diff --git a/DESCRIPTION b/DESCRIPTION
index 12987cab..65f2c240 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,5 +1,5 @@
 Package: dymiumCore
-Version: 0.1.9.9000
+Version: 0.1.9.9002
 Title: A Toolkit for Building a Dynamic Microsimulation Model for Integrated Urban Modelling
 Description: A modular microsimulation modelling framework for integrated urban modelling.
 Authors@R: c(
@@ -32,7 +32,7 @@ Imports:
     tryCatchLog (>= 1.1.0)
 Suggests:
     furrr (>= 0.1.0),
-    testthat (>= 2.1.0),
+    testthat (>= 3.0.0),
     fastmatch (>= 1.1.0),
     mlogit (>= 1.1.0),
     caret (>= 6.0.0),
@@ -118,3 +118,5 @@ Collate:
     'utils.R'
     'validate.R'
     'zzz.R'
+Config/testthat/parallel: true
+Config/testthat/edition: 3
diff --git a/NAMESPACE b/NAMESPACE
index 69b8daa9..0207e406 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -18,6 +18,7 @@ S3method(predict,ModelMultinomialLogit)
 S3method(simulate_choice,Model)
 S3method(simulate_choice,WrappedModel)
 S3method(simulate_choice,data.frame)
+S3method(simulate_choice,dymium.choice_table)
 S3method(simulate_choice,glm)
 S3method(simulate_choice,list)
 S3method(simulate_choice,train)
diff --git a/NEWS.md b/NEWS.md
index afacc55f..b6fec862 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -3,6 +3,8 @@
 ## New features
 
 - `ModelMultinomialLogit` and `ModelBinaryChoice` now have S3 `predict` and `summary` methods. Note that `ModelMultinomialLogit` requires `newdata` to be in the same format that is required by `mlogit`.
+- `Population$household_type()` now returns the number of members in household and remove individuals not belong to any household.
+- When calling `World$add()` and `name` is missing, it will see if the object has a `name` field, if it is a `Target` or a `Model`.
 
 ## Changes
 
@@ -10,6 +12,7 @@
 - add a `name` argument to `Model`'s constructor function and expose it as an R6 active field. 
 - `World$add()` can now be used to add a named `Model` without providing the `name` argument.
 - `World$add()` gained a `replace` argument with `TRUE` as its default value. 
+- `Generic` now has an active `name` field which will equal to `NULL` if no name is given.
 
 ## Bug fixes
 
diff --git a/R/Entity-functions.R b/R/Entity-functions.R
index 9ab56687..06abfc89 100644
--- a/R/Entity-functions.R
+++ b/R/Entity-functions.R
@@ -137,7 +137,7 @@ impute_history <- function(entity, ids, event = NULL) {
 #' add_history(Ind, ids = sample(Ind$get_ids(), 10), event = "event1", time = 1)
 #' combine_histories(world)
 combine_histories <- function(x) {
-  checkmate::expect_r6(x, classes = "Container")
+  checkmate::assert_r6(x, classes = "Container")
   get_history(x) %>%
     purrr::keep(., ~ !is.null(.x)) %>%
     purrr::map2(.x = ., .y = names(.),
diff --git a/R/Generic.R b/R/Generic.R
index b0aff8f2..e6fe478a 100644
--- a/R/Generic.R
+++ b/R/Generic.R
@@ -48,8 +48,11 @@ Generic <- R6Class(
   classname = "Generic",
   public = list(
 
-    initialize = function(...) {
-
+    initialize = function(name) {
+      if (!missing(name)) {
+        self$name <- name
+      }
+      invisible(self)
     },
 
     debug = function() {
@@ -126,6 +129,17 @@ Generic <- R6Class(
     }
   ),
 
+  active = list(
+    name = function(x) {
+      if (missing(x)) {
+        private$.name
+      } else {
+        checkmate::assert_string(x, null.ok = T, na.ok = FALSE)
+        private$.name <- x
+      }
+    }
+  ),
+
   private = list(
     .abstract = function(msg) {
       # this is a method for abstract methods
@@ -150,7 +164,9 @@ Generic <- R6Class(
       tag = character(),
       desc = character(),
       value = list()
-    )
+    ),
+
+    .name = NULL
 
