started the level.dat file creation and completion... I may need to continue the code of level.rs and make an update function to level.dat

src/test.rs

@@ -0,0 +1,78 @@
+/// Test for perlin.rs
+#[cfg(test)]
+mod perlin_test {
+    use crate::perlin::{CHUNK_SIZE, MAX_Y, MIN_Y, generate_height_chunk};
+
+    use image::{ImageBuffer, Luma};
+
+    #[test]
+    #[ignore]
+    fn dump_chunk_png() {
+        let seed: u64 = 42;
+        let chunks_x: usize = 32;
+        let chunks_z: usize = 32;
+
+        let w: u32 = (chunks_x * CHUNK_SIZE) as u32;
+        let h: u32 = (chunks_z * CHUNK_SIZE) as u32;
+
+        let mut field = vec![0i32; (w as usize) * (h as usize)];
+
+        for cz in 0..chunks_z {
+            for cx in 0..chunks_x {
+                let tile = generate_height_chunk(seed, cx as i32, cz as i32);
+                for lz in 0..CHUNK_SIZE {
+                    for lx in 0..CHUNK_SIZE {
+                        let x = cx * CHUNK_SIZE + lx;
+                        let z = cz * CHUNK_SIZE + lz;
+                        field[z * (w as usize) + x] = tile[lx][lz];
+                    }
+                }
+            }
+        }
+
+        let mut img: ImageBuffer<Luma<u16>, Vec<u16>> = ImageBuffer::new(w, h);
+        let denom = (MAX_Y - MIN_Y) as f32;
+        for z in 0..h {
+            for x in 0..w {
+                let v = field[(z as usize) * (w as usize) + (x as usize)];
+                let n01 = ((v - MIN_Y) as f32 / denom).clamp(0.0, 1.0);
+                let p = (n01 * u16::MAX as f32).round() as u16;
+                img.put_pixel(x, z, Luma([p]));
+            }
+        }
+
+        std::fs::create_dir_all("target").ok();
+        img.save("target/heightmap16.png").unwrap();
+    }
+}
+/// Test for level.rs
+#[cfg(test)]
+mod level_file_test {
+    use crate::level::create_nbt;
+    #[test]
+    fn test_creation_of_file() -> () {
+        let result = create_nbt(
+            "test".to_string(),
+            1234,
+            true,
+            true,
+            true,
+            true,
+            1,
+            1,
+            1,
+            0,
+            0,
+            0,
+            213,
+            1235,
+            55555,
+            90000,
+            900,
+            "test".to_string(),
+            "test".to_string(),
+            "target/level.dat".to_string(),
+        );
+        assert_eq!(result.is_ok(), true);
+    }
+}