+test_expect_success 'reading submodules config with "submodule--helper config"' '
+ (cd super &&
+ echo "../submodule" >expect &&
+ git submodule--helper config submodule.submodule.url >actual &&
+ test_cmp expect actual
+ )
+'
+
+test_expect_success 'writing submodules config with "submodule--helper config"' '
+ (cd super &&
+ echo "new_url" >expect &&
+ git submodule--helper config submodule.submodule.url "new_url" &&
+ git submodule--helper config submodule.submodule.url >actual &&
+ test_cmp expect actual
+ )
+'
+
+test_expect_success 'overwriting unstaged submodules config with "submodule--helper config"' '
+ test_when_finished "git -C super checkout .gitmodules" &&
+ (cd super &&
+ echo "newer_url" >expect &&
+ git submodule--helper config submodule.submodule.url "newer_url" &&
+ git submodule--helper config submodule.submodule.url >actual &&
+ test_cmp expect actual
+ )
+'
+