diff --git a/.gitignore b/.gitignore
index 660176b60..f0f1c02aa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,5 +9,6 @@ gdlde/
 gdlde*.zip
 .vscode
 .idea/
+Testing/
 2020.2.zip
 qhull-2020.2
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3bcb5c75e..fb63ef82b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -161,14 +161,7 @@ set(JPEGDIR "" CACHE PATH "GDL: Specify the JPEG directory tree")
 set(SZIPDIR "" CACHE PATH "GDL: Specify the SZip directory tree")
 
 set(GDL_DATA_DIR "/share/gnudatalanguage" CACHE PATH "GDL: data directory relative to CMAKE_INSTALL_PREFIX")
-set(GDL_LIB_DIR "" CACHE PATH "GDL: library directory relative to CMAKE_INSTALL_PREFIX")
-#define (for plplotdriver/CMakeLists.txt) the GDL_DRV_DIR where the drivers will be installed.
-#if GDL_LIB_DIR is empty, it will be the default (GDL_DATA_DIR/drivers) otherwise it is GDL_LIB_DIR (not GDL_LIB_DIR/drivers)
-if ( GDL_LIB_DIR STREQUAL "" OR NOT GDL_LIB_DIR)
- set (GDL_DRV_DIR "${CMAKE_INSTALL_PREFIX}/${GDL_DATA_DIR}/drivers") # CACHE PATH "GDL: where the drivers will be installed.")
-else()
- set (GDL_DRV_DIR "${GDL_LIB_DIR}" ) # CACHE PATH "GDL: where the drivers will be installed.")
-endif()
+set(GDL_LIB_DIR "/lib/gnudatalanguage" CACHE PATH "GDL: library directory relative to CMAKE_INSTALL_PREFIX")
 # check for 64-bit OS
 if(${CMAKE_SIZEOF_VOID_P} EQUAL 8)
     set(HAVE_64BIT_OS 1)
diff --git a/INSTALL.CMake b/INSTALL.CMake
index f4faa129e..ad9311bbe 100644
--- a/INSTALL.CMake
+++ b/INSTALL.CMake
@@ -41,6 +41,9 @@ Other options include:
 - GDL_DATA_DIR (default: /share/gnudatalanguage) to specify
   a custom installation location for GDL files 
   (a subdirectory of the main installation prefix)
+- GDL_LIB_DIR (default: /lib/gnudatalanguage) to specify
+  a custom installation location for local PlPlot driver files
+  (a subdirectory of the main installation prefix)
 
 The list of all GDL-related options accepted by CMake along
 with their default values can be obtained by calling:
diff --git a/config.h.cmake b/config.h.cmake
index 0eb7a2f01..e87c72991 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -1,10 +1,8 @@
 #ifndef __CONFIG_H__
 #define __CONFIG_H__
 
-#define EXEC_PREFIX "@CMAKE_INSTALL_PREFIX@"
-#define GDLDATADIR "@CMAKE_INSTALL_PREFIX@@GDL_DATA_DIR@"
-#define GDLLIBDIR "@GDL_LIB_DIR@"
-#define GDL_DRV_DIR "@GDL_DRV_DIR@"
+#cmakedefine GDL_DATA_DIR "@GDL_DATA_DIR@"
+#cmakedefine GDL_LIB_DIR "@GDL_LIB_DIR@"
 
 #define _CRT_SECURE_NO_WARNINGS
 
diff --git a/scripts/build_gdl.sh b/scripts/build_gdl.sh
index 2518ecb51..12ae5419f 100755
--- a/scripts/build_gdl.sh
+++ b/scripts/build_gdl.sh
@@ -559,11 +559,12 @@ function install_gdl {
 
 function test_gdl {
     log "Testing GDL..."
-    cd ${ROOT_DIR}/build
-    if [ -f ${GDL_DIR}/CMakeModules/CodeCoverage.cmake ]; then
+    cd "${ROOT_DIR}/build" || exit 1
+    if [ -f "${GDL_DIR}/CMakeModules/CodeCoverage.cmake" ]; then
         make codecov || exit 1
     else
-        CTEST_OUTPUT_ON_FAILURE=1 make test || exit 1
+        # since we do not install anything we need to set the driver path to the directory of the compiles drivers
+        CTEST_OUTPUT_ON_FAILURE=1 GDL_DRV_DIR="${ROOT_DIR}/build/src/plplotdriver" make test || exit 1
     fi
 }
 
diff --git a/src/gdl.cpp b/src/gdl.cpp
index 6b793296f..0c32246fe 100644
--- a/src/gdl.cpp
+++ b/src/gdl.cpp
@@ -215,7 +215,7 @@ namespace MyPaths {
   if (length > 0)
   {
     path = (char*)malloc(length + 1);
-    if (!path) return std::string(".");
+    if (!path) return {"."};
     wai_getExecutablePath(path, length, &dirname_length);
     path[dirname_length] = '\0';
 //    printf("  dirname: %s\n", path);
@@ -223,7 +223,7 @@ namespace MyPaths {
     free(path);
     return pathstring;
   }
-  return std::string(".");
+  return {"."};
 }
 }
 
