diff --git a/scripts/rpcgen/tests/meson.build b/scripts/rpcgen/tests/meson.build
index 075b5a82cf..dfd757de7c 100644
--- a/scripts/rpcgen/tests/meson.build
+++ b/scripts/rpcgen/tests/meson.build
@@ -8,7 +8,9 @@ rpcgen_tests = files([
 test_demo = executable(
     'test_demo',
     [ 'test_demo.c' ],
-    c_args: cc_flags_relaxed_frame_limit,
+    c_args: [
+      '-Dabs_srcdir="@0@"'.format(meson.current_source_dir()),
+    ] + cc_flags_relaxed_frame_limit,
     dependencies: [
         xdr_dep, glib_dep
     ],
diff --git a/scripts/rpcgen/tests/test_demo.c b/scripts/rpcgen/tests/test_demo.c
index d6be9e236d..1cdb9cfb82 100644
--- a/scripts/rpcgen/tests/test_demo.c
+++ b/scripts/rpcgen/tests/test_demo.c
@@ -12,7 +12,7 @@ static void test_xdr(xdrproc_t proc, void *vorig, void *vnew, const char *testna
     /* 128kb is big enough for any of our test data */
     size_t buflen = 128 * 1000;
     g_autofree char *buf = g_new0(char, buflen);
-    g_autofree char *expfile = g_strdup_printf("test_demo_%s.bin", testname);
+    g_autofree char *expfile = g_strdup_printf(abs_srcdir "/test_demo_%s.bin", testname);
     g_autofree char *expected = NULL;
     size_t explen;
     size_t actlen;