Fix Entity.name / symbol not returning null, add tests

src/entity.zig

@@ -227,7 +227,7 @@ pub fn Entity(comptime ctx: anytype) type {
         /// the entity is alive and its name doesn't change.
         pub fn name(self: Self) ?[:0]const u8 {
             const result = c.ecs_get_name(self.world.raw, self.raw);
-            return std.mem.sliceTo(result, 0);
+            return if (result != 0) std.mem.sliceTo(result, 0) else null;
         }
 
         /// Sets the name of this `Entity` to the specified value, if any.
@@ -243,7 +243,7 @@ pub fn Entity(comptime ctx: anytype) type {
         /// the entity is alive and its symbol doesn't change.
         pub fn symbol(self: Self) ?[:0]const u8 {
             const result = c.ecs_get_symbol(self.world.raw, self.raw);
-            return std.mem.sliceTo(result, 0);
+            return if (result != 0) std.mem.sliceTo(result, 0) else null;
         }
 
         /// Sets the symbol of this `Entity` to the specified value, if any.
@@ -375,6 +375,35 @@ pub fn Entity(comptime ctx: anytype) type {
 const expect = @import("./test/expect.zig");
 const flecszigble = @import("./main.zig");
 
+test "Entity with name and symbol" {
+    flecszigble.init(std.testing.allocator);
+    var world = try flecszigble.World(void).initMinimal();
+    defer world.deinit();
+
+    const entity = try world.entity(.{ .name = "name", .symbol = "symbol" }, .{});
+
+    try expect.equalStrings("name", entity.name());
+    try expect.equalStrings("symbol", entity.symbol());
+
+    try expect.equal(entity, world.lookupChild(null, "name"));
+    try expect.equal(entity, world.lookupSymbol("symbol"));
+}
+
+test "Entity get and set name" {
+    flecszigble.init(std.testing.allocator);
+    var world = try flecszigble.World(void).initMinimal();
+    defer world.deinit();
+
+    const entity = try world.entity(.{}, .{});
+    try expect.equal(null, entity.name());
+
+    entity.setName("hello");
+    try expect.equalStrings("hello", entity.name());
+
+    entity.setName(null);
+    try expect.equal(null, entity.name());
+}
+
 test "Entity get and set" {
     flecszigble.init(std.testing.allocator);
     var world = try flecszigble.World(void).initMinimal();
@@ -472,4 +501,9 @@ test "Entity format" {
     try expect.fmt("/grandparent", "{unix}", .{grandparent});
     try expect.fmt("/grandparent/parent", "{unix}", .{parent});
     try expect.fmt("/grandparent/parent/child", "{unix}", .{child});
+
+    parent.setName(null);
+    try expect.fmt("411", "{s}", .{parent});
+    try expect.fmt("/grandparent/411", "{unix}", .{parent});
+    try expect.fmt("/grandparent/411/child", "{unix}", .{child});
 }