@@ -236,43 +236,44 @@ int main(int argc, char *argv[])
   bool setQuietSysvar=false;
   bool willSuppressEditInput=false;
   std::string myMessageBoxName="";
-  
-//The default installation location --- will not always be there.  
-  gdlDataDir = std::string(GDLDATADIR);
-  gdlLibDir = std::string(GDLLIBDIR);
+
+  // The default installation location --- will not always be there.
+  gdlDataDir = std::string(GDL_DATA_DIR);
+  gdlLibDir = std::string(GDL_LIB_DIR);
+
 #ifdef _WIN32
   std::replace(gdlDataDir.begin(), gdlDataDir.end(), '/', '\\');
   std::replace(gdlLibDir.begin(), gdlLibDir.end(), '/', '\\');
-#endif 
+#endif
+  // make sure dirs are prefixed with the system's path separator
+  if (gdlDataDir.at(0) != lib::PathSeparator()) gdlDataDir.assign(lib::PathSeparator() + gdlDataDir);
+  if (gdlLibDir.at(0) != lib::PathSeparator()) gdlLibDir.assign(lib::PathSeparator() + gdlLibDir);
 
 //check where is the executable being run
- whereami_gdl=MyPaths::getExecutablePath();
-// if I am at a 'bin' location, then there are chances that I've bee INSTALLED, so all the resources I need can be accessed relatively to this 'bin' directory.
-// if not, then I'm probably just a 'build' gdl and my ressources may (should?) be in the default location GDLDATADIR
-  std::size_t pos=whereami_gdl.rfind("bin");
-  if (pos == whereami_gdl.size()-3) { //we are the installed gdl!
-    gdlDataDir.assign( whereami_gdl+ lib::PathSeparator() + ".." + lib::PathSeparator() + "share" + lib::PathSeparator() + "gnudatalanguage") ;
-//    std::cerr<<"installed at: "<<gdlDataDir<<std::endl;
+
+  auto whereami = MyPaths::getExecutablePath();
+// if I am at a 'bin' location, then there are chances that I've been INSTALLED, so all the resources I need can be accessed relatively to this 'bin' directory.
+// if not, then I'm probably just a 'build' gdl and my resources may (should?) be in the default location GDL_DATA_DIR
+  auto pos = whereami.rfind("bin");
+  if (pos != std::string::npos) { // we are the installed gdl!
+    // use pos - 1, so we remove the path separator, too
+    gdlDataDir.assign(whereami.substr(0, pos - 1) + gdlDataDir);
+    gdlLibDir.assign(whereami.substr(0, pos - 1) + gdlLibDir);
   }
 
 //PATH. This one is often modified by people before starting GDL.
-  string gdlPath=GetEnvPathString("GDL_PATH"); //warning: is a Path, use system separator.
-  if( gdlPath == "") gdlPath=GetEnvString("IDL_PATH"); //warning: is a Path, use system separator.
-  if( gdlPath == "") gdlPath = gdlDataDir + lib::PathSeparator() + "lib";
-
-//LIBDIR. Can be '' in which case the location of drivers is deduced from the location of
-//the executable (OSX, Windows, unix in user-installed mode).
-  string driversPath = GetEnvPathString("GDL_DRV_DIR");
-  if (driversPath == "") { //NOT enforced by GDL_DRV_DIR
-    driversPath = gdlLibDir; //e.g. Fedora
-    if (driversPath == "") { //NOT enforced by GDLLIBDIR at build : not a distro
-      driversPath = gdlDataDir + lib::PathSeparator() + "drivers"; //deduced from the location of the executable 
-    }
-  }
+  auto gdlPath = GetEnvPathString("GDL_PATH");
+  if( gdlPath.empty()) gdlPath = GetEnvPathString("IDL_PATH");
+  if( gdlPath.empty()) gdlPath = gdlDataDir + lib::PathSeparator() + "lib";
+
+  auto driversPath = GetEnvPathString("GDL_DRV_DIR");
+  // use the identical approach already used for figuring out the path to out *.pro files etc.
+  if (driversPath.empty()) driversPath = gdlLibDir;
+
   //various env set?
   char* wantCalm = getenv("IDL_QUIET");
   if (wantCalm != NULL) setQuietSysvar=true;
-  
+
   //drivers if local
   useLocalDrivers=false;
   bool driversNotFound=false;
@@ -621,19 +622,6 @@ int main(int argc, char *argv[])
   {
     cerr << "- Please report bugs, feature or help requests and patches at: https://github.com/gnudatalanguage/gdl" << endl << endl;
   }
-//   else
-//     {
-//       // if path not given, add users home
-//       if( !PathGiven(startup))
-// 	{
-// 	  string home=GetEnvString("HOME");
-// 	  if( home != "") 
-// 	    {
-// 	      AppendIfNeeded(home,"/");
-// 	      startup=home+startup;
-// 	    }
-// 	}
-//     }
 