   )
 )
diff --git a/R/Individual.R b/R/Individual.R
index 94b3f069..88599574 100644
--- a/R/Individual.R
+++ b/R/Individual.R
@@ -295,8 +295,7 @@ Individual <- R6::R6Class(
       result <-
         private$get_relationship(ids, type = "children") %>%
         dt_group_and_sort(x = ., groupby_col = pid_col, group_col = "child_id", sort_order = ids)
-      checkmate::expect_set_equal(ids, result[['sort_col']], ordered = T,
-                                  info = "`ids` and the result are not equal.")
+      checkmate::assert_set_equal(ids, result[['sort_col']], ordered = TRUE)
       result[["group_col"]]
     },
 
@@ -307,8 +306,7 @@ Individual <- R6::R6Class(
         .[, living_together := self$living_together(self_ids = get(pid_col), target_ids = child_id)] %>%
         .[living_together == TRUE] %>%
         dt_group_and_sort(x = ., groupby_col = pid_col, group_col = "child_id", sort_order = ids)
-      checkmate::expect_set_equal(ids, result[['sort_col']], ordered = T,
-                                  info = "`ids` and the result are not equal.")
+      checkmate::assert_set_equal(ids, result[['sort_col']], ordered = TRUE)
       result[["group_col"]]
     },
 
diff --git a/R/MatchingMarket.R b/R/MatchingMarket.R
index f100a774..ee12f713 100644
--- a/R/MatchingMarket.R
+++ b/R/MatchingMarket.R
@@ -99,8 +99,8 @@ MatchingMarket <- R6::R6Class(
                           grouping_vars = NULL,
                           max_market_size = 5000 ^ 2) {
       # CHECK INPUTS
-      checkmate::expect_data_table(agentset_A)
-      checkmate::expect_data_table(agentset_B)
+      checkmate::assert_data_table(agentset_A)
+      checkmate::assert_data_table(agentset_B)
 
       if (missing(id_col_A)) {
         stopifnot(uniqueN(agentset_A[, 1]) == nrow(agentset_A))
diff --git a/R/MatchingMarketOptimal.R b/R/MatchingMarketOptimal.R
index 5f65fe7d..3cb4ffa4 100644
--- a/R/MatchingMarketOptimal.R
+++ b/R/MatchingMarketOptimal.R
@@ -52,7 +52,7 @@ MatchingMarketOptimal <- R6::R6Class(
       parallel_wrapper <- function(...) {
         if (parallel) {
           stopifnot(requireNamespace('furrr'))
-          furrr::future_map_dfr(..., .options = furrr::future_options(globals = "self"))
+          furrr::future_map_dfr(..., .options = furrr::furrr_options(globals = "self"))
         } else {
           purrr::map_dfr(...)
         }
diff --git a/R/MatchingMarketStochastic.R b/R/MatchingMarketStochastic.R
index d11b53f2..8f1b44d0 100644
--- a/R/MatchingMarketStochastic.R
+++ b/R/MatchingMarketStochastic.R
@@ -64,7 +64,7 @@ MatchingMarketStochastic <- R6::R6Class(
       parallel_wrapper <- function(...) {
         if (parallel) {
           stopifnot(requireNamespace('furrr'))
-          furrr::future_map_dfr(..., .options = furrr::future_options(globals = "self"))
+          furrr::future_map_dfr(..., .options = furrr::furrr_options(globals = "self"))
         } else {
           purrr::map_dfr(...)
         }
diff --git a/R/Model.R b/R/Model.R
index a420f682..cfdc004b 100644
--- a/R/Model.R
+++ b/R/Model.R
@@ -100,8 +100,8 @@ Model <-
         checkmate::assert_function(preprocessing_fn, nargs = 1, null.ok = TRUE)
         self$preprocessing_fn <- preprocessing_fn
         self$set(x)
-        self$name <- name
-        invisible()
+        super$initialize(name = name)
+        invisible(self)
       },
       get = function() {
         private$.model
@@ -133,19 +133,10 @@ Model <-
           return(data.table::copy(private$.model))
         }
         get(".model", envir = private)
-      },
-      name = function(value) {
-        if (missing(value)) {
-          private$.name
-        } else {
-          checkmate::assert_string(value, null.ok = T, na.ok = FALSE)
-          private$.name <- value
-        }
       }
     ),
     private = list(
-      .model = NULL,
-      .name = NULL
+      .model = NULL
     )
   )
 
