Add first Entity tests

src/c.zig

@@ -4,5 +4,8 @@ pub usingnamespace @cImport({
     if (@import("builtin").mode == .Debug)
         @cDefine("FLECS_SANITIZE", {});
 
+    // Flecs' default NULL macro causes issues.
+    @cDefine("NULL", "0");
+
     @cInclude("flecs.h");
 });

test/entity.zig

@@ -0,0 +1,40 @@
+// Reimplementations of the following tests from Flecs:
+// https://github.com/SanderMertens/flecs/blob/master/test/api/src/Entity.c
+
+const std = @import("std");
+const expect = std.testing.expect;
+const expectEql = std.testing.expectEqual;
+const expectStrEql = std.testing.expectEqualStrings;
+
+const util = @import("./util.zig");
+
+const flecs = @import("../src/main.zig");
+const c = flecs.c;
+
+const context = flecs.Context(void);
+const World = context.World;
+const Entity = context.Entity;
+
+test "Entity_init_id" {
+    var world = try World.initMinimal(std.testing.allocator);
+    defer world.deinit();
+
+    const e = try world.entity(.{}, .{});
+    // try expect(e.raw != 0); -- Not necessary, world.entity() returns error if result would be 0.
+    try expect(c.ecs_get_type(world.raw, e.raw) == null);
+}
+
+test "Entity_init_id_name" {
+    var world = try World.initMinimal(std.testing.allocator);
+    defer world.deinit();
+
+    const e = try world.entity(.{ .name = "foo" }, .{});
+    // try expect(e.raw != 0); -- Not necessary, world.entity() returns error if result would be 0.
+    try expectStrEql("foo", e.getName().?);
+
+    // TODO: Implement EntityPath.
+    const path = c.ecs_get_fullpath(world.raw, e.raw);
+    defer c.ecs_os_api.free_.?(path);
+    try expect(path != null);
+    try expectStrEql("foo", std.mem.sliceTo(path.?, 0));
+}

test/main.zig

@@ -1,4 +1,5 @@
 test {
     _ = @import("../src/main.zig");
+    _ = @import("./entity.zig");
     _ = @import("./world.zig");
 }