Added unit tests for Java, JavaScript and JSON mods

tests/src/test/java/ModTestBM.java

@@ -0,0 +1,39 @@
+import mindustry.*;
+import mindustry.world.*;
+import mindustry.world.meta.*;
+import org.junit.jupiter.api.*;
+
+import static mindustry.Vars.*;
+import static org.junit.jupiter.api.Assertions.*;
+
+//grabs a betamindy release and makes sure it initializes correctly
+//this mod was chosen because:
+//- it is one of the top java mods on the browser
+//- it uses a variety of mindustry classes
+//- it is popular enough to cause significant amounts of crashes when something breaks
+//- I have some familiarity with its codebase
+public class ModTestBM extends GenericModTest{
+
+    @Test
+    public void begin(){
+        grabMod("https://github.com/sk7725/BetaMindy/releases/download/v0.955/BetaMindy.jar");
+
+        checkExistence("betamindy");
+
+        Block type = Vars.content.blocks().find(u -> u.name.equals("betamindy-piston"));
+        assertNotNull(type, "A mod block must be loaded.");
+        assertSame(type.buildVisibility, BuildVisibility.shown, "A mod block must be buildable.");
+
+        world.loadMap(ApplicationTests.testMap);
+        Tile t = world.tile(3, 3);
+
+        t.setBlock(type);
+
+        //check for crash
+        t.build.update();
+
+        assertTrue(t.build.health > 0, "Block must be spawned and alive.");
+        assertSame(t.build.block, type, "Block must be spawned and alive.");
+    }
+
+}