Unit tests to evaluate behavior with max_experience=0 and with no advancements (#7344)

data/test/scenarios/wml_tests/UnitsWML/unit_no_advancements.cfg

@@ -0,0 +1,66 @@
+# wmllint: no translatables
+
+#####
+# API(s) being tested: [unit][advancement]
+##
+# Actions:
+# Harm Alice and Bob with 1 hitpoint to be sure that they have some damage. Delete advancements of both units and give them 999 experience. They then fight each other.
+##
+# Expected end state:
+# Bob and Alice doesn't level up, keeps their HP, and gains experience. The default behaviour should be that a unit will never advances if it has no advancements, but still can gain experience internally (seen with inspect console).
+#####
+{COMMON_KEEP_A_B_UNIT_TEST "unit_no_advancements" (
+    [event]
+        name=prestart
+        [harm_unit]
+            [filter]
+                id=bob,alice
+            [/filter]
+            amount=1
+        [/harm_unit]
+        [modify_unit]
+            [filter]
+                id=alice,bob
+            [/filter]
+            [object]
+                [effect]
+                    apply_to=remove_advancement
+                    types=Orcish Warrior,Elvish Ranger,Elvish Marksman
+                [/effect]
+            [/object]
+            experience=999
+        [/modify_unit]
+    [/event]
+    [event]
+        name=start
+        [do_command]
+            [attack]
+                weapon=0
+                defender_weapon=0
+                [source]
+                    x,y=5,3
+                [/source]
+                [destination]
+                    x,y=4,3
+                [/destination]
+            [/attack]
+        [/do_command]
+        [store_unit]
+            [filter]
+                id=alice
+            [/filter]
+            variable=alice
+        [/store_unit]
+        [store_unit]
+            [filter]
+                id=bob
+            [/filter]
+            variable=bob
+        [/store_unit]
+        {ASSERT ({VARIABLE_CONDITIONAL bob.hitpoints less_than $bob.max_hitpoints})}
+        {ASSERT ({VARIABLE_CONDITIONAL alice.hitpoints less_than $alice.max_hitpoints})}
+        {ASSERT ({VARIABLE_CONDITIONAL bob.experience greater_than 999})}
+        {ASSERT ({VARIABLE_CONDITIONAL alice.experience greater_than 999})}
+        {SUCCEED}
+    [/event]
+)}

data/test/scenarios/wml_tests/UnitsWML/zero_experience.cfg

@@ -0,0 +1,88 @@
+# wmllint: no translatables
+
+#####
+# API(s) being tested: [unit]max_experience=0
+##
+# Actions:
+# Try to set Alice's and Bob's max_experience to 0 and check that the engine applies a minimum of 1. Delete Bob's 'Orcish Warrior' advancement but not Alice's. Harm bob with 1 hitpoint to be sure that he have some damage. They then fight each other.
+##
+# Expected end state:
+# Alice levels up and changes his max_experience to the advancement. Bob don't advances and have 1 point of max experience. The default behaviour is for a unit with max_experience 0 always changes to 1, no matter if they have advancements or not (seen with inspect console).
+#####
+{COMMON_KEEP_A_B_UNIT_TEST "zero_experience" (
+    [event]
+        name=prestart
+        [modify_unit]
+            [filter]
+                id=alice,bob
+            [/filter]
+            [effect]
+                apply_to=max_experience
+                set=0
+            [/effect]
+        [/modify_unit]
+        [modify_unit]
+            [filter]
+                id=alice,bob
+            [/filter]
+            [object]
+                [effect]
+                    apply_to=remove_advancement
+                    types=Orcish Warrior
+                [/effect]
+            [/object]
+        [/modify_unit]
+        [harm_unit]
+            [filter]
+                id=bob,alice
+            [/filter]
+            amount=1
+        [/harm_unit]
+        [store_unit]
+            [filter]
+                id=alice
+            [/filter]
+            variable=pre_alice
+        [/store_unit]
+        [store_unit]
+            [filter]
+                id=bob
+            [/filter]
+            variable=pre_bob
+        [/store_unit]
+    [/event]
+    [event]
+        name=start
+        [do_command]
+            [attack]
+                weapon=0
+                defender_weapon=0
+                [source]
+                    x,y=5,3
+                [/source]
+                [destination]
+                    x,y=4,3
+                [/destination]
+            [/attack]
+        [/do_command]
+        [store_unit]
+            [filter]
+                id=alice
+            [/filter]
+            variable=alice
+        [/store_unit]
+        [store_unit]
+            [filter]
+                id=bob
+            [/filter]
+            variable=bob
+        [/store_unit]
+        {ASSERT ({VARIABLE_CONDITIONAL pre_bob.max_experience numerical_equals 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL pre_alice.max_experience numerical_equals 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL bob.max_experience numerical_equals 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL alice.max_experience greater_than 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL bob.level numerical_equals 1})}
+        {ASSERT ({VARIABLE_CONDITIONAL alice.level numerical_equals 2})}
+        {SUCCEED}
+    [/event]
+)}

wml_test_schedule

@@ -430,6 +430,8 @@
 0 kill_fires_events
 # Game mechanics
 0 heal
+0 zero_experience
+0 unit_no_advancements
 # Warnings about WML
 0 unknown_scenario_false_positives
 0 unknown_scenario_interpolated