yaotp/app/src/test/java/com/chameth/yaotp/viewmodel/OtpListViewModelTest.kt

package com.chameth.yaotp.viewmodel

import androidx.arch.core.executor.testing.InstantTaskExecutorRule
import com.chameth.yaotp.accounts.Account
import com.nhaarman.mockitokotlin2.*
import org.junit.Assert.assertEquals
import org.junit.Rule
import org.junit.Test

class OtpListViewModelTest {

    @get:Rule
    val instantTaskExecutorRule = InstantTaskExecutorRule()

    private val viewModel = OtpListViewModel()
    private val observer = mock<OtpListViewModel.AccountObserver>()

    @Test
    fun testAddAccount_incrementsNumberOfAccounts() {
        assertEquals(0, viewModel.numberOfAccounts)
        viewModel.addAccount(mock())
        assertEquals(1, viewModel.numberOfAccounts)
        viewModel.addAccount(mock())
        assertEquals(2, viewModel.numberOfAccounts)
    }

    @Test
    fun testRemoveAccount_decrementsNumberOfAccounts() {
        val account1 = mock<Account>()
        val account2 = mock<Account>()
        viewModel.addAccount(account1)
        viewModel.addAccount(account2)
        viewModel.removeAccount(account1)
        assertEquals(1, viewModel.numberOfAccounts)
        viewModel.removeAccount(account2)
        assertEquals(0, viewModel.numberOfAccounts)
    }

    @Test
    fun testRemoveAccount_withNonExistantAccount_doesNothing() {
        val account1 = mock<Account>()
        val account2 = mock<Account>()
        viewModel.addAccount(account1)
        viewModel.addObserver(observer)
        viewModel.removeAccount(account2)

        verifyNoMoreInteractions(observer)
    }

    @Test
    fun testAddAccount_notifiesRegisteredObservers() {
        viewModel.addAccount(mock())
        viewModel.addObserver(observer)
        viewModel.addAccount(mock())
        viewModel.removeObserver(observer)
        viewModel.addAccount(mock())

        verify(observer).accountAdded(1)
        verify(observer, never()).accountAdded(0)
        verify(observer, never()).accountAdded(2)
    }

    @Test
    fun testRemoveAccount_notifiesRegisteredObservers() {
        val account1 = mock<Account>()
        val account2 = mock<Account>()
        val account3 = mock<Account>()
        viewModel.addAccount(account1)
        viewModel.addAccount(account2)
        viewModel.addAccount(account3)
        viewModel.removeAccount(account1)
        viewModel.addObserver(observer)
        viewModel.removeAccount(account3)
        viewModel.removeObserver(observer)
        viewModel.removeAccount(account2)

        verify(observer).accountRemoved(1)
        verify(observer, never()).accountRemoved(0)
    }

    @Test
    fun testGetViewModel_returnsCorrectViewModel() {
        viewModel.addAccount(mock { on { label } doReturn "Foo" })
        viewModel.addAccount(mock { on { label } doReturn "Bar" })

        assertEquals("Foo", viewModel.getViewModelForAccount(0).label.value)
        assertEquals("Bar", viewModel.getViewModelForAccount(1).label.value)
    }

}