diff --git a/README.rst b/README.rst
index af88059d..355a8b9b 100644
--- a/README.rst
+++ b/README.rst
@@ -50,7 +50,7 @@ Dependencies
 Requirements to build
 =====================
 
-- Meson 0.54.0 or later
+- Meson 0.56.0 or later
 - Ninja
 - PyGObject (optional to run unit tests)
 - gi-docgen (optional to generate API documentation)
diff --git a/meson.build b/meson.build
index c317991e..1b0536ca 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project('libhinawa', 'c',
   version: '2.6.1',
   license: 'LGPL-2.1+',
-  meson_version: '>= 0.54.0',
+  meson_version: '>= 0.56.0',
 )
 
 # Detect support level in Linux sound subsystem.
diff --git a/src/meson.build b/src/meson.build
index 8c1d8ca3..a49de66d 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -90,9 +90,6 @@ hinawa_gir = gnome.generate_gir(myself,
   install: true,
 )
 
-# For test.
-builddir = meson.current_build_dir()
-
 # For wrap dependency system.
 hinawa_dep = declare_dependency(
   link_with: myself,
diff --git a/tests/meson.build b/tests/meson.build
index 9de4f4c6..1117a673 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -8,6 +8,9 @@ tests = [
   'hinawa-functions',
 ]
 
+
+builddir = join_paths(meson.project_build_root(), 'src')
+
 envs = environment()
 envs.append('LD_LIBRARY_PATH', builddir, separator : ':')
 envs.append('GI_TYPELIB_PATH', builddir, separator : ':')