diff --git a/src/kernel/item.test.c b/src/kernel/item.test.c
index 47b32b537..231b45d00 100644
--- a/src/kernel/item.test.c
+++ b/src/kernel/item.test.c
@@ -74,7 +74,7 @@ void test_change_item(CuTest * tc)
     test_create_itemtype("iron");
     init_resources();
 
-    u = test_create_unit(test_create_faction(0), 0);
+    u = test_create_unit(test_create_faction(0), test_create_region(0, 0, 0));
     test_uchange(tc, u, get_resourcetype(R_IRON));
     test_cleanup();
 }
diff --git a/src/reports.test.c b/src/reports.test.c
index f368e63e1..c27a0f6f9 100644
--- a/src/reports.test.c
+++ b/src/reports.test.c
@@ -220,7 +220,7 @@ static void test_write_travelthru(CuTest *tc) {
     r->flags |= RF_TRAVELUNIT;
     f = test_create_faction(0);
     f->locale = lang;
-    u = test_create_unit(f, 0);
+    u = test_create_unit(f, test_create_region(0, 1, 0));
     unit_setname(u, "Hodor");
     unit_setid(u, 1);
 
diff --git a/src/study.test.c b/src/study.test.c
index f12fc25df..0ecd7ae2e 100644
--- a/src/study.test.c
+++ b/src/study.test.c
@@ -295,7 +295,7 @@ static void test_demon_skillchanges(CuTest *tc) {
     test_setup();
     rc = test_create_race("demon");
     CuAssertPtrEquals(tc, rc, get_race(RC_DAEMON));
-    u = test_create_unit(test_create_faction(rc), 0);
+    u = test_create_unit(test_create_faction(rc), test_create_region(0, 0, 0));
     CuAssertPtrNotNull(tc, u);
     set_level(u, SK_CROSSBOW, 1);
     demon_skillchange(u);
diff --git a/src/tests.c b/src/tests.c
index 13400ebd4..b9336bb25 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -119,7 +119,7 @@ struct faction *test_create_faction(const struct race *rc)
 struct unit *test_create_unit(struct faction *f, struct region *r)
 {
     const struct race * rc = f ? f->race : 0;
-    assert(f || !r);
+    assert(f && r);
     if (!rc) rc = rc_get_or_create("human");
     return create_unit(r, f, 1, rc ? rc : rc_get_or_create("human"), 0, 0, 0);
 }