diff --git a/R/ModelMultinomialLogit.R b/R/ModelMultinomialLogit.R
index 1f4dc861..7736d395 100644
--- a/R/ModelMultinomialLogit.R
+++ b/R/ModelMultinomialLogit.R
@@ -65,7 +65,7 @@ ModelMultinomialLogit <- R6::R6Class(
     #'  choice_id (`integer()`), linear_comb (`numeric()`), prob (`numeric()`). Note
     #'  that, 'linear_comb' stands for linear combination (i.e. $$B1 * x1 + B2 * x2$$).
     predict = function(newdata, chooser_id_col, choice_id_col) {
-      checkmate::expect_data_frame(newdata)
+      checkmate::assert_data_frame(newdata)
       data.table(chooser_id = newdata[[chooser_id_col]],
                  choice_id = newdata[[choice_id_col]],
                  linear_comb = private$.compute_linear_combination(newdata, chooser_id_col, choice_id_col)) %>%
@@ -76,7 +76,7 @@ ModelMultinomialLogit <- R6::R6Class(
   private = list(
     .compute_linear_combination = function(newdata, chooser_id_col, choice_id_col) {
       if (inherits(newdata, "dfidx")) {
-        checkmate::expect_names(x = names(newdata$idx),
+        checkmate::assert_names(x = names(newdata$idx),
                                 identical.to = c(chooser_id_col, choice_id_col))
       } else {
         newdata <-
diff --git a/R/Population.R b/R/Population.R
index a19d4f32..03024c33 100644
--- a/R/Population.R
+++ b/R/Population.R
@@ -242,7 +242,9 @@ Population <- R6Class(
     leave_household = function(ind_ids) {
       # check that ids in ind_ids and their household ids exist
       stopifnot(self$get("Individual")$ids_exist(ids = ind_ids))
-      stopifnot(self$get("Household")$ids_exist(ids = self$get("Individual")$get_household_ids(ids = ind_ids)))
+      stopifnot(
+        self$get("Household")$ids_exist(
+          ids = self$get("Individual")$get_household_ids(ids = ind_ids)))
       # leave household
       self$get("Individual")$remove_household_id(ids = ind_ids)
       add_history(entity = self$get("Individual"),
@@ -286,6 +288,7 @@ Population <- R6Class(
         ), by = c(Ind$get_hid_col())] %>%
         # identify relationships
         .[, `:=`(
+          n_members = sapply(members, length),
           couple_hh = purrr::map2_lgl(members, partners, ~ {any(.y %in% .x)}),
           with_children = purrr::map2_lgl(members, parents, ~ {any(.y %in% .x)})
         )] %>%
@@ -304,7 +307,12 @@ Population <- R6Class(
           by.y = Ind$get_hid_col(),
           sort = FALSE,
           allow.cartesian = FALSE
-        )
+        ) %>%
+        # if there are individuals that don't belong to any household they would all
+        # be added into id:NA, so i thin
+        .[!is.na(id), ]
+
+
 
       checkmate::assert_character(household_type[["household_type"]], any.missing = FALSE)
 
diff --git a/R/Target.R b/R/Target.R
index a4381a75..af891846 100644
--- a/R/Target.R
+++ b/R/Target.R
@@ -13,12 +13,16 @@
 #' @section Construction:
 #'
 #' ```
-#' Target$new(x)
+#' Target$new(x, name)
 #' ```
 #'
 #' * `x` :: any object that passes `check_target()`\cr
 #' A target object or `NULL`.
 #'
+#' * `name` :: `character(1)`\cr
+#' Name/Alias of the Target object. This will be used as the [Target] name when
+#' it gets added to a [World].
+#'
 #' @section Active Field (read-only):
 #'
 #'  * `data`:: a target object\cr
@@ -61,7 +65,7 @@ Target <- R6::R6Class(
   classname = "Target",
   inherit = dymiumCore::Generic,
   public = list(
-    initialize = function(x) {
+    initialize = function(x, name) {
       assert_target(x, null.ok = TRUE)
       if (is.data.frame(x)) {
         if (!"time" %in% names(x)) {
@@ -80,6 +84,7 @@ Target <- R6::R6Class(
       } else {
         private$.data <- x
       }
+      super$initialize(name = name)
       invisible(self)
     },
 