 #ifdef USE_MPI
   if (iAmMaster) {
diff --git a/src/plplotdriver/CMakeLists.txt b/src/plplotdriver/CMakeLists.txt
index a48742c10..28eb2ad10 100644
--- a/src/plplotdriver/CMakeLists.txt
+++ b/src/plplotdriver/CMakeLists.txt
@@ -5,40 +5,52 @@ if(INSTALL_LOCAL_DRIVERS)
 
   #these drivers are always present
   list(APPEND WHAT "ps" "svg" "mem")
-  list(APPEND WHATFILES "mem.driver_info" "svg.driver_info" "ps.driver_info")
   add_library(ps MODULE ps.c)
-  target_link_libraries(
-      ps
-      ${PLPLOT_LIBRARIES}
-      )
+  # Copy thr driver info file after building the target so we can use the build-dir directly when testing
+  add_custom_command(
+    TARGET ps POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+    ${CMAKE_SOURCE_DIR}/src/plplotdriver/ps.driver_info
+    ${CMAKE_CURRENT_BINARY_DIR}/ps.driver_info
+  )
+  target_link_libraries(ps ${PLPLOT_LIBRARIES})
   add_library(svg MODULE svg.c)
-  target_link_libraries(
-      svg
-      ${PLPLOT_LIBRARIES}
-      )
+  # Copy thr driver info file after building the target so we can use the build-dir directly when testing
+  add_custom_command(
+    TARGET svg POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+    ${CMAKE_SOURCE_DIR}/src/plplotdriver/svg.driver_info
+    ${CMAKE_CURRENT_BINARY_DIR}/svg.driver_info
+  )
+  target_link_libraries(svg ${PLPLOT_LIBRARIES})
   add_library(mem MODULE mem.c)
-  target_link_libraries(
-      mem
-      ${PLPLOT_LIBRARIES}
-      )
+  # Copy thr driver info file after building the target so we can use the build-dir directly when testing
+  add_custom_command(
+    TARGET mem POST_BUILD
+    COMMAND ${CMAKE_COMMAND} -E copy
+    ${CMAKE_SOURCE_DIR}/src/plplotdriver/mem.driver_info
+    ${CMAKE_CURRENT_BINARY_DIR}/mem.driver_info
+  )
+  target_link_libraries(mem ${PLPLOT_LIBRARIES})
 
   #driver wxwidgets
   if (HAVE_LIBWXWIDGETS) 
     set(LINK_DIRECTORIES ${LINK_DIRECTORIES} ${wxWidgets_LIBRARY_DIRS})
     foreach(WXDEF ${wxWidgets_DEFINITIONS})
-        add_definitions(-D${WXDEF})
+      add_definitions(-D${WXDEF})
     endforeach(WXDEF ${wxWidgets_DEFINITIONS})
     include_directories( ${wxWidgets_INCLUDE_DIRS})
     add_library(wxwidgets MODULE deprecated_wxwidgets.cpp deprecated_wxwidgets_app.cpp deprecated_wxwidgets_dc.cpp deprecated_wxwidgets_gc.cpp)
-    target_link_libraries(
-        wxwidgets
-      ${PLPLOT_LIBRARIES}
-        ${wxWidgets_LIBRARIES}
-     )
-     list(APPEND WHAT "wxwidgets")
-     list(APPEND WHATFILES  "wxwidgets.driver_info")
-   endif(HAVE_LIBWXWIDGETS)
-
+    # Copy thr driver info file after building the target so we can use the build-dir directly when testing
+    add_custom_command(
+      TARGET wxwidgets POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy
+      ${CMAKE_SOURCE_DIR}/src/plplotdriver/wxwidgets.driver_info
+      ${CMAKE_CURRENT_BINARY_DIR}/wxwidgets.driver_info
+    )
+    target_link_libraries(wxwidgets ${PLPLOT_LIBRARIES} ${wxWidgets_LIBRARIES})
+    list(APPEND WHAT "wxwidgets")
+  endif(HAVE_LIBWXWIDGETS)
  
