.com/stretchr/testify/require"
+
+	"github.com/authzed/zed/pkg/backupformat"
+)
+
+func mapRelationshipTuplesToCLIOutput(t *testing.T, input []string) []string {
+	t.Helper()
+
+	return lo.Map[string, string](input, func(item string, _ int) string {
+		return replaceRelString(item)
+	})
+}
+
+func readLines(t *testing.T, fileName string) []string {
+	t.Helper()
+
+	f, err := os.Open(fileName)
+	require.NoError(t, err)
+	defer func() {
+		_ = f.Close()
+	}()
+
+	var lines []string
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	return lines
+}
+
+func createTestCobraCommandWithFlagValue(t *testing.T, flagName, flagValue string) *cobra.Command {
+	t.Helper()
+
+	c := cobra.Command{}
+	c.Flags().String(flagName, flagValue, "")
+
+	return &c
+}
+
+func createTestBackup(t *testing.T, schema string, relationships []string) string {
+	t.Helper()
+
+	f, err := os.CreateTemp("", "test-backup")
+	require.NoError(t, err)
+	defer f.Close()
+	t.Cleanup(func() {
+		_ = os.Remove(f.Name())
+	})
+
+	avroWriter, err := backupformat.NewEncoder(f, schema, &v1.ZedToken{Token: "test"})
+	require.NoError(t, err)
+	defer func() {
+		require.NoError(t, avroWriter.Close())
+	}()
+
+	for _, rel := range relationships {
+		r := tuple.ParseRel(rel)
+		require.NotNil(t, r)
+		require.NoError(t, avroWriter.Append(r))
+	}
+
+	return f.Name()
+}