Unit test cases for DashboardViewModel

app/src/main/java/in/projecteka/jataayu/ui/dashboard/DashboardPagerAdapter.kt

@@ -7,7 +7,7 @@ import androidx.fragment.app.FragmentActivity
 import androidx.viewpager2.adapter.FragmentStateAdapter
 
 internal class DashboardPagerAdapter(activity: FragmentActivity) : FragmentStateAdapter(activity) {
-    val listOfFragments = arrayListOf<Fragment>(UserAccountsFragment.newInstance(), ConsentHostFragment.newInstance())
+    private val listOfFragments = arrayListOf<Fragment>(UserAccountsFragment.newInstance(), ConsentHostFragment.newInstance())
 
     override fun createFragment(position: Int): Fragment = listOfFragments[position]
 

app/src/test/java/in/projecteka/jataayu/dashboard/DashboardViewModelTest.kt

@@ -0,0 +1,102 @@
+package `in`.projecteka.jataayu.dashboard
+
+import `in`.projecteka.jataayu.R
+import `in`.projecteka.jataayu.ui.dashboard.DashboardViewModel
+import android.view.MenuItem
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.LifecycleRegistry
+import androidx.lifecycle.Observer
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mock
+import org.mockito.Mockito.*
+import org.mockito.MockitoAnnotations
+import org.mockito.junit.MockitoJUnitRunner
+
+@RunWith(MockitoJUnitRunner::class)
+class DashboardViewModelTest {
+
+    @Mock
+    private lateinit var showFragmentObserver: Observer<DashboardViewModel.Show>
+
+    @Mock
+    lateinit var lifecycleOwner: LifecycleOwner
+
+    lateinit var lifecycleRegistry: LifecycleRegistry
+
+    @get:Rule
+    val instantTaskExecutorRule = InstantTaskExecutorRule()
+
+    private var viewModel: DashboardViewModel = DashboardViewModel()
+
+    @Before
+    fun setup() {
+        MockitoAnnotations.initMocks(this)
+        lifecycleRegistry = LifecycleRegistry(lifecycleOwner)
+        `when`(lifecycleOwner.lifecycle).thenReturn(lifecycleRegistry)
+    }
+
+    @Test
+    fun `no event is observed without redirect being called when lifecycle owner is created`() {
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE)
+        viewModel.showFragmentEvent.observe(lifecycleOwner, showFragmentObserver)
+
+        verify(showFragmentObserver, never()).onChanged(any())
+
+    }
+
+    @Test
+    fun `no event is observed when lifecycle owner is destroyed`() {
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_DESTROY)
+        viewModel.showFragmentEvent.observe(lifecycleOwner, showFragmentObserver)
+
+        verify(showFragmentObserver, never()).onChanged(any())
+
+    }
+
+    @Test
+    fun `redirected to home when navigation is clicked to show UserAccounts`(){
+        val menuItem = mock(MenuItem::class.java)
+        `when`(menuItem.itemId).thenReturn(R.id.action_accounts)
+
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_RESUME)
+        viewModel.showFragmentEvent.observe(lifecycleOwner,showFragmentObserver)
+
+        viewModel.onNavigationItemSelected(menuItem)
+
+        verify(showFragmentObserver, times(1)).onChanged(DashboardViewModel.Show.USER_ACCOUNT)
+        verify(showFragmentObserver, never()).onChanged(DashboardViewModel.Show.CONSENT_HOME)
+    }
+
+    @Test
+    fun `redirected to consents when navigation is clicked to show Consents`(){
+        val menuItem = mock(MenuItem::class.java)
+        `when`(menuItem.itemId).thenReturn(R.id.action_consents)
+
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_RESUME)
+        viewModel.showFragmentEvent.observe(lifecycleOwner,showFragmentObserver)
+
+        viewModel.onNavigationItemSelected(menuItem)
+
+        verify(showFragmentObserver, times(1)).onChanged(DashboardViewModel.Show.CONSENT_HOME)
+        verify(showFragmentObserver, never()).onChanged(DashboardViewModel.Show.USER_ACCOUNT)
+    }
+
+    @Test
+    fun `no redirection when neither consent or home is clicked`(){
+        val menuItem = mock(MenuItem::class.java)
+        `when`(menuItem.itemId).thenReturn(R.id.action_settings)
+
+        lifecycleRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE)
+        viewModel.showFragmentEvent.observe(lifecycleOwner,showFragmentObserver)
+
+        viewModel.onNavigationItemSelected(menuItem)
+
+        verify(showFragmentObserver, never()).onChanged(DashboardViewModel.Show.CONSENT_HOME)
+        verify(showFragmentObserver, never()).onChanged(DashboardViewModel.Show.USER_ACCOUNT)
+    }
+}