Only save eventId in MessageContentModel

Turns out trying to manage pointers in the model is a bad idea so only save eventId in MessageContentModel, events pointers will now only be obtained temporarily then discarded to avoid both creating additional copies of the event in the model and potential sources of crashes.

This also creates a basic unit test that we can add to going forward.

autotests/messagecontentmodeltest.cpp

@@ -0,0 +1,61 @@
+// SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#include <QObject>
+#include <QSignalSpy>
+#include <QTest>
+
+#include <Quotient/connection.h>
+#include <Quotient/quotient_common.h>
+#include <Quotient/roommember.h>
+#include <Quotient/syncdata.h>
+
+#include "models/messagecontentmodel.h"
+
+#include "testutils.h"
+
+using namespace Quotient;
+using namespace Qt::Literals::StringLiterals;
+
+class MessageContentModelTest : public QObject
+{
+    Q_OBJECT
+
+private:
+    Connection *connection = nullptr;
+
+private Q_SLOTS:
+    void initTestCase();
+
+    void missingEvent();
+};
+
+void MessageContentModelTest::initTestCase()
+{
+    connection = Connection::makeMockConnection(QStringLiteral("@bob:kde.org"));
+}
+
+void MessageContentModelTest::missingEvent()
+{
+    auto room = new TestUtils::TestRoom(connection, QStringLiteral("#firstRoom:kde.org"));
+    auto model1 = MessageContentModel(room, "$153456789:example.org"_L1);
+
+    QCOMPARE(model1.rowCount(), 1);
+    QCOMPARE(model1.data(model1.index(0), MessageContentModel::ComponentTypeRole), MessageComponentType::Loading);
+    QCOMPARE(model1.data(model1.index(0), MessageContentModel::DisplayRole), "Loading"_L1);
+
+    auto model2 = MessageContentModel(room, "$153456789:example.org"_L1, true);
+
+    QCOMPARE(model2.rowCount(), 1);
+    QCOMPARE(model2.data(model2.index(0), MessageContentModel::ComponentTypeRole), MessageComponentType::Loading);
+    QCOMPARE(model2.data(model2.index(0), MessageContentModel::DisplayRole), "Loading reply"_L1);
+
+    room->syncNewEvents(QLatin1String("test-min-sync.json"));
+    QCOMPARE(model1.rowCount(), 2);
+    QCOMPARE(model1.data(model1.index(0), MessageContentModel::ComponentTypeRole), MessageComponentType::Author);
+    QCOMPARE(model1.data(model1.index(1), MessageContentModel::ComponentTypeRole), MessageComponentType::Text);
+    QCOMPARE(model1.data(model1.index(1), MessageContentModel::DisplayRole), u"<b>This is an example<br>text message</b>"_s);
+}
+
+QTEST_MAIN(MessageContentModelTest)
+#include "messagecontentmodeltest.moc"