Qt auto test changes only effective after "rebuild" not after "build"

Question

I added an auto test project to my C++ Qt project (QT 5.15.1, MSVC 2019, host and target: Windows 10). But changes in the test source files do only take effect if I rebuild and run the test project, but not if I just build and run, which usually works fine for my main app project.

I guess I miss an important setting in my test project's .pro file.

May somebody please tell me what I am missing?

details

I have the following project structure

/project
 |- project.pro                 -- template = subdirs
 |- /app
 |   |- app.pro                 -- template = app
 |   |- main.cpp
 |   \- mainwindow and source files
 \- /tests
     |- tests.pro               -- template = subdirs
     \- /unittests
         |- unittests.pro       -- template = subdirs
         \- /objectXTest
             |- objectXTest.pro -- template = app
             |- tst_objectXTest.cpp
             \- tst_objectXTest.h

where my objectXTest.pro file is

QT += testlib
QT -= gui

SRC_DIR = ../../../app
INCLUDEPATH += \
    $${SRC_DIR} \                    # common/global project root headers
    $${SRC_DIR}/path/to/objectX      # headers relative to unit's source directory

CONFIG += qt console warn_on depend_includepath testcase
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += \
    tst_objectXTest.cpp \
    $${SRC_DIR}/path/to/objectX/objectX.cpp

HEADERS += \
    tst_objectXTest.h

and my test source is

// tst_objectXTest.h
#ifndef TST_OBJECTXTEST_H
#define TST_OBJECTXTEST_H

#include <QtTest>

// add necessary includes here
#include "objectX.h"

class ObjectXTest : public QObject {
    Q_OBJECT

public:
    ObjectXTest () {}
    ~ObjectXTest () {}

private slots:
    void initTestCase();
    void cleanupTestCase();

    void test_construction();
};

#endif // TST_OBJECTXTEST_H

and

// tst_objectXTest.cpp
#include "tst_objectXTest.h"

void ObjectXTest::initTestCase() { }
void ObjectXTest::cleanupTestCase() { }

void ObjectXTest::test_construction() {
    auto p_ox = new ObjectX();
    QWARN("some message");
    delete p_ox;
}

QTEST_APPLESS_MAIN(ObjectXTest)

I tried changing the message in QWARN above, but re-executing will always print the text from last time re-building the test project.

Answer 1

I solved this myself, by the following steps (after making the above changes):

1. close Qt Creator
2. delete the project.pro.user file in the project root directory
3. re-open the Project in Qt Creator
4. (probably this was not necessary) execute qmake at project.pro

Now a simple build does update files in the build directory partially to my changes and changes get effective immediately.