diff --git a/unittest/c-library/test_library_config.cpp b/unittest/c-library/test_library_config.cpp
index f196f800da..8a3d08cb33 100644
--- a/unittest/c-library/test_library_config.cpp
+++ b/unittest/c-library/test_library_config.cpp
@@ -74,7 +74,7 @@ TEST(LAMMPSConfig, package_name)
         EXPECT_EQ(lammps_config_package_name(numpkgs + 10, buf, 128), 0);
         EXPECT_THAT(buf, StrEq(""));
     } else {
-        EXPECT_EQ(lammps_config_package_name(0, buf, 128), 1);
+        EXPECT_EQ(lammps_config_package_name(0, buf, 128), 0);
         EXPECT_THAT(buf, StrEq(""));
     }
 };