diff --git a/src/tests.h b/src/tests.h
index ce6edda06..a35b5acf3 100644
--- a/src/tests.h
+++ b/src/tests.h
@@ -14,6 +14,7 @@ extern "C" {
     struct ship;
     struct item_type;
     struct building_type;
+    struct ship_type;
     struct terrain_type;
 
     void test_cleanup(void);
diff --git a/src/util/attrib.test.c b/src/util/attrib.test.c
index aba7b25db..be3987bfe 100644
--- a/src/util/attrib.test.c
+++ b/src/util/attrib.test.c
@@ -17,20 +17,27 @@ static void test_attrib_new(CuTest * tc)
 
 static void test_attrib_add(CuTest * tc)
 {
-    attrib_type at_test = { "test" };
+    attrib_type at_foo = { "foo" };
+    attrib_type at_bar = { "bar" };
     attrib *a, *alist = 0;
-    CuAssertPtrNotNull(tc, (a = a_new(&at_test)));
+    CuAssertPtrNotNull(tc, (a = a_new(&at_foo)));
     CuAssertPtrEquals(tc, a, a_add(&alist, a));
     CuAssertPtrEquals(tc, a, alist);
+    CuAssertPtrEquals(tc, 0, alist->nexttype);
 
-    CuAssertPtrNotNull(tc, (a = a_add(&alist, a_new(&at_test))));
+    CuAssertPtrNotNull(tc, (a = a_add(&alist, a_new(&at_foo))));
     CuAssertPtrEquals(tc, alist->next, a);
-    CuAssertPtrEquals(tc, alist->nexttype, a);
+    CuAssertPtrEquals(tc, 0, alist->nexttype);
+
+    CuAssertPtrNotNull(tc, (a = a_add(&alist, a_new(&at_bar))));
+    CuAssertPtrEquals(tc, alist->next->next, a);
+    CuAssertPtrEquals(tc, a, alist->nexttype);
 }
 
 CuSuite *get_attrib_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
     SUITE_ADD_TEST(suite, test_attrib_new);
+    SUITE_ADD_TEST(suite, test_attrib_add);
     return suite;
 }