   # driver xwin -- check if X11 is present
   find_package(X11 QUIET)
@@ -47,17 +59,17 @@ if(INSTALL_LOCAL_DRIVERS)
     set(LIBRARIES ${LIBRARIES} ${X11_LIBRARIES})
     include_directories(${X11_INCLUDE_DIR})
     add_library(xwin MODULE xwin.c)
-    target_link_libraries(
-        xwin
-      ${PLPLOT_LIBRARIES}
-        ${X11_LIBRARIES}
-        )
-    list (APPEND WHAT "xwin")
-    list(APPEND WHATFILES "wxin.driver_info")
+    # Copy thr driver info file after building the target so we can use the build-dir directly when testing
+    add_custom_command(
+      TARGET xwin POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy
+      ${CMAKE_SOURCE_DIR}/src/plplotdriver/xwin.driver_info
+      ${CMAKE_CURRENT_BINARY_DIR}/xwin.driver_info
+    )
+    target_link_libraries(xwin ${PLPLOT_LIBRARIES} ${X11_LIBRARIES})
+    list(APPEND WHAT "xwin")
  endif(X11_FOUND)
 
-
-
   if(WIN32)
     set(DYNAMIC_SUFFIX ".dll")
   else(WIN32)
@@ -65,9 +77,9 @@ if(INSTALL_LOCAL_DRIVERS)
   endif(WIN32)
 
   foreach(v IN LISTS WHAT)
-  set_target_properties(${v} PROPERTIES   PREFIX ""  SUFFIX ${DYNAMIC_SUFFIX} )
-  install(TARGETS ${v} DESTINATION ${GDL_DRV_DIR})
-  install( FILES ${v}.driver_info DESTINATION ${GDL_DRV_DIR})
+    set_target_properties(${v} PROPERTIES   PREFIX ""  SUFFIX ${DYNAMIC_SUFFIX} )
+    install(TARGETS ${v} DESTINATION ${CMAKE_INSTALL_PREFIX}/${GDL_LIB_DIR})
+    install(FILES ${v}.driver_info DESTINATION ${CMAKE_INSTALL_PREFIX}/${GDL_LIB_DIR})
   endforeach()
 
 endif(INSTALL_LOCAL_DRIVERS)
diff --git a/src/pythongdl.cpp b/src/pythongdl.cpp
index b02fb7559..566dd5153 100644
--- a/src/pythongdl.cpp
+++ b/src/pythongdl.cpp
@@ -585,7 +585,7 @@ extern "C" {
 //    if( gdlPath == "") gdlPath=GetEnvString("IDL_PATH");
 //    if( gdlPath == "")
 //      {
-//        gdlPath = "+" GDLDATADIR "/lib";
+//        gdlPath = "+" GDL_DATA_DIR "/lib";
 //      }
 //    SysVar::SetGDLPath( gdlPath);
     
diff --git a/src/str.cpp b/src/str.cpp
index 77cfcd415..47aaca382 100644
--- a/src/str.cpp
+++ b/src/str.cpp
@@ -45,25 +45,25 @@ namespace lib {
   std::string PathSeparator()
   {
 #ifdef _WIN32
-    if (lib::posixpaths) return std::string ("/");
-    return std::string ("\\");
+    if (lib::posixpaths) return {"/"};
+    return {"\\"};
 #else
-    return std::string ("/");
+    return {"/"};
 #endif
   }
   
   std::string SearchPathSeparator()
   {
 #ifdef _WIN32
-    return std::string (";");
+    return {";"};
 #else
-    return std::string (":");
+    return {":"};
 #endif
   }
   
   std::string ParentDirectoryIndicator()
   {
-    return std::string ("..");
+    return {".."};
   }
 }
 //using namespace std;
@@ -73,16 +73,13 @@ namespace lib {
 std::string GetEnvString(const char* env)
 {
   char* c=getenv(env);
-  if( !c) return std::string("");
-  return std::string(c);
+  if( !c) return {""};
+  return {c};
 }
 //same but for a path: separator will be '\' for _WIN32
 std::string GetEnvPathString(const char* env)
 {
-  std::string ret("");
-  char* c=getenv(env);
-  if( !c) return ret;
-  ret=std::string(c);
+  std::string ret = GetEnvString(env);
 #ifdef _WIN32
     std::replace(ret.begin(), ret.end(), '/', '\\');
 #endif