[in_app_purchase] Created first unit tests on Android for IAP

packages/in_app_purchase/android/build.gradle

@@ -37,7 +37,7 @@ dependencies {
     implementation 'androidx.annotation:annotation:1.0.0'
     implementation 'com.android.billingclient:billing:3.0.2'
     testImplementation 'junit:junit:4.12'
-    testImplementation 'org.mockito:mockito-core:3.6.0'
+    testImplementation 'org.mockito:mockito-inline:3.6.0'
     androidTestImplementation 'androidx.test:runner:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
 }

packages/in_app_purchase/android/src/main/java/io/flutter/plugins/inapppurchase/MethodCallHandlerImpl.java

@@ -15,6 +15,7 @@
 import android.util.Log;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 import com.android.billingclient.api.AcknowledgePurchaseParams;
 import com.android.billingclient.api.AcknowledgePurchaseResponseListener;
 import com.android.billingclient.api.BillingClient;
@@ -43,14 +44,14 @@ class MethodCallHandlerImpl
   private static final String LOAD_SKU_DOC_URL =
       "https://github.com/flutter/plugins/blob/master/packages/in_app_purchase/README.md#loading-products-for-sale";
 
-  @Nullable private BillingClient billingClient;
+  @VisibleForTesting @Nullable BillingClient billingClient;
   private final BillingClientFactory billingClientFactory;
 
   @Nullable private Activity activity;
   private final Context applicationContext;
   private final MethodChannel methodChannel;
 
-  private HashMap<String, SkuDetails> cachedSkus = new HashMap<>();
+  @VisibleForTesting HashMap<String, SkuDetails> cachedSkus = new HashMap<>();
 
   /** Constructs the MethodCallHandlerImpl */
   MethodCallHandlerImpl(

packages/in_app_purchase/android/src/test/java/io/flutter/plugins/inapppurchase/MethodCallHandlerTest.java

