Add test for UntarBundle

fsutil/filesystem_test.go

@@ -1,11 +1,96 @@
 package fsutil
 
 import (
+	"archive/tar"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
+func TestUntarBundle(t *testing.T) {
+	t.Parallel()
+
+	// Create tarball contents
+	originalDir := t.TempDir()
+	topLevelFile := filepath.Join(originalDir, "testfile.txt")
+	require.NoError(t, os.WriteFile(topLevelFile, []byte("test1"), 0655))
+	internalDir := filepath.Join(originalDir, "some", "path", "to")
+	require.NoError(t, os.MkdirAll(internalDir, 0755))
+	nestedFile := filepath.Join(internalDir, "anotherfile.txt")
+	require.NoError(t, os.WriteFile(nestedFile, []byte("test2"), 0755))
+
+	// Create test tarball
+	tarballDir := t.TempDir()
+	tarballFile := filepath.Join(tarballDir, "test.gz")
+	createTar(t, tarballFile, originalDir)
+
+	// Confirm we can untar the tarball successfully
+	newDir := t.TempDir()
+	require.NoError(t, UntarBundle(filepath.Join(newDir, "anything"), tarballFile))
+
+	// Confirm the tarball has the contents we expect
+	require.FileExists(t, filepath.Join(newDir, filepath.Base(topLevelFile)))
+	require.FileExists(t, filepath.Join(newDir, "some", "path", "to", filepath.Base(nestedFile)))
+}
+
+// createTar is a helper to create a test tar
+func createTar(t *testing.T, createLocation string, sourceDir string) {
+	tarballFile, err := os.Create(createLocation)
+	require.NoError(t, err)
+	defer tarballFile.Close()
+
+	gzw := gzip.NewWriter(tarballFile)
+	defer gzw.Close()
+
+	tw := tar.NewWriter(gzw)
+	defer tw.Close()
+
+	require.NoError(t, filepath.Walk(sourceDir, func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		srcInfo, err := os.Lstat(path)
+		if os.IsNotExist(err) {
+			return fmt.Errorf("error adding %s to tarball: %w", path, err)
+		}
+
+		hdr, err := tar.FileInfoHeader(srcInfo, path)
+		if err != nil {
+			return fmt.Errorf("error creating tar header: %w", err)
+		}
+		hdr.Name = strings.TrimPrefix(path, sourceDir+"/")
+
+		if err := tw.WriteHeader(hdr); err != nil {
+			return fmt.Errorf("error writing tar header: %w", err)
+		}
+
+		if !srcInfo.Mode().IsRegular() {
+			// Don't open/copy over directories
+			return nil
+		}
+
+		srcFile, err := os.Open(path)
+		if err != nil {
+			return fmt.Errorf("error opening file to add to tarball: %w", err)
+		}
+		defer srcFile.Close()
+
+		if _, err := io.Copy(tw, srcFile); err != nil {
+			return fmt.Errorf("error copying file %s to tarball: %w", path, err)
+		}
+
+		return nil
+	}))
+}
+
 func TestSanitizeExtractPath(t *testing.T) {
 	t.Parallel()