Make QPromise::all accept more container types

Currently, QPromise can't be added dynamically to QVector (::push_* | ::append) because it doesn't expose a default constructor. Until deciding if a default constructor should be added (private/public?), let's make the `QPromise::all` method work with any container types that are STL compatible.

tests/auto/qtpromise/qpromise/all/all.pro

@@ -0,0 +1,4 @@
+TARGET = tst_qpromise_all
+SOURCES += $$PWD/tst_all.cpp
+
+include(../../qtpromise.pri)

tests/auto/qtpromise/qpromise/all/tst_all.cpp

@@ -0,0 +1,103 @@
+// Tests
+#include "../../shared/utils.h"
+
+// QtPromise
+#include <QtPromise>
+
+// Qt
+#include <QtTest>
+
+using namespace QtPromise;
+
+class tst_qpromise_all : public QObject
+{
+    Q_OBJECT
+
+private Q_SLOTS:
+    void qList();
+    //void qVector();
+    void stdList();
+    void stdVector();
+};
+
+QTEST_MAIN(tst_qpromise_all)
+#include "tst_all.moc"
+
+namespace {
+
+template <class Sequence>
+struct SequenceTester
+{
+};
+
+template <template <typename, typename...> class Sequence, typename ...Args>
+struct SequenceTester<Sequence<QPromise<int>, Args...> >
+{
+    static void exec()
+    {
+        Sequence<QPromise<int>, Args...> promises{
+            QPromise<int>::resolve(42),
+            QPromise<int>::resolve(43),
+            QPromise<int>::resolve(44)
+        };
+
+        promises.push_back(QPromise<int>::resolve(45));
+        promises.insert(++promises.begin(), QPromise<int>::resolve(46));
+        promises.pop_back();
+
+        auto p = QPromise<int>::all(promises);
+
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<QVector<int> > >::value));
+        QCOMPARE(waitForValue(p, QVector<int>()), QVector<int>({42, 46, 43, 44}));
+    }
+};
+
+template <template <typename, typename...> class Sequence, typename ...Args>
+struct SequenceTester<Sequence<QPromise<void>, Args...> >
+{
+    static void exec()
+    {
+        Sequence<QPromise<void>, Args...> promises{
+            QPromise<void>::resolve(),
+            QPromise<void>::resolve(),
+            QPromise<void>::resolve()
+        };
+
+        promises.push_back(QPromise<void>::resolve());
+        promises.insert(++promises.begin(), QPromise<void>::resolve());
+        promises.pop_back();
+
+        auto p = QPromise<void>::all(promises);
+
+        Q_STATIC_ASSERT((std::is_same<decltype(p), QPromise<void> >::value));
+        QCOMPARE(waitForValue(p, -1, 42), 42);
+    }
+};
+
+} // anonymous namespace
+
+void tst_qpromise_all::qList()
+{
+    SequenceTester<QList<QPromise<int> > >::exec();
+    SequenceTester<QList<QPromise<void> > >::exec();
+}
+
+// QVector::push_back/append isn't supported since it requires a default
+// constructor (see https://github.com/simonbrunel/qtpromise/issues/3)
+//void tst_qpromise_all::qVector()
+//{
+//    SequenceTester<QVector<QPromise<int> > >::exec();
+//    SequenceTester<QVector<QPromise<void> > >::exec();
+//}
+
+void tst_qpromise_all::stdList()
+{
+    SequenceTester<std::list<QPromise<int> > >::exec();
+    SequenceTester<std::list<QPromise<void> > >::exec();
+}
+
+void tst_qpromise_all::stdVector()
+{
+    SequenceTester<std::vector<QPromise<int> > >::exec();
+    SequenceTester<std::vector<QPromise<void> > >::exec();
+}

tests/auto/qtpromise/qpromise/qpromise.pro

@@ -1,5 +1,6 @@
 TEMPLATE = subdirs
 SUBDIRS += \
+    all \
     construct \
     delay \
     fail \