lib/test: implement method ExtractInput on Data

Given the path to directory `destDir`, create all of the
[test.Data.Input] with key as its file name.

If the input name contains "/", the path before the base name will be
created along with its parent as long as it is under the `destDir`.

For example, given input name "a/b/c.txt", it will create path "a/b/"
inside `destDir` first, followed by file "c.txt" inside that path.

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/test/data.go b/lib/test/data.go
index 281de010..d113e87c 100644
--- a/lib/test/data.go
+++ b/lib/test/data.go
@@ -207,6 +207,46 @@ func newData(name string) (data *Data) {
 	return data
 }
 
+// ExtractInput given the path to directory `destDir`, create all of the
+// [test.Data.Input] with key as its file name.
+//
+// If the input name contains "/", the path before the base name will be
+// created along with its parent as long as it is under the `destDir`.
+//
+// For example, given input name "a/b/c.txt", it will create path "a/b/"
+// inside `destDir` first, followed by file "c.txt" inside that path.
+func (data *Data) ExtractInput(destDir string) (err error) {
+	var (
+		logp    = `ExtractInput`
+		name    string
+		dir     string
+		base    string
+		path    string
+		content []byte
+	)
+	for name, content = range data.Input {
+		dir = filepath.Dir(name)
+		base = filepath.Base(name)
+		path = filepath.Join(destDir, dir)
+
+		if strings.HasPrefix(path, destDir) && dir != `.` && dir != `/` {
+			err = os.MkdirAll(path, 0700)
+			if err != nil {
+				return fmt.Errorf(`%s: %w`, logp, err)
+			}
+			path = filepath.Join(path, base)
+		} else {
+			path = filepath.Join(destDir, base)
+		}
+
+		err = os.WriteFile(path, content, 0600)
+		if err != nil {
+			return fmt.Errorf(`%s: %w`, logp, err)
+		}
+	}
+	return nil
+}
+
 func (data *Data) parse(content []byte) (err error) {
 	const (
 		stateFlag int = iota