diff --git a/R/World.R b/R/World.R
index 6e858f14..3b5d158f 100644
--- a/R/World.R
+++ b/R/World.R
@@ -137,10 +137,11 @@ World <- R6::R6Class(
       )
 
       if (checkmate::test_r6(x, "World")) {
-        stop("Adding a World object is not permitted.")
+        stop("Adding a World object to another World object is not permitted.")
       }
 
-      if ((inherits(x, "Entity") | inherits(x, "Container")) & !inherits(x, "Model") & !inherits(x, "Target")) {
+      if ((inherits(x, "Entity") | inherits(x, "Container")) &
+          !inherits(x, "Model") & !inherits(x, "Target")) {
         stopifnot(x$is_dymium_class())
         if (!missing(name)) {
           lg$warn("The given `name` will be ignored since the object in x \\
@@ -150,11 +151,12 @@ World <- R6::R6Class(
         name <- class(x)[[1]]
       }
 
-      if (inherits(x, "Model") && !is.null(x$name)) {
-        name = x$name
+      if (missing(name) && !is.null(x$name) &&
+          (inherits(x, "Model") | inherits(x, "Target"))) {
+        name <- x$name
       }
 
-      # only allows letters and underscores
+      # only allows letters and underscores\
       checkmate::assert_string(name,
                                pattern = "^[a-zA-Z_]*$",
                                na.ok = FALSE,
@@ -197,10 +199,14 @@ World <- R6::R6Class(
 
       if (name_object_exists) {
         if (replace) {
-          lg$warn("Replacing the object named `{name}` of class `{.class_old}` \\
+          warn_msg =
+            glue::glue(
+              "Replacing the object named `{name}` of class `{.class_old}` \\
                   with `{.class_new}`.",
-                  .class_old = self$get(x = name)$class()[[1]],
-                  .class_new = class(x)[[1]])
+              .class_old = self$get(x = name)$class()[[1]],
+              .class_new = class(x)[[1]]
+            )
+          warning(warn_msg)
           self$remove(name)
         } else {
           stop(glue::glue("{name} already exists in {.listname}. Only one instance \\
diff --git a/R/simulate_choice.R b/R/simulate_choice.R
index d7b293d6..e1ad9be6 100644
--- a/R/simulate_choice.R
+++ b/R/simulate_choice.R
@@ -22,7 +22,7 @@
 simulate_choice.train <- function(model, newdata, target = NULL, ...) {
   checkmate::assert_true(model$modelType == "Classification")
   probs <- predict(model, newdata, type = "prob")
-  simulate_choice(probs, target)
+  simulate_choice(create_choice_table(probs), target)
 }
 
 #' @rdname simulate_choice
@@ -56,7 +56,7 @@ simulate_choice.glm <- function(model, newdata, target = NULL, ...) {
     {data.table::data.table(x1 = .,
                            x2 = 1 - .)} %>%
     data.table::setnames(choices)
-  simulate_choice(probs, target)
+  simulate_choice(create_choice_table(probs), target)
 }
 
 #' @rdname simulate_choice
@@ -96,30 +96,91 @@ simulate_choice.WrappedModel <- function(model, newdata, target = NULL, ...) {
   } else {
     probs <- mlr::getPredictionProbabilities(pred)
   }
-  simulate_choice(probs, target)
+  simulate_choice(create_choice_table(probs), target)
 }
 
