Implemented a few basic tests and ideas for future ones

src/infrastructure/node_manager.zig

@@ -73,4 +73,32 @@ pub const NodeManager = struct {
         self.nodes.clearRetainingCapacity();
         self.next_id = 0;
     }
-};
+};
+
+const expect = std.testing.expect;
+
+test "id tracking" {
+    var gpa: std.heap.DebugAllocator(.{}) = .init;
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+
+    var node_man: NodeManager = .init();
+    defer node_man.deinit(allocator);
+    const n = 5;
+
+    for (0..n) |_| {
+        const node: Node = .init(node_man.getNextID(), Vector2 {
+            .x = 500,
+            .y = 500,
+        });
+        const node_ptr = try allocator.create(Node);
+        node_ptr.* = node;
+        try node_man.nodes.append(allocator, node_ptr);
+    }
+
+    try expect(node_man.next_id == n);
+    try expect(node_man.nodes.items.len == n);
+}
+
+// TODO tests
+// force resize pointer test