diff --git a/critbit b/critbit
index 934c2dd94..ee7a32b9b 160000
--- a/critbit
+++ b/critbit
@@ -1 +1 @@
-Subproject commit 934c2dd94d41da19637a76a1a8b3dfeb7aa8524d
+Subproject commit ee7a32b9b8986bf2ea6b287975f9ef0ec997b7a3
diff --git a/src/kernel/equipment.test.c b/src/kernel/equipment.test.c
index 851e591d2..f0543ad8c 100644
--- a/src/kernel/equipment.test.c
+++ b/src/kernel/equipment.test.c
@@ -36,7 +36,7 @@ void test_equipment(CuTest * tc)
     equipment_setskill(eq, SK_MAGIC, "5");
     equipment_addspell(eq, sp, 1);
 
-    u = test_create_unit(0, 0);
+    u = test_create_unit(test_create_faction(0), 0);
     equip_unit_mask(u, eq, EQUIP_ALL);
     CuAssertIntEquals(tc, 1, i_get(u->items, it_horses));
     CuAssertIntEquals(tc, 5, get_level(u, SK_MAGIC));
diff --git a/src/kernel/item.test.c b/src/kernel/item.test.c
index 2d76422ff..1c133b74f 100644
--- a/src/kernel/item.test.c
+++ b/src/kernel/item.test.c
@@ -64,7 +64,7 @@ void test_change_item(CuTest * tc)
     test_create_itemtype("iron");
     init_resources();
 
-    u = test_create_unit(0, 0);
+    u = test_create_unit(test_create_faction(0), 0);
     test_uchange(tc, u, get_resourcetype(R_IRON));
 }
 
diff --git a/src/randenc.c b/src/randenc.c
index a7227a210..dfa1e998d 100644
--- a/src/randenc.c
+++ b/src/randenc.c
@@ -958,38 +958,7 @@ static void demon_skillchanges(void)
         unit *u;
         for (u = r->units; u; u = u->next) {
             if (u_race(u) == get_race(RC_DAEMON)) {
-                skill *sv = u->skills;
-                int upchance = 15;
-                int downchance = 10;
-
-                if (fval(u, UFL_HUNGER)) {
-                    /* hungry demons only go down, never up in skill */
-                    int rule_hunger = config_get_int("hunger.demons.skill", 0) != 0;
-                    if (rule_hunger) {
-                        upchance = 0;
-                        downchance = 15;
-                    }
-                }
-
-                while (sv != u->skills + u->skill_size) {
-                    int roll = rng_int() % 100;
-                    if (sv->level > 0 && roll < upchance + downchance) {
-                        int weeks = 1 + rng_int() % 3;
-                        if (roll < downchance) {
-                            reduce_skill(u, sv, weeks);
-                            if (sv->level < 1) {
-                                /* demons should never forget below 1 */
-                                set_level(u, sv->id, 1);
-                            }
-                        }
-                        else {
-                            while (weeks--) {
-                                learn_skill_depr(u, sv->id, 1.0);
-                            }
-                        }
-                    }
-                    ++sv;
-                }
+                demon_skillchange(u);
             }
         }
     }
diff --git a/src/study.c b/src/study.c
index 0cb8df525..a39f2e57b 100644
--- a/src/study.c
+++ b/src/study.c
@@ -826,7 +826,7 @@ bool learn_skill_depr(unit * u, skill_t sk, double learn_chance)
     }
 #endif
     if (learn_chance < 1.0 && rng_int() % 10000 >= learn_chance * 10000)
-        if (!chance(learn_chance))
+        if (!chance(learn_chance)) // FIXME: this nested if looks as if we are rolling twice!
             return false;
     while (sv != u->skills + u->skill_size) {
         assert(sv->weeks > 0);
@@ -865,3 +865,39 @@ void learn_skill(unit *u, skill_t sk, int days) {
     }
     sv->weeks -= weeks;
 }
+
+/** Talente von Dämonen verschieben sich.
+*/
+void demon_skillchange(unit *u)
+{
+    skill *sv = u->skills;
+    int upchance = 15;
+    int downchance = 10;
+
+    if (fval(u, UFL_HUNGER)) {
+        /* hungry demons only go down, never up in skill */
+        int rule_hunger = config_get_int("hunger.demon.skill", 0) != 0;
+        if (rule_hunger) {
+            upchance = 0;
+            downchance = 15;
+        }
+    }
+
+    while (sv != u->skills + u->skill_size) {
+        int roll = rng_int() % 100;
+        if (sv->level > 0 && roll < upchance + downchance) {
+            int weeks = 1 + rng_int() % 3;
+            if (roll < downchance) {
+                reduce_skill(u, sv, weeks);
+                if (sv->level < 1) {
+                    /* demons should never forget below 1 */
+                    set_level(u, sv->id, 1);
+                }
+            }
+            else {
+                learn_skill(u, sv->id, STUDYDAYS*weeks);
+            }
+        }
+        ++sv;
+    }
+}
diff --git a/src/study.h b/src/study.h
index 52c384aba..078204a6e 100644
--- a/src/study.h
+++ b/src/study.h
@@ -47,6 +47,8 @@ extern "C" {
     void produceexp(struct unit *u, skill_t sk, int n);
     void produceexp_ex(struct unit *u, skill_t sk, int n, bool(*learn)(struct unit *, skill_t, double));
 
+    void demon_skillchange(struct unit *u);
+
 #define MAXTEACHERS 20
 #define TEACHNUMBER 10
     typedef struct teaching_info {
diff --git a/src/study.test.c b/src/study.test.c
index b51e17e68..64db05e26 100644
--- a/src/study.test.c
+++ b/src/study.test.c
@@ -3,12 +3,13 @@
 #include "study.h"
 
 #include <kernel/config.h>
-#include <kernel/unit.h>
+#include <kernel/building.h>
 #include <kernel/faction.h>
 #include <kernel/item.h>
 #include <kernel/order.h>
+#include <kernel/race.h>
 #include <kernel/region.h>
-#include <kernel/building.h>
+#include <kernel/unit.h>
 #include <util/rand.h>
 #include <util/message.h>
 #include <util/language.h>
@@ -247,6 +248,19 @@ void test_learn_skill(CuTest *tc) {
     test_cleanup();
 }
 
+void test_demon_skillchanges(CuTest *tc) {
+    unit * u;
+    race * rc;
+    test_cleanup();
+    rc = test_create_race("demon");
+    CuAssertPtrEquals(tc, rc, get_race(RC_DAEMON));
+    u = test_create_unit(test_create_faction(rc), 0);
+    CuAssertPtrNotNull(tc, u);
+    set_level(u, SK_CROSSBOW, 1);
+    demon_skillchange(u);
+    test_cleanup();
+}
+
 CuSuite *get_study_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
@@ -256,6 +270,7 @@ CuSuite *get_study_suite(void)
     SUITE_ADD_TEST(suite, test_study_with_bad_teacher);
     SUITE_ADD_TEST(suite, test_produceexp);
     SUITE_ADD_TEST(suite, test_academy_building);
+    SUITE_ADD_TEST(suite, test_demon_skillchanges);
     DISABLE_TEST(suite, test_study_bug_2194);
     return suite;
 }
diff --git a/src/tests.c b/src/tests.c
index f8a0c2a7f..c03680baf 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -77,8 +77,9 @@ 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);
-    return create_unit(r, f, 1, rc ? rc : rc_get_or_create("human"), 0, 0, 0);
+    assert(f);
+    if (!rc) rc = rc_get_or_create("human");
+    return create_unit(r, f, 1, rc, 0, 0, 0);
 }
 
 void test_cleanup(void)