Add temp dir unit test

Author: MatteoPologruto

updater/download_image_test.go

@@ -0,0 +1,28 @@
+package updater
+
+import (
+	"os"
+	"testing"
+
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTempDir(t *testing.T) {
+	userCacheDir, err := os.UserCacheDir()
+	require.NoError(t, err)
+
+	defaultTempDir, err := SetTempDir("download-", "")
+	defer defaultTempDir.RemoveAll()
+	require.NoError(t, err)
+	require.DirExists(t, defaultTempDir.String())
+	require.Contains(t, defaultTempDir.Base(), "download-")
+	require.Contains(t, defaultTempDir.String(), userCacheDir)
+
+	customTempDir, err := SetTempDir("extract-", ".")
+	defer customTempDir.RemoveAll()
+	require.NoError(t, err)
+	require.DirExists(t, customTempDir.String())
+	require.Contains(t, customTempDir.Base(), "extract-")
+	require.Contains(t, customTempDir.String(), paths.New(".").String())
+}