@@ -0,0 +1,198 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.inapppurchase;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.Activity;
+import android.content.Context;
+import com.android.billingclient.api.BillingClient;
+import com.android.billingclient.api.BillingFlowParams;
+import com.android.billingclient.api.BillingResult;
+import com.android.billingclient.api.SkuDetails;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+import java.util.HashMap;
+import java.util.Map;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.MockedStatic;
+
+public class MethodCallHandlerTest {
+  private MethodCallHandlerImpl methodCallHandler;
+  private MockedStatic<BillingFlowParams> mockStaticBuilder;
+  private BillingFlowParams.Builder billingFlowParamsBuilder;
+  private BillingFlowParams billingFlowParams;
+
+  @Before
+  public void before() {
+    methodCallHandler =
+        new MethodCallHandlerImpl(
+            null, mock(Context.class), mock(MethodChannel.class), mock(BillingClientFactory.class));
+    methodCallHandler.billingClient = mock(BillingClient.class);
+    BillingClient client = mock(BillingClient.class);
+    when(client.isReady()).thenReturn(true);
+
+    SkuDetails details = mock(SkuDetails.class);
+    methodCallHandler.cachedSkus.put("testPurchase", details);
+
+    setupBillingFlow();
+  }
+
+  @After
+  public void after() {
+    closeBillingFlow();
+  }
+
+  @Test
+  public void isReady_returns_true_if_billingClientIsReady() {
+    BillingClient client = mock(BillingClient.class);
+    when(client.isReady()).thenReturn(true);
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+    MethodCall call = new MethodCall(InAppPurchasePlugin.MethodNames.IS_READY, null);
+
+    methodCallHandler.billingClient = client;
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(result, times(1)).success(true);
+  }
+
+  @Test
+  public void isReady_returns_false_if_billingClientIsNotReady() {
+    BillingClient client = mock(BillingClient.class);
+    when(client.isReady()).thenReturn(false);
+    MethodCall call = new MethodCall(InAppPurchasePlugin.MethodNames.IS_READY, null);
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    methodCallHandler.billingClient = client;
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(result, times(1)).success(false);
+  }
+
+  @Test
+  public void isReady_returns_false_if_billingClientIsNotSet() {
+    MethodCall call = new MethodCall(InAppPurchasePlugin.MethodNames.IS_READY, null);
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    methodCallHandler.billingClient = null;
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(result, times(1))
+        .error("UNAVAILABLE", "BillingClient is unset. Try reconnecting.", null);
+  }
+
+  private Map<String, Object> createBillingArgs() {
+    Map<String, Object> args = new HashMap<>();
+    args.put("sku", "testPurchase");
+    return args;
+  }
+
+  @Test
+  public void launchBillingFlow_fails_withMissingSku() {
+    MethodCall call =
+        new MethodCall(InAppPurchasePlugin.MethodNames.LAUNCH_BILLING_FLOW, createBillingArgs());
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    methodCallHandler.cachedSkus.remove("testPurchase");
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(result, times(1))
+        .error(
+            "NOT_FOUND",
+            "Details for sku testPurchase are not available. "
+                + "It might because skus were not fetched prior to the call. "
+                + "Please fetch the skus first. An example of how to fetch the skus could be found here: "
+                + "https://github.com/flutter/plugins/blob/master/packages/in_app_purchase/README.md#loading-products-for-sale",
+            null);
+  }
+
+  @Test
+  public void launchBillingFlow_fails_whenNotAttachedToActivity() {
+    MethodCall call =
+        new MethodCall(InAppPurchasePlugin.MethodNames.LAUNCH_BILLING_FLOW, createBillingArgs());
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(result, times(1))
+        .error(
+            "ACTIVITY_UNAVAILABLE",
+            "Details for sku testPurchase are not available. This method must be run with the app in foreground.",
+            null);
+  }
+
+  @Test
+  public void launchBillingFlow_launchesBillingFlowOnClient() {
+    MethodCall call =
+        new MethodCall(InAppPurchasePlugin.MethodNames.LAUNCH_BILLING_FLOW, createBillingArgs());
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    assert methodCallHandler.billingClient != null;
+    when(methodCallHandler.billingClient.launchBillingFlow(
+            any(Activity.class), any(BillingFlowParams.class)))
+        .thenReturn(mock(BillingResult.class));
+
+    Activity activity = mock(Activity.class);
+    methodCallHandler.setActivity(activity);
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(methodCallHandler.billingClient, times(1))
+        .launchBillingFlow(activity, billingFlowParams);
+    verify(result, times(1)).success(any());
+  }
+
+  @Test
+  public void launchBillingFlow_setsObfuscatedProfileId() {
+    String obfuscatedProfileId = "abcdef";
+    Map<String, Object> billingArgs = createBillingArgs();
+    billingArgs.put("obfuscatedProfileId", obfuscatedProfileId);
+
+    MethodCall call =
+        new MethodCall(InAppPurchasePlugin.MethodNames.LAUNCH_BILLING_FLOW, billingArgs);
+    MethodChannel.Result result = mock(MethodChannel.Result.class);
+
+    methodCallHandler.setActivity(mock(Activity.class));
+    methodCallHandler.onMethodCall(call, result);
+
+    verify(billingFlowParamsBuilder, times(1)).setObfuscatedProfileId(obfuscatedProfileId);
+  }
+
+  private void setupBillingFlow() {
+    assert methodCallHandler.billingClient != null;
+    when(methodCallHandler.billingClient.launchBillingFlow(
+            any(Activity.class), any(BillingFlowParams.class)))
+        .thenReturn(mock(BillingResult.class));
+
+    billingFlowParamsBuilder = mock(BillingFlowParams.Builder.class);
+    mockStaticBuilder = mockStatic(BillingFlowParams.class);
+    mockStaticBuilder
+        .when(
+            new MockedStatic.Verification() {
+              @Override
+              public void apply() {
+                BillingFlowParams.newBuilder();
+              }
+            })
+        .thenReturn(billingFlowParamsBuilder);
+
+    when(billingFlowParamsBuilder.setSkuDetails(any(SkuDetails.class)))
+        .thenReturn(billingFlowParamsBuilder);
+    when(billingFlowParamsBuilder.setObfuscatedAccountId(any(String.class)))
+        .thenReturn(billingFlowParamsBuilder);
+    billingFlowParams = mock(BillingFlowParams.class);
+    when(billingFlowParamsBuilder.build()).thenReturn(billingFlowParams);
+  }
+
+  private void closeBillingFlow() {
+    mockStaticBuilder.close();
+  }
+}