test: rescan libraries to clear them beforehand

Author: Luca Bianconi

arduino/libraries/librariesmanager/librariesmanager_test.go

@@ -0,0 +1,18 @@
+package librariesmanager
+
+import (
+	"testing"
+
+	"github.com/arduino/arduino-cli/arduino/libraries"
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_RescanLibrariesCallClear(t *testing.T) {
+	baseDir := paths.New(t.TempDir())
+	lm := NewLibraryManager(baseDir.Join("index_dir"), baseDir.Join("downloads_dir"))
+	lm.Libraries["testLibA"] = libraries.List{}
+	lm.Libraries["testLibB"] = libraries.List{}
+	lm.RescanLibraries()
+	require.Len(t, lm.Libraries, 0)
+}