 #' @rdname simulate_choice
 #' @export
-simulate_choice.data.frame <- function(model, target = NULL, ...) {
-  probs <- model
-  checkmate::assert_data_frame(
+simulate_choice.data.frame <- function(model, newdata, target = NULL, ...) {
+
+  # convert to data.table
+  if (!is.data.table(model)) {
+    checkmate::assert_data_frame(model, min.rows = 1)
+    model <- as.data.table(model)
+  }
+
+  if (!is.data.table(newdata)) {
+    checkmate::assert_data_frame(newdata, min.rows = 1)
+    newdata <- as.data.table(newdata)
+  }
+
+  if (!xor("prob" %in% names(model), "probs" %in% names(model))) {
+    stop("`model` should contains a numeric probability column named `prob` in a binary",
+         " choice case or `probs` in a multiple choice case.")
+  }
+
+  match_vars <-
+    names(model)[!names(model) %in% c("prob", "probs", "choices")]
+
+  checkmate::assert_names(names(newdata), must.include = match_vars)
+
+  if ("prob" %in% names(model)) {
+    probs <-
+      merge(newdata, model, match_vars, sort = FALSE) %>%
+      .[, .(yes = prob, no = 1 - prob)]
+  }
+
+  if ("probs" %in% names(model)) {
+    if (!"choices" %in% names(model)) {
+      stop("`model` is missing a list column named `choices`.")
+    }
+    stop("`model` with multiple choices has not been developed yet :(.")
+  }
+
+  # check cases
+  checkmate::assert_data_table(
     probs,
     types = 'double',
     min.cols = 2,
+    nrows = nrow(newdata),
     any.missing = FALSE,
     null.ok = FALSE,
     col.names = 'unique'
   )
-  if (!is.data.table(probs)) {
-    setDT(probs)
+
+  simulate_choice(create_choice_table(probs), target)
+}
+
+#' @rdname simulate_choice
+#' @param choice_table a `choice_table` object, created by `create_choice_table()`.
+#' @export
+simulate_choice.dymium.choice_table <- function(choice_table, target = NULL, ...) {
+  checkmate::assert_data_frame(
+    choice_table,
+    types = 'double',
+    min.cols = 2,
+    any.missing = FALSE,
+    null.ok = FALSE,
+    col.names = 'unique'
+  )
+  if (!is.data.table(choice_table)) {
+    setDT(choice_table)
   }
-  choices <- names(probs)
+  choices <- names(choice_table)
   # random draw choices
   if (!is.null(target)) {
-    alignment(probs, target)
+    alignment(choice_table, target)
   } else {
-    purrr::pmap_chr(probs, ~ sample_choice(choices, 1, prob = (list(...))))
+    purrr::pmap_chr(choice_table, ~ sample_choice(choices, 1, prob = (list(...))))
   }
 }
 
+#' prepend dymium.choice_table
+#'
+#' @param x any object.
+#'
+#' @return `x`
+create_choice_table = function(x) {
+  class(x) <- c("dymium.choice_table", class(x))
+  x
+}
diff --git a/R/transition-fnc.R b/R/transition-fnc.R
index a76e2e56..aa8929cf 100644
--- a/R/transition-fnc.R
+++ b/R/transition-fnc.R
@@ -221,7 +221,6 @@ transition <-
 #' @export
 get_transition <- function(world, entity, model, target = NULL, targeted_ids = NULL, preprocessing_fn = NULL) {
 
-
   checkmate::assert_r6(world, classes = "World")
 
   if(!checkmate::test_string(entity, na.ok = FALSE)) {
@@ -254,6 +253,7 @@ get_transition <- function(world, entity, model, target = NULL, targeted_ids = N
       model$preprocessing_fn(e_data)
   }
   e_data <- dymiumCore::normalise_derived_vars(e_data)
+  # early return if no data
   if (nrow(e_data) == 0) {
     return(data.table(id = integer(), response = character()))
   }
diff --git a/R/utils.R b/R/utils.R
index 38c1c0c3..d7270c4c 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -348,7 +348,7 @@ dt_group_and_sort <- function(x, groupby_col, group_col, sort_order) {
   checkmate::assert_data_table(x)
   stopifnot(groupby_col %in% names(x))
   stopifnot(group_col %in% names(x))
-  checkmate::expect_integerish(sort_order, unique = T, lower = 0, min.len = 1)
+  checkmate::assert_integerish(sort_order, unique = TRUE, lower = 0, min.len = 1)
 
