diff --git a/.gitlab/cp-plug-in-subfolder.py b/.gitlab/cp-plug-in-subfolder.py
new file mode 100644
index 0000000000..007d28aa04
--- /dev/null
+++ b/.gitlab/cp-plug-in-subfolder.py
@@ -0,0 +1,32 @@
+#!/usr/bin/python3
+
+# Equivalent to:
+# configure_file(input: src,
+#                output: name / src,
+#                copy: true,
+#                install_dir: gimpplugindir / 'plug-ins' / name,
+#                install_mode: 'rwxr-xr-x')
+# Except that configure_file() does not accept output in a subdirectory. So we
+# use this wrapper for now.
+# See: https://github.com/mesonbuild/meson/issues/2320
+import os
+import shutil
+import stat
+import sys
+
+src_file = sys.argv[1]
+dir_name = sys.argv[2]
+dummy_path = None
+if len(sys.argv) > 3:
+  dummy_path = sys.argv[3]
+
+os.makedirs(dir_name, exist_ok=True)
+
+file_name = os.path.basename(src_file)
+dst_file  = os.path.join(dir_name, file_name)
+shutil.copyfile(src_file, dst_file)
+os.chmod(dst_file, stat.S_IRWXU | stat.S_IRGRP | stat.S_IXGRP | stat.S_IROTH | stat.S_IXOTH)
+
+if dummy_path is not None:
+  # Just touch the dummy file.
+  open(dummy_path, mode='w').close()
diff --git a/build/windows/installer/meson.build b/build/windows/installer/meson.build
index a9ee6af838..b3f61fcb4f 100644
--- a/build/windows/installer/meson.build
+++ b/build/windows/installer/meson.build
@@ -1,6 +1,27 @@
 subdir('lang')
 
 source_splash=meson.project_source_root() + '/data/images/gimp-splash.png'
+
+# make GIMP runnable without being installed.
+env=environment()
+
+menu_paths=meson.project_build_root() / 'menus:' + meson.project_source_root() / 'menus'
+env.set('GIMP_TESTING_MENUS_PATH', menu_paths)
+
+env.set('GIMP_TESTING_PLUGINDIRS', meson.project_build_root() / 'plug-ins:')
+env.append('GIMP_TESTING_PLUGINDIRS', meson.project_build_root() / 'plug-ins/python')
+env.append('GIMP_TESTING_PLUGINDIRS', meson.project_build_root() / 'plug-ins/common/test-plug-ins/')
+
+env.append('GI_TYPELIB_PATH', meson.project_build_root() / 'libgimp')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimp')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpbase')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpcolor')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpconfig')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpmath')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpmodule')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpthumb')
+env.append('LD_LIBRARY_PATH', meson.project_build_root() / 'libgimpwidgets')
+
 installsplash = custom_target('installsplash-devel.bmp',
   input : [ 'splash2installer.py' ],
   depend_files: [ source_splash ],
@@ -9,5 +30,6 @@ installsplash = custom_target('installsplash-devel.bmp',
              '--batch-interpreter', 'python-fu-eval',
              '-b', '-', '--quit'],
   feed: true,
-  build_by_default: true
+  build_by_default: true,
+  env: env
 )
diff --git a/plug-ins/common/meson.build b/plug-ins/common/meson.build
index f5e637a8fa..da27e601a8 100644
--- a/plug-ins/common/meson.build
+++ b/plug-ins/common/meson.build
@@ -213,7 +213,7 @@ foreach plugin : common_plugins_list
     )
   endif
 
-  executable(plugin_name,
+  plugin_exe = executable(plugin_name,
     plugin_sources,
     include_directories: [ rootInclude, ],
     link_with : [
@@ -230,4 +230,15 @@ foreach plugin : common_plugins_list
     install: true,
     install_dir: gimpplugindir / 'plug-ins' / plugin_name,
   )
+
+  # Ugly trick to copy executables into subfolders so that we can run GIMP from
+  # the build directory without installing it.
+  custom_target('test-' + plugin_name,
+    input: [ plugin_exe ],
+    output: [ plugin_name + '.dummy' ],
+    command: [ python, meson.project_source_root() / '.gitlab/cp-plug-in-subfolder.py',
+               plugin_exe, meson.current_build_dir() / 'test-plug-ins' / plugin_name,
+               meson.current_build_dir() / 'test-plug-ins' / plugin_name + '.dummy' ],
+    build_by_default: true,
+  )
 endforeach
diff --git a/plug-ins/python/meson.build b/plug-ins/python/meson.build
index 1b84c01c44..773ef5cce9 100644
--- a/plug-ins/python/meson.build
+++ b/plug-ins/python/meson.build
@@ -25,10 +25,17 @@ subdir('python-console')
 
 foreach plugin : plugins
   name = plugin.get('name')
-  srcs = plugin.get('srcs', name + '.py')
+  srcs = plugin.get('srcs', [name + '.py'])
 
   install_data(srcs, install_dir: gimpplugindir / 'plug-ins' / name,
                install_mode: 'rwxr-xr-x')
+
+  foreach src : srcs
+    # Ugly trick to copy Python plug-ins into subfolders so that we can run GIMP
+    # from the build directory without installing it.
+    run_command(python, meson.project_source_root() / '.gitlab/cp-plug-in-subfolder.py',
+                meson.current_source_dir() / src, meson.current_build_dir() / name, check: true)
+  endforeach
 endforeach
 
 
diff --git a/plug-ins/python/python-console/meson.build b/plug-ins/python/python-console/meson.build
index 2399c14cbf..f6042dfc84 100644
--- a/plug-ins/python/python-console/meson.build
+++ b/plug-ins/python/python-console/meson.build
@@ -1,5 +1,5 @@
 
 plugins += {
   'name': 'python-console',
-  'srcs': files('pyconsole.py', 'python-console.py'),
+  'srcs': [ 'python-console/pyconsole.py', 'python-console/python-console.py' ],
 }