review fixes

packages/in_app_purchase/example/android/app/src/test/java/io/flutter/plugins/inapppurchase/TranslatorTest.java

@@ -159,7 +159,7 @@ public void fromBillingResult() throws JSONException {
   }
 
   @Test
-  public void fromBillingResult_dubugMessageNull() throws JSONException {
+  public void fromBillingResult_debugMessageNull() throws JSONException {
     BillingResult newBillingResult =
         BillingResult.newBuilder().setResponseCode(BillingClient.BillingResponseCode.OK).build();
     Map<String, Object> billingResultMap = Translator.fromBillingResult(newBillingResult);

packages/in_app_purchase/lib/src/billing_client_wrappers/enum_converters.dart

@@ -9,8 +9,9 @@ import 'package:json_annotation/json_annotation.dart';
 part 'enum_converters.g.dart';
 
 /// Serializer for [BillingResponse].
-// Use these in `@JsonSerializable()` classes by annotating them with
-// `@BillingResponseConverter()`.
+///
+/// Use these in `@JsonSerializable()` classes by annotating them with
+/// `@BillingResponseConverter()`.
 class BillingResponseConverter implements JsonConverter<BillingResponse, int> {
   const BillingResponseConverter();
 
@@ -23,8 +24,9 @@ class BillingResponseConverter implements JsonConverter<BillingResponse, int> {
 }
 
 /// Serializer for [SkuType].
-// Use these in `@JsonSerializable()` classes by annotating them with
-// `@SkuTypeConverter()`.
+///
+/// Use these in `@JsonSerializable()` classes by annotating them with
+/// `@SkuTypeConverter()`.
 class SkuTypeConverter implements JsonConverter<SkuType, String> {
   const SkuTypeConverter();
 
@@ -45,8 +47,9 @@ class _SerializedEnums {
 }
 
 /// Serializer for [PurchaseStateWrapper].
-// Use these in `@JsonSerializable()` classes by annotating them with
-// `@PurchaseStateConverter()`.
+///
+/// Use these in `@JsonSerializable()` classes by annotating them with
+/// `@PurchaseStateConverter()`.
 class PurchaseStateConverter
     implements JsonConverter<PurchaseStateWrapper, int> {
   const PurchaseStateConverter();

packages/in_app_purchase/lib/src/in_app_purchase/google_play_connection.dart

@@ -259,7 +259,7 @@ class GooglePlayConnection
       return _maybeAutoConsumePurchase(
           PurchaseDetails.fromPurchase(purchase)..error = error);
     }).toList();
-    if (!purchases.isEmpty) {
+    if (purchases.isNotEmpty) {
       return Future.wait(purchases);
     } else {
       return [

packages/in_app_purchase/lib/src/in_app_purchase/in_app_purchase_connection.dart

@@ -185,7 +185,7 @@ abstract class InAppPurchaseConnection {
   /// If the result indicates other errors, there might be some issue with
   /// the app's code. The developer is responsible to fix the issue.
   ///
-  /// Warning!Failure to call this method and get a successful response within 3 days of the purchase will result a refund on Android.
+  /// Warning! Failure to call this method and get a successful response within 3 days of the purchase will result a refund on Android.
   /// The [consumePurchase] acts as an implicit [completePurchase] on Android.
   ///
   /// The optional parameter `developerPayload` only works on Android.

packages/in_app_purchase/lib/src/in_app_purchase/purchase_details.dart

@@ -175,8 +175,8 @@ class PurchaseDetails {
     @required this.productID,
     @required this.verificationData,
     @required this.transactionDate,
-    this.skPaymentTransaction = null,
-    this.billingClientPurchase = null,
+    this.skPaymentTransaction,
+    this.billingClientPurchase,
   });
 
   /// Generate a [PurchaseDetails] object based on an iOS [SKTransactionWrapper] object.
@@ -194,9 +194,8 @@ class PurchaseDetails {
         this.skPaymentTransaction = transaction,
         this.billingClientPurchase = null,
         _status = SKTransactionStatusConverter()
-            .toPurchaseStatus(transaction.transactionState) {
-    _platform = _kPlatformIOS;
-  }
+            .toPurchaseStatus(transaction.transactionState),
+        _platform = _kPlatformIOS;
 
   /// Generate a [PurchaseDetails] object based on an Android [Purchase] object.
   PurchaseDetails.fromPurchase(PurchaseWrapper purchase)
@@ -210,9 +209,8 @@ class PurchaseDetails {
         this.skPaymentTransaction = null,
         this.billingClientPurchase = purchase,
         _status =
-            PurchaseStateConverter().toPurchaseStatus(purchase.purchaseState) {
-    _platform = _kPlatformAndroid;
-  }
+            PurchaseStateConverter().toPurchaseStatus(purchase.purchaseState),
+        _platform = _kPlatformAndroid;
 }
 
 /// The response object for fetching the past purchases.