diff --git a/qcoro.spec b/qcoro.spec
index 88db546..4532986 100644
--- a/qcoro.spec
+++ b/qcoro.spec
@@ -32,6 +32,8 @@ BuildRequires: cmake(Qt5Quick)
 BuildRequires: cmake(Qt5Test)
 BuildRequires: cmake(Qt5WebSockets)
 BuildRequires: cmake(Qt5Widgets)
+# For tests only: https://github.com/danvratil/qcoro/issues/139
+BuildRequires: qt5-qtbase-private-devel
 %endif
 
 %if 0%{?use_qt6}
@@ -44,6 +46,8 @@ BuildRequires: cmake(Qt6Quick)
 BuildRequires: cmake(Qt6Test)
 BuildRequires: cmake(Qt6WebSockets)
 BuildRequires: cmake(Qt6Widgets)
+# For tests only: https://github.com/danvratil/qcoro/issues/139
+BuildRequires: qt6-qtbase-private-devel
 %endif
 
 BuildRequires: cmake