diff --git a/src/economy.test.c b/src/economy.test.c
index 9339f27d3..70bff245c 100644
--- a/src/economy.test.c
+++ b/src/economy.test.c
@@ -37,7 +37,7 @@ static void test_give_control_building(CuTest * tc)
     test_setup();
     f = test_create_faction(NULL);
     r = test_create_region(0, 0, NULL);
-    b = test_create_building(r, 0);
+    b = test_create_building(r, NULL);
     u1 = test_create_unit(f, r);
     u_set_building(u1, b);
     u2 = test_create_unit(f, r);
@@ -58,7 +58,7 @@ static void test_give_control_ship(CuTest * tc)
     test_setup();
     f = test_create_faction(NULL);
     r = test_create_region(0, 0, NULL);
-    sh = test_create_ship(r, 0);
+    sh = test_create_ship(r, NULL);
     u1 = test_create_unit(f, r);
     u_set_ship(u1, sh);
     u2 = test_create_unit(f, r);
@@ -586,7 +586,7 @@ static void test_modify_production(CuTest *tc) {
     rt_silver = get_resourcetype(R_SILVER);
     itype = test_create_itemtype("stone");
     rtype = itype->rtype;
-    u = test_create_unit(test_create_faction(NULL), test_create_region(0,0,0));
+    u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
     make_item(u, itype, 1);
     CuAssertPtrNotNull(tc, test_find_messagetype(u->faction->msgs, "error_cannotmake"));
     CuAssertIntEquals(tc, 0, get_item(u, itype));
diff --git a/src/kernel/save.test.c b/src/kernel/save.test.c
index 8f0163d98..4e6e0e2d4 100644
--- a/src/kernel/save.test.c
+++ b/src/kernel/save.test.c
@@ -164,7 +164,7 @@ static void test_readwrite_building(CuTest * tc)
 
     test_setup();
     r = test_create_region(0, 0, NULL);
-    b = test_create_building(r, 0);
+    b = test_create_building(r, NULL);
     free(b->name);
     b->name = str_strdup("  Hodor  ");
     CuAssertStrEquals(tc, "  Hodor  ", b->name);
@@ -197,7 +197,7 @@ static void test_readwrite_ship(CuTest * tc)
 
     test_setup();
     r = test_create_region(0, 0, NULL);
-    sh = test_create_ship(r, 0);
+    sh = test_create_ship(r, NULL);
     free(sh->name);
     sh->name = str_strdup("  Hodor  ");
     CuAssertStrEquals(tc, "  Hodor  ", sh->name);
diff --git a/src/kernel/ship.test.c b/src/kernel/ship.test.c
index d558d75d6..69766276c 100644
--- a/src/kernel/ship.test.c
+++ b/src/kernel/ship.test.c
@@ -410,7 +410,7 @@ static ship *setup_ship(void) {
     ship_type *stype;
 
     config_set("movement.shipspeed.skillbonus", "0");
-    r = test_create_region(0, 0, test_create_terrain("ocean", 0));
+    r = test_create_ocean(0, 0);
     stype = test_create_shiptype("longboat");
     stype->cptskill = 1;
     stype->sumskill = 10;
diff --git a/src/kernel/unit.test.c b/src/kernel/unit.test.c
index 19cfe731d..9391e7012 100644
--- a/src/kernel/unit.test.c
+++ b/src/kernel/unit.test.c
@@ -304,7 +304,7 @@ static void test_inside_building(CuTest *tc) {
 
     test_setup();
     u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
-    b = test_create_building(u->region, 0);
+    b = test_create_building(u->region, NULL);
 
     b->size = 1;
     scale_number(u, 1);
@@ -395,7 +395,7 @@ static void test_unit_description(CuTest *tc) {
     test_setup();
     lang = test_create_locale();
     rc = test_create_race("hodor");
-    u = test_create_unit(test_create_faction(rc), test_create_region(0,0,0));
+    u = test_create_unit(test_create_faction(rc), test_create_region(0, 0, NULL));
 
     CuAssertPtrEquals(tc, 0, u->display);
     CuAssertStrEquals(tc, 0, u_description(u, lang));
diff --git a/src/laws.test.c b/src/laws.test.c
index 795c46f16..5edde187d 100644
--- a/src/laws.test.c
+++ b/src/laws.test.c
@@ -955,7 +955,7 @@ static void test_name_building(CuTest *tc) {
     faction *f;
 
     u = setup_name_cmd();
-    u->building = test_create_building(u->region, 0);
+    u->building = test_create_building(u->region, NULL);
     f = u->faction;
     uo = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
     u_set_building(uo, u->building);
@@ -999,7 +999,7 @@ static void test_name_ship(CuTest *tc) {
     faction *f;
 
     u = setup_name_cmd();
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     f = u->faction;
     uo = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
     u_set_ship(uo, u->ship);
@@ -1206,13 +1206,13 @@ static void test_name_cmd(CuTest *tc) {
     free_order(ord);
 
     ord = create_order(K_NAME, f->locale, "%s '  Ho\tdor  '", LOC(f->locale, parameters[P_SHIP]));
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     name_cmd(u, ord);
     CuAssertStrEquals(tc, "Hodor", u->ship->name);
     free_order(ord);
     
     ord = create_order(K_NAME, f->locale, "%s '  Ho\tdor  '", LOC(f->locale, parameters[P_BUILDING]));
-    u_set_building(u, test_create_building(u->region, 0));
+    u_set_building(u, test_create_building(u->region, NULL));
     name_cmd(u, ord);
     CuAssertStrEquals(tc, "Hodor", u->building->name);
     free_order(ord);
diff --git a/src/move.test.c b/src/move.test.c
index 201374e11..3aca0c2ab 100644
--- a/src/move.test.c
+++ b/src/move.test.c
@@ -75,7 +75,7 @@ static void setup_harbor(move_fixture *mf) {
     ttype = test_create_terrain("glacier", LAND_REGION | ARCTIC_REGION | WALK_INTO);
     btype = test_create_buildingtype("harbour");
 
