TestingUsingPublicAPI.kt

@Test
fun `refer friend with new referral verify referral successful`() {
   val friendReferral = getInstance()
   friendReferral.referFriend("testUserId", getStaleReferral())
   assertThat(referralList.contains("testUserId")).isTrue()
}

@Test
fun `refer friend with stale referral verify referral failue`() {
   val friendReferral = getInstance()
   friendReferral.referFriend("testUserId", getStaleReferral())
   assertThat(referralList.contains("testUserId")).isFalse()
}