From 09d047a868088ea173915ced030ef6c6e5b08f03 Mon Sep 17 00:00:00 2001
From: Simon Binder <simolus3@gmail.com>
Date: Sun, 10 Mar 2019 12:38:53 +0100
Subject: [PATCH] Tests for transactions

---
 README.md                          |  2 +-
 moor/lib/src/runtime/database.dart |  3 ++-
 moor/test/data/utils/mocks.dart    | 23 ++++++++++++++++
 moor/test/transactions_test.dart   | 42 ++++++++++++++++++++++++++++++
 moor_flutter/README.md             |  2 +-
 5 files changed, 69 insertions(+), 3 deletions(-)
 create mode 100644 moor/test/transactions_test.dart

diff --git a/README.md b/README.md
index 55970577..c736fd12 100644
--- a/README.md
+++ b/README.md
@@ -319,8 +319,8 @@ supporting floating / fixed point numbers as well would be awesome
   - Validation
 - Table joins
 - Bulk inserts
-- Transactions
 - Custom column constraints
+- When inserts / updates fail, explain why that happened
 ### Interesting stuff that would be nice to have
 Implementing this will very likely result in backwards-incompatible changes.
 
diff --git a/moor/lib/src/runtime/database.dart b/moor/lib/src/runtime/database.dart
index d4dc85ec..951b8289 100644
--- a/moor/lib/src/runtime/database.dart
+++ b/moor/lib/src/runtime/database.dart
@@ -206,10 +206,11 @@ abstract class GeneratedDatabase extends DatabaseConnectionUser
   ///     [action] function.
   Future transaction(Future Function(QueryEngine transaction) action) async {
     final transaction = Transaction(this, executor.beginTransaction());
+
     try {
       await action(transaction);
     } finally {
-      await transaction?.complete();
+      await transaction.complete();
     }
   }
 }
diff --git a/moor/test/data/utils/mocks.dart b/moor/test/data/utils/mocks.dart
index c389a153..4043c10b 100644
--- a/moor/test/data/utils/mocks.dart
+++ b/moor/test/data/utils/mocks.dart
@@ -9,6 +9,9 @@ export 'package:mockito/mockito.dart';
 typedef Future<T> _EnsureOpenAction<T>(QueryExecutor e);
 
 class MockExecutor extends Mock implements QueryExecutor {
+
+  final MockTransactionExecutor transactions = MockTransactionExecutor();
+
   MockExecutor() {
     when(runSelect(any, any)).thenAnswer((_) => Future.value([]));
     when(runUpdate(any, any)).thenAnswer((_) => Future.value(0));
@@ -19,9 +22,29 @@ class MockExecutor extends Mock implements QueryExecutor {
 
       return action(this);
     });
+
+    when(beginTransaction()).thenAnswer((_) => transactions);
   }
 }
 
+class MockTransactionExecutor extends Mock implements TransactionExecutor {
+
+  MockTransactionExecutor() {
+    when(runSelect(any, any)).thenAnswer((_) => Future.value([]));
+    when(runUpdate(any, any)).thenAnswer((_) => Future.value(0));
+    when(runDelete(any, any)).thenAnswer((_) => Future.value(0));
+    when(runInsert(any, any)).thenAnswer((_) => Future.value(0));
+    when(doWhenOpened(any)).thenAnswer((i) {
+      final action = i.positionalArguments.single as _EnsureOpenAction;
+
+      return action(this);
+    });
+
+    when(send()).thenAnswer((_) => Future.value(null));
+  }
+
+}
+
 class MockStreamQueries extends Mock implements StreamQueryStore {}
 
 // used so that we can mock the SqlExecutor typedef
diff --git a/moor/test/transactions_test.dart b/moor/test/transactions_test.dart
new file mode 100644
index 00000000..41997889
--- /dev/null
+++ b/moor/test/transactions_test.dart
@@ -0,0 +1,42 @@
+import 'package:test_api/test_api.dart';
+
+import 'data/tables/todos.dart';
+import 'data/utils/mocks.dart';
+
+void main() {
+  TodoDb db;
+  MockExecutor executor;
+  MockStreamQueries streamQueries;
+
+  setUp(() {
+    executor = MockExecutor();
+    streamQueries = MockStreamQueries();
+    db = TodoDb(executor)..streamQueries = streamQueries;
+  });
+
+  test("transactions don't allow creating streams", () {
+    expect(() async {
+      await db.transaction((t) {
+        t.select(db.users).watch();
+      });
+    }, throwsStateError);
+
+    verify(executor.transactions.send());
+  });
+
+  test('transactions notify about table udpates after completing', () async {
+    when(executor.transactions.runUpdate(any, any)).thenAnswer((_) => Future.value(2));
+
+    await db.transaction((t) async {
+      await t.update(db.users).write(User(name: 'Updated name'));
+
+      // Even though we just wrote to users, this only happened inside the
+      // transaction, so the top level stream queries should not be updated.
+      verifyNever(streamQueries.handleTableUpdates(any));
+    });
+
+    // After the transaction completes, the queries should be updated
+    verify(streamQueries.handleTableUpdates({'users'}));
+    verify(executor.transactions.send());
+  });
+}
\ No newline at end of file
diff --git a/moor_flutter/README.md b/moor_flutter/README.md
index 55970577..c736fd12 100644
--- a/moor_flutter/README.md
+++ b/moor_flutter/README.md
@@ -319,8 +319,8 @@ supporting floating / fixed point numbers as well would be awesome
   - Validation
 - Table joins
 - Bulk inserts
-- Transactions
 - Custom column constraints
+- When inserts / updates fail, explain why that happened
 ### Interesting stuff that would be nice to have
 Implementing this will very likely result in backwards-incompatible changes.