Move helpers in separate file and add unit tests

Gather helpers in `promisehelpers.h` and add a global include file to make easier integration with the lib (`#include <QtPromise>`).

src/qtpromise/qpromise.h

@@ -104,6 +104,5 @@ private:
 } // namespace QtPromise
 
 #include "qpromise.inl"
-#include "qpromise_qfuture.inl"
 
 #endif // ifndef _QTPROMISE_QPROMISE_H

src/qtpromise/qpromise.inl

@@ -311,37 +311,4 @@ inline void QPromise<void>::notify(const typename QtPromisePrivate::PromiseData<
     });
 }
 
-// Helpers
-
-template <typename T>
-typename QtPromisePrivate::PromiseDeduce<T>::Type qPromise(const T& value)
-{
-    using namespace QtPromisePrivate;
-    using Promise = typename PromiseDeduce<T>::Type;
-    return Promise([=](
-        const QPromiseResolve<typename Promise::Type>& resolve,
-        const QPromiseReject<typename Promise::Type>& reject) {
-        PromiseFulfill<T>::call(value, resolve, reject);
-    });
-}
-
-QPromise<void> qPromise()
-{
-    return QPromise<void>([](
-        const QPromiseResolve<void>& resolve) {
-        resolve();
-    });
-}
-
-template <typename T>
-QPromise<QVector<T> > qPromiseAll(const QVector<QPromise<T> >& promises)
-{
-    return QPromise<T>::all(promises);
-}
-
-QPromise<void> qPromiseAll(const QVector<QPromise<void> >& promises)
-{
-    return QPromise<void>::all(promises);
-}
-
 } // namespace QtPromise

src/qtpromise/qpromise_p.h

@@ -6,7 +6,6 @@
 #include "qpromiseglobal.h"
 
 // Qt
-#include <QCoreApplication>
 #include <QTimer>
 #include <QSharedData>
 #include <QVector>

src/qtpromise/qpromisefuture.h

@@ -1,3 +1,6 @@
+#ifndef _QTPROMISE_QPROMISEFUTURE_P_H
+#define _QTPROMISE_QPROMISEFUTURE_P_H
+
 #include <QFutureWatcher>
 #include <QFuture>
 
@@ -62,3 +65,5 @@ struct PromiseFulfill<QFuture<void> >
 };
 
 } // namespace QtPromise
+
+#endif // _QTPROMISE_QPROMISEFUTURE_P_H

src/qtpromise/qpromisehelpers.h

@@ -0,0 +1,42 @@
+#ifndef _QTPROMISE_QPROMISEHELPERS_H
+#define _QTPROMISE_QPROMISEHELPERS_H
+
+// QtPromise
+#include "qpromise_p.h"
+
+namespace QtPromise {
+
+template <typename T>
+typename QtPromisePrivate::PromiseDeduce<T>::Type qPromise(const T& value)
+{
+    using namespace QtPromisePrivate;
+    using Promise = typename PromiseDeduce<T>::Type;
+    return Promise([=](
+        const QPromiseResolve<typename Promise::Type>& resolve,
+        const QPromiseReject<typename Promise::Type>& reject) {
+        PromiseFulfill<T>::call(value, resolve, reject);
+    });
+}
+
+QPromise<void> qPromise()
+{
+    return QPromise<void>([](
+        const QPromiseResolve<void>& resolve) {
+        resolve();
+    });
+}
+
+template <typename T>
+QPromise<QVector<T> > qPromiseAll(const QVector<QPromise<T> >& promises)
+{
+    return QPromise<T>::all(promises);
+}
+
+QPromise<void> qPromiseAll(const QVector<QPromise<void> >& promises)
+{
+    return QPromise<void>::all(promises);
+}
+
+} // namespace QtPromise
+
+#endif // _QTPROMISE_QPROMISEHELPERS_H

src/qtpromise/qtpromise.pri

@@ -2,6 +2,7 @@ HEADERS += \
     $$PWD/qpromise.h \
     $$PWD/qpromise.inl \
     $$PWD/qpromise_p.h \
-    $$PWD/qpromise_qfuture.inl \
     $$PWD/qpromiseerror.h \
-    $$PWD/qpromiseglobal.h
+    $$PWD/qpromisefuture.h \
+    $$PWD/qpromiseglobal.h \
+    $$PWD/qpromisehelpers.h