diff --git a/tests/ECMQtDeclareLoggingCategoryTest/testmain.cpp b/tests/ECMQtDeclareLoggingCategoryTest/testmain.cpp
index 4abcd52..00253d6 100644
--- a/tests/ECMQtDeclareLoggingCategoryTest/testmain.cpp
+++ b/tests/ECMQtDeclareLoggingCategoryTest/testmain.cpp
@@ -1,108 +1,113 @@
 /*
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 
  * 1. Redistributions of source code must retain the copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote products 
  *    derived from this software without specific prior written permission.
  * 
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <QCoreApplication>
 
 #include "log1.h"
 #include "log2.h"
 #include "log3.h"
 
 #include <iostream>
 
-int main(int argc, char **argv) {
+int main(int argc, char **argv)
+{
+    // Make the unit test more reliable on system which have these env vars set
+    qunsetenv("QT_LOGGING_CONF");
+    qunsetenv("QT_LOGGING_RULES");
+
     QCoreApplication qapp(argc, argv);
 
     bool success = true;
 
     // NB: we cannot test against QtInfoMsg, as that (a) does not exist before
     // Qt 5.5, and (b) has incorrect semantics in Qt 5.5, in that it is
     // treated as more severe than QtCriticalMsg.
 
     if (log1().categoryName() != QLatin1String("log.one")) {
         qWarning("log1 category was \"%s\", expected \"log.one\"", log1().categoryName());
         success = false;
     }
 #if QT_VERSION < QT_VERSION_CHECK(5, 4, 0)
     if (!log1().isDebugEnabled()) {
         qWarning("log1 debug messages were not enabled");
         success = false;
     }
 #else
     if (log1().isDebugEnabled()) {
         qWarning("log1 debug messages were enabled");
         success = false;
     }
     if (!log1().isWarningEnabled()) {
         qWarning("log1 warning messages were not enabled");
         success = false;
     }
 #endif
 
     if (foo::bar::log2().categoryName() != QLatin1String("log.two")) {
         qWarning("log2 category was \"%s\", expected \"log.two\"", foo::bar::log2().categoryName());
         success = false;
     }
 #if QT_VERSION < QT_VERSION_CHECK(5, 4, 0)
     if (!foo::bar::log2().isDebugEnabled()) {
         qWarning("log2 debug messages were not enabled");
         success = false;
     }
 #else
     if (foo::bar::log2().isDebugEnabled()) {
         qWarning("log2 debug messages were enabled");
         success = false;
     }
     if (!foo::bar::log2().isWarningEnabled()) {
         qWarning("log2 warning messages were not enabled");
         success = false;
     }
 #endif
 
     if (log3().categoryName() != QLatin1String("three")) {
         qWarning("log3 category was \"%s\", expected \"three\"", log3().categoryName());
         success = false;
     }
 #if QT_VERSION < QT_VERSION_CHECK(5, 4, 0)
     if (!log3().isDebugEnabled()) {
         qWarning("log3 debug messages were not enabled");
         success = false;
     }
 #else
     if (log3().isDebugEnabled()) {
         qWarning("log3 debug messages were enabled");
         success = false;
     }
     if (log3().isWarningEnabled()) {
         qWarning("log3 warning messages were enabled");
         success = false;
     }
     if (!log3().isCriticalEnabled()) {
         qWarning("log3 critical messages were not enabled");
         success = false;
     }
 #endif
 
     return success ? 0 : 1;
 }