Set QT_PLUGIN_PATH

The MR
  1. adds a note, that the tests in the build tree depend on the install tree.
  2. extends the QT_PLUGIN_PATH with KDE_INSTALL_FULL_QTPLUGINDIR in cmake before creating the tests. That removes the need to source prefix.sh before calling cmake.

CMakeLists.txt

@@ -53,6 +53,13 @@ include(ECMAddAppIcon)
 include(CMakePackageConfigHelpers)
 include(ECMSetupQtPluginMacroNames)
 
+# append the plugins from the install tree folder to the QT_PLUGIN_PATH
+if(UNIX)
+    set(ENV{QT_PLUGIN_PATH} "$ENV{QT_PLUGIN_PATH}:${KDE_INSTALL_FULL_QTPLUGINDIR}")
+elseif(WIN32)
+    set(ENV{QT_PLUGIN_PATH} "$ENV{QT_PLUGIN_PATH};${KDE_INSTALL_FULL_QTPLUGINDIR}")
+endif()
+
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)

README.md

@@ -58,13 +58,17 @@ make
 make install
 ```
 
+Okular also builds tests in the build tree. To run them, you have to run `make install` first.
+
 If you install Okular in a different path than your system install directory it is possible that you need to run
 
 ```bash
-source build/prefix.sh; okular
+source prefix.sh
 ```
 
 so that the correct Okular instance and libraries are picked up.
+Afterwards one can run `okular` inside the shell instance.
+The source command is also required to run the tests manually.
 
 As stated above, Okular has various build targets.
 Two of them are executables.