diff --git a/gio/generated/generate_code.py b/gio/generated/generate_code.py
index f49d8dc99..a238e22c4 100644
--- a/gio/generated/generate_code.py
+++ b/gio/generated/generate_code.py
@@ -37,8 +37,9 @@ if __name__ == "__main__":
 
     shutil.copyfile(opts.api_raw, api_xml)
 
-    cmd = [opts.gapi_fixup, "--api=" + api_xml,
-                           "--metadata=" + opts.metadata]
+    cmd = [opts.gapi_fixup, "--api=" + api_xml]
+    if opts.metadata:
+        cmd += ["--metadata=" + opts.metadata]
     if opts.symbols:
         cmd.extend(['--symbols=' + opts.symbols])
     subprocess.check_call(cmd)
diff --git a/meson.build b/meson.build
index 9640e709c..973200cfc 100644
--- a/meson.build
+++ b/meson.build
@@ -113,6 +113,7 @@ gtk_dep = dependency('gtk+-3.0', version: gtk_required_version, required: false)
 if gtk_dep.found() and atk_dep.found() and pango_dep.found()
     subdir('gtk')
     subdir('sample/GtkDemo')
+    subdir('sample/valtest')
     has_gtk = true
 else
     has_gtk = false
diff --git a/sample/valtest/generated/meson.build b/sample/valtest/generated/meson.build
new file mode 100644
index 000000000..ce46097ef
--- /dev/null
+++ b/sample/valtest/generated/meson.build
@@ -0,0 +1,33 @@
+generated_sources = [
+    'Gtksharp_Valobj.cs',
+]
+
+source_gen = custom_target(assembly_name + 'codegen',
+    input: raw_api_fname,
+    output: generated_sources,
+    command: [
+        generate_api,
+        '--api-raw', '@INPUT@',
+        '--gapi-fixup', gapi_fixup.full_path(),
+        '--metadata', metadata_fname,
+        '--symbols', symbols,
+        '--gapi-codegen', gapi_codegen.full_path(),
+        '--extra-includes', glib_api_includes,
+        '--extra-includes', pango_api_includes,
+        '--extra-includes', gio_api_includes,
+        '--extra-includes', cairo_api_includes,
+        '--extra-includes', gdk_api_includes,
+        '--extra-includes', atk_api_includes,
+        '--extra-includes', gtk_api_includes,
+        '--out', meson.current_build_dir(),
+        '--files', ';'.join(generated_sources),
+        '--assembly-name', assembly_name,
+        '--schema', schema,
+    ],
+    depends: [gapi_codegen, gapi_fixup])
+
+api_xml = custom_target(pkg + '_api_xml',
+        input: raw_api_fname,
+        output: pkg + '-api.xml',
+        command: [generate_api, '--fakeglue'],
+        depends: [source_gen])
diff --git a/sample/valtest/meson.build b/sample/valtest/meson.build
new file mode 100644
index 000000000..ca40a9314
--- /dev/null
+++ b/sample/valtest/meson.build
@@ -0,0 +1,15 @@
+pkg = 'valobj'
+assembly_name = pkg + '-sharp'
+symbols = ''
+
+raw_api_fname = join_paths(meson.current_source_dir(), pkg + '-api.xml')
+metadata_fname = ''
+
+vallib = library('valobj',
+		'valobj.c',
+		dependencies: [gtk_dep])
+
+subdir('generated')
+executable('valtest', 'Valtest.cs', source_gen,
+		cs_args: ['-unsafe'],
+		dependencies: [gtk_sharp_dep])