Added unit tests for Java, JavaScript and JSON mods

tests/src/test/java/ModTestExotic.java

@@ -0,0 +1,40 @@
+import arc.util.*;
+import mindustry.*;
+import mindustry.gen.*;
+import mindustry.type.*;
+import org.junit.jupiter.api.*;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+//grabs a version-locked exotic-mod commit and makes sure its content is parsed correctly
+//this mod was chosen because:
+//- it is written solely in (h)json
+//- it is probably the mod with the most json, and as such covers a lot of classes
+//- it is popular enough in the mod browser
+//- I am somewhat familiar with its files & the type of content it adds
+public class ModTestExotic extends GenericModTest{
+
+    @Test
+    public void begin(){
+        grabMod("https://github.com/BlueWolf3682/Exotic-Mod/archive/08c861398ac9c3d1292132f9a110e17e06294a90.zip");
+        checkExistence("exotic-mod");
+
+        UnitType type = Vars.content.units().find(u -> u.name.equals("exotic-mod-luminance"));
+        assertNotNull(type, "A mod unit must be loaded.");
+        assertTrue(type.weapons.size > 0, "A mod unit must have a weapon.");
+
+        Vars.world.loadMap(ApplicationTests.testMap);
+
+        Unit unit = type.spawn(0, 0);
+
+        //check for crash
+        unit.update();
+
+        assertTrue(unit.health > 0, "Unit must be spawned and alive.");
+        assertTrue(Groups.unit.size() > 0, "Unit must be spawned and alive.");
+
+        //just an extra sanity check
+        Log.info("Modded units: @", Vars.content.units().select(u -> u.minfo.mod != null));
+    }
+
+}