Generalize cache get with expire param

datasources/mtr/bus/busschedule_test.go

@@ -0,0 +1,12 @@
+package bus
+
+import (
+	"testing"
+)
+
+func TestGetSchedule(t *testing.T) {
+    _, err := getSchedule( "en", "K66" )
+    if err != nil {
+        t.Error( err )
+    }
+}