fix: Adds default path for data flag

Add default value as 'data' for the data flag. Updated data loading function to not throw an error if it is using the default data path and it is missing.

Fixes open-policy-agent#800

internal/commands/test.go

@@ -183,7 +183,7 @@ func NewTestCommand(ctx context.Context) *cobra.Command {
 	cmd.Flags().StringSliceP("policy", "p", []string{"policy"}, "Path to the Rego policy files directory")
 	cmd.Flags().StringSliceP("update", "u", []string{}, "A list of URLs can be provided to the update flag, which will download before the tests run")
 	cmd.Flags().StringSliceP("namespace", "n", []string{"main"}, "Test policies in a specific namespace")
-	cmd.Flags().StringSliceP("data", "d", []string{}, "A list of paths from which data for the rego policies will be recursively loaded")
+	cmd.Flags().StringSliceP("data", "d", []string{"data"}, "A list of paths from which data for the rego policies will be recursively loaded")
 
 	cmd.Flags().StringSlice("proto-file-dirs", []string{}, "A list of directories containing Protocol Buffer definitions")
 	cmd.Flags().Bool("tls", true, "Use TLS to access the registry")

policy/engine.go

@@ -3,7 +3,9 @@ package policy
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -131,7 +133,11 @@ func LoadWithData(policyPaths []string, dataPaths []string, capabilities string,
 		return !contains([]string{".yaml", ".yml", ".json"}, filepath.Ext(info.Name()))
 	})
 	if err != nil {
-		return nil, fmt.Errorf("filter data paths: %w", err)
+		if errors.Is(err.(loader.Errors)[0], fs.ErrNotExist) && len(dataPaths) == 1 && dataPaths[0] == "data" {
+			allDocumentPaths = []string{}
+		} else {
+			return nil, fmt.Errorf("sldkjf filter data paths: %s", err)
+		}
 	}
 
 	documents, err := loader.NewFileLoader().All(allDocumentPaths)