feat: Adding simple sample instrumentation test for ShopViewModel (#151)

Author: markvdouw

core-sdk-samples/higgs-shop-sample-app/app/build.gradle.kts

@@ -117,6 +117,9 @@ dependencies {
     androidTestImplementation("androidx.test:runner:1.4.0")
     androidTestImplementation("com.google.truth:truth:1.1.3")
     androidTestImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.6.4")
+    androidTestImplementation("androidx.arch.core:core-testing:2.1.0")
+    androidTestImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.6.4")
+    androidTestImplementation("org.mockito.kotlin:mockito-kotlin:4.0.0")
 
     androidTestUtil("androidx.test:orchestrator:1.4.1")
 }

core-sdk-samples/higgs-shop-sample-app/app/src/androidTest/kotlin/com/mparticle/example/higgsshopsampleapp/ExampleInstrumentedTests.kt

@@ -0,0 +1,18 @@
+package com.mparticle.example.higgsshopsampleapp
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
+
+/**
+ * Get value from LiveData using suspend coroutine
+ */
+suspend fun <T> LiveData<T?>.getValueFromLiveData() = suspendCoroutine<T?> {
+    var observer: Observer<T?>? = null
+    observer = Observer<T?> { t ->
+        observer?.let { this.removeObserver(it) }
+        it.resume(t)
+    }
+    this.observeForever(observer)
+}

core-sdk-samples/higgs-shop-sample-app/app/src/androidTest/kotlin/com/mparticle/example/higgsshopsampleapp/TestExtFunctions.kt

@@ -0,0 +1,55 @@
+package com.mparticle.example.higgsshopsampleapp
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.internal.runner.junit4.AndroidJUnit4ClassRunner
+import com.mparticle.example.higgsshopsampleapp.repositories.CartRepository
+import com.mparticle.example.higgsshopsampleapp.repositories.ProductsRepository
+import com.mparticle.example.higgsshopsampleapp.viewmodels.ShopViewModel
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.*
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4ClassRunner::class)
+class TestShopViewModel {
+
+    @get:Rule
+    val instantExecutorRule = InstantTaskExecutorRule()
+    private val dispatcher = StandardTestDispatcher()
+
+    private val productsRepository = ProductsRepository()
+    private val cartRepository = CartRepository()
+    private val viewModel =  ShopViewModel()
+
+    @Before
+    fun setup() {
+            Dispatchers.setMain(dispatcher)
+    }
+
+    @After
+    fun tearDown() {
+            Dispatchers.resetMain()
+    }
+
+    @Test
+    fun `testGetProducts`() = runTest {
+        val products = productsRepository.getProducts(ApplicationProvider.getApplicationContext())
+        viewModel.getProducts(ApplicationProvider.getApplicationContext())
+        Assert.assertEquals(products, viewModel.inventoryResponseLiveData.getValueFromLiveData())
+    }
+
+    @Test
+    fun `testGetTotalCartItems`() = runTest {
+        val cartItems = cartRepository.getCartItems(ApplicationProvider.getApplicationContext())
+        viewModel.getTotalCartItems(ApplicationProvider.getApplicationContext())
+        Assert.assertEquals(
+            cartItems.sumOf { it.quantity },
+            viewModel.cartTotalSizeResponseLiveData.getValueFromLiveData()
+        )
+    }
+
+}