-    sh = test_create_ship(0, 0);
+    sh = test_create_ship(0, NULL);
     r = test_create_region(0, 0, ttype);
 
     b = test_create_building(r, btype);
@@ -219,8 +219,8 @@ static void test_ship_trails(CuTest *tc) {
     r1 = test_create_region(0, 0, otype);
     r2 = test_create_region(1, 0, otype);
     r3 = test_create_region(2, 0, otype);
-    sh = test_create_ship(r1, 0);
-    move_ship(sh, r1, r3, 0);
+    sh = test_create_ship(r1, NULL);
+    move_ship(sh, r1, r3, NULL);
     CuAssertPtrEquals(tc, r3, sh->region);
     CuAssertPtrEquals(tc, sh, r3->ships);
     CuAssertPtrEquals(tc, 0, r1->ships);
@@ -246,8 +246,8 @@ static void test_age_trails(CuTest *tc) {
 
     test_setup();
     r1 = test_create_region(0, 0, NULL);
-    r2 = test_create_region(1, 0, 0);
-    sh = test_create_ship(r1, 0);
+    r2 = test_create_region(1, 0, NULL);
+    sh = test_create_ship(r1, NULL);
     add_regionlist(&route, r1);
     add_regionlist(&route, r2);
     move_ship(sh, r1, r2, route);
diff --git a/src/renumber.test.c b/src/renumber.test.c
index d205b6dc7..dfac52e8c 100644
--- a/src/renumber.test.c
+++ b/src/renumber.test.c
@@ -58,7 +58,7 @@ static void test_renumber_building(CuTest *tc) {
 
     test_setup_ex(tc);
     u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
-    u->building = test_create_building(u->region, 0);
+    u->building = test_create_building(u->region, NULL);
     no = u->building->no;
     uno = (no > 1) ? no - 1 : no + 1;
     lang = u->faction->locale;
@@ -76,9 +76,9 @@ static void test_renumber_building_duplicate(CuTest *tc) {
 
     test_setup_ex(tc);
     u = test_create_unit(f = test_create_faction(NULL), test_create_region(0, 0, NULL));
-    u->building = test_create_building(u->region, 0);
+    u->building = test_create_building(u->region, NULL);
     uno = u->building->no;
-    u->building = test_create_building(u->region, 0);
+    u->building = test_create_building(u->region, NULL);
     no = u->building->no;
     lang = f->locale;
     u->thisorder = create_order(K_NUMBER, lang, "%s %s", LOC(lang, parameters[P_BUILDING]), itoa36(uno));
@@ -95,7 +95,7 @@ static void test_renumber_ship(CuTest *tc) {
 
     test_setup_ex(tc);
     u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     no = u->ship->no;
     uno = (no > 1) ? no - 1 : no + 1;
     lang = u->faction->locale;
@@ -112,7 +112,7 @@ static void test_renumber_ship_twice(CuTest *tc) {
 
     test_setup_ex(tc);
     u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     no = u->ship->no;
     uno = (no > 1) ? no - 1 : no + 1;
     lang = u->faction->locale;
@@ -134,9 +134,9 @@ static void test_renumber_ship_duplicate(CuTest *tc) {
 
     test_setup_ex(tc);
     u = test_create_unit(f = test_create_faction(NULL), test_create_region(0, 0, NULL));
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     uno = u->ship->no;
-    u->ship = test_create_ship(u->region, 0);
+    u->ship = test_create_ship(u->region, NULL);
     no = u->ship->no;
     lang = f->locale;
     u->thisorder = create_order(K_NUMBER, lang, "%s %s", LOC(lang, parameters[P_SHIP]), itoa36(uno));
diff --git a/src/report.test.c b/src/report.test.c
index dfb3b59de..77bb6dca6 100644
--- a/src/report.test.c
+++ b/src/report.test.c
@@ -159,7 +159,7 @@ static void test_report_travelthru(CuTest *tc) {
     r->flags |= RF_TRAVELUNIT;
     f = test_create_faction(NULL);
     f->locale = lang;
-    u = test_create_unit(f, test_create_region(0, 1, 0));
+    u = test_create_unit(f, test_create_region(0, 1, NULL));
     unit_setname(u, "Hodor");
     unit_setid(u, 1);
 
diff --git a/src/travelthru.test.c b/src/travelthru.test.c
index 89ea3e728..8a38891b1 100644
--- a/src/travelthru.test.c
+++ b/src/travelthru.test.c
@@ -35,7 +35,7 @@ static void setup_travelthru(travel_fixture *fix, int nunits) {
     }
     f = test_create_faction(NULL);
     while (nunits--) {
-        unit *u = test_create_unit(f, test_create_region(1, 0, 0));
+        unit *u = test_create_unit(f, test_create_region(1, 0, NULL));
         travelthru_add(r, u);
     }
     fix->r = r;