Test added for addNewTask

app/src/test/java/com/example/android/architecture/blueprints/todoapp/tasks/LiveDataTestExtension.kt

@@ -0,0 +1,35 @@
+package com.example.android.architecture.blueprints.todoapp.tasks
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.TimeoutException
+
+fun <T>LiveData<T>.getOrWaitValue(time: Long = 2, timeUnit: TimeUnit = TimeUnit.SECONDS): T {
+
+    var data: T? = null
+    val latch = CountDownLatch(/* count= */ 1)
+
+    val observer = object : Observer<T> {
+
+        override fun onChanged(t: T) {
+            data = t
+            latch.countDown()
+            removeObserver(this)
+        }
+    }
+
+    observeForever(observer)
+
+    try {
+
+        if (!latch.await(time, timeUnit)) {
+            throw TimeoutException("Latch Timeout occurred")
+        }
+    } finally {
+        removeObserver(observer)
+    }
+
+    return data as T
+}

app/src/test/java/com/example/android/architecture/blueprints/todoapp/tasks/TasksViewModelTest.kt

@@ -6,6 +6,7 @@ import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.example.android.architecture.blueprints.todoapp.Event
 import com.google.common.truth.Truth
+import org.junit.Before
 import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -17,25 +18,39 @@ internal class TasksViewModelTest {
     @get:Rule
     val instantExecutorRule = InstantTaskExecutorRule()
 
+    lateinit var tasksViewModel: TasksViewModel
+
+    @Before
+    fun setupBefore() {
+
+        tasksViewModel = TasksViewModel(ApplicationProvider.getApplicationContext())
+    }
+
     @Test
     fun addNewTask_setNewTask() {
 
         // Assign a ViewModel
-        val tasksViewModel = TasksViewModel(ApplicationProvider.getApplicationContext())
-        val observer = Observer<Event<Unit>>{}
+        // Done in setupBefore
 
-        try {
+        // Act new Task is added
+        tasksViewModel.addNewTask()
+
+        // Assert adding a new Task
+        val value = tasksViewModel.newTaskEvent.getOrWaitValue()
+        Truth.assertThat(value.getContentIfNotHandled()).isNotNull()
+    }
+
+    @Test
+    fun setFiltering_toAllTask_taskAddNewVisible() {
 
-            // Act new Task is added
-            tasksViewModel.newTaskEvent.observeForever(observer)
-            tasksViewModel.addNewTask()
+        // Assign
+        // Done in setupBefore
 
-            // Assert adding a new Task
-            val value = tasksViewModel.newTaskEvent.value
-            Truth.assertThat(value?.getContentIfNotHandled()).isNotNull()
+        // Act
+        tasksViewModel.setFiltering(TasksFilterType.ALL_TASKS)
 
-        } finally {
-            tasksViewModel.newTaskEvent.removeObserver(observer)
-        }
+        // Assert
+        val value = tasksViewModel.tasksAddViewVisible.getOrWaitValue()
+        Truth.assertThat(value).isTrue()
     }
 }