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, 69 insertions, 0 deletions

diff --git a/lib/test/data_example_test.go b/lib/test/data_example_test.go
new file mode 100644
index 00000000..b544dacd
--- /dev/null
+++ b/lib/test/data_example_test.go
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
+
+package test_test
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+
+	"git.sr.ht/~shulhan/pakakeh.go/lib/test"
+)
+
+func ExampleData_ExtractInput() {
+	var tempDir string
+	var err error
+	tempDir, err = os.MkdirTemp(``, ``)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	var data = &test.Data{
+		Input: map[string][]byte{
+			`dir/a.txt`:       []byte(`Content of dir/a.txt.`),
+			`dir/sub/b.txt`:   []byte(`Content of dir/sub/b.txt.`),
+			`c.txt`:           []byte(`Content of c.txt.`),
+			`dir/../../d.txt`: []byte(`Content of d.txt.`),
+		},
+	}
+
+	// The ExtractInput will create the following directory structures,
+	// including their files,
+	//
+	// ├── c.txt
+	// ├── dir
+	// │   ├── a.txt
+	// │   └── sub
+	// │       └── b.txt
+	// └── d.txt
+	//
+	err = data.ExtractInput(tempDir)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var listExtractedInput = []string{
+		filepath.Join(tempDir, `dir/a.txt`),
+		filepath.Join(tempDir, `dir/sub/b.txt`),
+		filepath.Join(tempDir, `c.txt`),
+		// Since the path of "dir/../../d.txt" is outside of the
+		// tempDir, the file will be created on root of tempDir.
+		filepath.Join(tempDir, `d.txt`),
+	}
+	var got []byte
+	for _, path := range listExtractedInput {
+		got, err = os.ReadFile(path)
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("%s\n", got)
+	}
+	// Output:
+	// Content of dir/a.txt.
+	// Content of dir/sub/b.txt.
+	// Content of c.txt.
+	// Content of d.txt.
+}