Test weapon-special plague vs taught plague

The expectation is that the a unit's own weapon special will take
priority over a teacher's ability.

data/test/scenarios/wml_tests/UnitsWML/AbilitiesWML/plague_without_priority.cfg

@@ -0,0 +1,170 @@
+#textdomain wesnoth-test
+
+#####
+# API(s) being tested: [specials][plague],[abilities][plague]affect_allies=yes
+##
+# Actions:
+# This uses a "common keep" map, with Alice and Bob already adjacent to the other units.
+# Give Bob a plague weapon special that creates Blood Bats.
+# Make Charlie teach a plague ability that creates Chocobones.
+# Make Dave teach a plague ability that creates Dragonguards.
+# Create targets around Alice and Bob.
+# Have Alice and Bob kill 1 target each.
+# Remove Charlie and Dave.
+# Have Alice and Bob kill 1 target each.
+##
+# Expected end state:
+# Alice's attacks created 1 unit of a type taught by Charlie or Dave.
+# Bob's own weapon special had priority over Charlie and Dave's teaching ability.
+# Bob's attacks created 2 Blood Bats.
+#####
+{COMMON_KEEP_A_B_C_D_UNIT_TEST plague_without_priority (
+    [event]
+        name=start
+
+        [object]
+            [filter]
+                id=bob
+            [/filter]
+            [effect]
+                apply_to=attack
+                [set_specials]
+                    mode=append
+                    {WEAPON_SPECIAL_PLAGUE_TYPE (Blood Bat)}
+                [/set_specials]
+            [/effect]
+        [/object]
+
+        [object]
+            [filter]
+                id=charlie
+            [/filter]
+            [effect]
+                apply_to=new_ability
+                [abilities]
+                    {WEAPON_SPECIAL_PLAGUE_TYPE Chocobone}
+                    [+plague]
+                        affect_self=yes
+                        affect_allies=yes
+                        affect_enemies=yes
+                        [affect_adjacent]
+                        [/affect_adjacent]
+                    [/plague]
+                [/abilities]
+            [/effect]
+        [/object]
+
+        [object]
+            [filter]
+                id=dave
+            [/filter]
+            [effect]
+                apply_to=new_ability
+                [abilities]
+                    {WEAPON_SPECIAL_PLAGUE_TYPE (Dwarvish Dragonguard)}
+                    [+plague]
+                        [filter_student]
+                        [/filter_student]
+                        affect_self=yes
+                        affect_allies=yes
+                        affect_enemies=yes
+                        [affect_adjacent]
+                        [/affect_adjacent]
+                    [/plague]
+                [/abilities]
+            [/effect]
+        [/object]
+
+        # Create some targets
+        [for]
+            start=1
+            end=2
+            [do]
+                [unit]
+                    location_id=1
+                    id=target_for_alice_$i
+                    type=Test Melee Quintain
+                    side=2
+                    hitpoints=1
+                [/unit]
+                [unit]
+                    location_id=2
+                    id=target_for_bob_$i
+                    type=Test Melee Quintain
+                    side=1
+                    hitpoints=1
+                [/unit]
+            [/do]
+        [/for]
+
+        # With Charlie and Dave teaching plague
+        # The test isn't checking priority between Charlie and Dave, just that one of the teaching abilities takes effect,
+        # however it needs 2 teachers to check that Bob's weapon special takes priority over both left and right.
+        [test_do_attack_by_id]
+            attacker=alice
+            defender=target_for_alice_1
+            weapon=0
+        [/test_do_attack_by_id]
+        [test_do_attack_by_id]
+            attacker=bob
+            defender=target_for_bob_1
+            weapon=0
+        [/test_do_attack_by_id]
+
+        {ASSERT (
+            [have_unit]
+                type=Blood Bat
+                count=1
+            [/have_unit]
+        )}
+        {ASSERT (
+            [have_unit]
+                type=Chocobone,Dwarvish Dragonguard
+                count=1
+            [/have_unit]
+        )}
+
+        # With neither Charlie nor Dave
+        [store_unit]
+            [filter]
+                id=charlie
+            [/filter]
+            variable=stored_charlie
+            kill=yes
+        [/store_unit]
+        [store_unit]
+            [filter]
+                id=dave
+            [/filter]
+            variable=stored_dave
+            kill=yes
+        [/store_unit]
+        [test_do_attack_by_id]
+            attacker=alice
+            defender=target_for_alice_2
+            weapon=0
+            resupply_attacks_left=1
+        [/test_do_attack_by_id]
+        [test_do_attack_by_id]
+            attacker=bob
+            defender=target_for_bob_2
+            weapon=0
+            resupply_attacks_left=1
+        [/test_do_attack_by_id]
+
+        {ASSERT (
+            [have_unit]
+                type=Blood Bat
+                count=2
+            [/have_unit]
+        )}
+        {ASSERT (
+            [have_unit]
+                type=Chocobone,Dwarvish Dragonguard
+                count=1
+            [/have_unit]
+        )}
+
+        {SUCCEED}
+    [/event]
+)}

wml_test_schedule

@@ -335,6 +335,7 @@
 0 effect_increase_attacks
 0 opponent_weapon_has_no_special
 0 opponent_weapon_has_special
+0 plague_without_priority
 0 student_teacher_are_same
 # Math operations in ability or specials tags
 0 special_calculation_add