   # group and sort
   x_new <-
diff --git a/man/Target.Rd b/man/Target.Rd
index 512cdf7b..b419ff48 100644
--- a/man/Target.Rd
+++ b/man/Target.Rd
@@ -13,11 +13,14 @@ functions. If the target is dynamic then its \code{get} will return its target
 value at the current time or its closest time to the current time.
 }
 \section{Construction}{
-\preformatted{Target$new(x)
+\preformatted{Target$new(x, name)
 }
 \itemize{
 \item \code{x} :: any object that passes \code{check_target()}\cr
 A target object or \code{NULL}.
+\item \code{name} :: \code{character(1)}\cr
+Name/Alias of the Target object. This will be used as the \link{Target} name when
+it gets added to a \link{World}.
 }
 }
 
diff --git a/man/create_choice_table.Rd b/man/create_choice_table.Rd
new file mode 100644
index 00000000..b49b89b2
--- /dev/null
+++ b/man/create_choice_table.Rd
@@ -0,0 +1,17 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/simulate_choice.R
+\name{create_choice_table}
+\alias{create_choice_table}
+\title{prepend dymium.choice_table}
+\usage{
+create_choice_table(x)
+}
+\arguments{
+\item{x}{any object.}
+}
+\value{
+\code{x}
+}
+\description{
+prepend dymium.choice_table
+}
diff --git a/man/sample_choice_table.Rd b/man/sample_choice_table.Rd
new file mode 100644
index 00000000..d25a8b24
--- /dev/null
+++ b/man/sample_choice_table.Rd
@@ -0,0 +1,21 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/simulate_choice.R
+\name{sample_choice_table}
+\alias{sample_choice_table}
+\title{Sample a choice table}
+\usage{
+sample_choice_table(x, target = NULL, ...)
+}
+\arguments{
+\item{x}{a \code{choice_table} object.}
+
+\item{target}{a \link{Target} object.}
+
+\item{...dots}{}
+}
+\value{
+a character vector.
+}
+\description{
+Sample a choice table
+}
diff --git a/man/simulate_choice.Rd b/man/simulate_choice.Rd
index dbf2150d..864960e3 100644
--- a/man/simulate_choice.Rd
+++ b/man/simulate_choice.Rd
@@ -8,6 +8,7 @@
 \alias{simulate_choice.Model}
 \alias{simulate_choice.WrappedModel}
 \alias{simulate_choice.data.frame}
+\alias{simulate_choice.dymium.choice_table}
 \title{Simulate a choice situation}
 \usage{
 simulate_choice(model, ...)
@@ -22,7 +23,9 @@ simulate_choice(model, ...)
 
 \method{simulate_choice}{WrappedModel}(model, newdata, target = NULL, ...)
 
-\method{simulate_choice}{data.frame}(model, target = NULL, ...)
+\method{simulate_choice}{data.frame}(model, newdata, target = NULL, ...)
+
+\method{simulate_choice}{dymium.choice_table}(choice_table, target = NULL, ...)
 }
 \arguments{
 \item{model}{a \link{Model} object or an object in \code{\link[=SupportedTransitionModels]{SupportedTransitionModels()}}.}
@@ -33,6 +36,8 @@ simulate_choice(model, ...)
 
 \item{target}{a \link{Target} object or a named list this is for aligning the simulation
 outcome to an external target.}
+
+\item{choice_table}{a \code{choice_table} object, created by \code{create_choice_table()}.}
 }
 \value{
 a character vector
diff --git a/tests/testthat/test-Model.R b/tests/testthat/test-Model.R
index 81b944c5..728966ca 100644
--- a/tests/testthat/test-Model.R
+++ b/tests/testthat/test-Model.R
@@ -1,7 +1,6 @@
 test_that("Model initialisation", {
   m <- Model$new(list(x = 1), name = "model")
   expect_true(m$name == "model")
-
   m <- Model$new(list(x = 1))
   expect_null(m$null)
 })
diff --git a/tests/testthat/test-Population.R b/tests/testthat/test-Population.R
index f915d682..cdc0b388 100644
--- a/tests/testthat/test-Population.R
+++ b/tests/testthat/test-Population.R
@@ -180,3 +180,15 @@ test_that("`household_type` of two random hid vectors of the same set be equipva
     all(table(Pop$household_type(hid = sample(1:100))) == table(Pop$household_type(hid = sample(1:100))))
   )
 })
+
+# $leave_household -------------
+test_that("Population$leave_household()", {
+  create_toy_world()
+  Pop <- world$get("Population")
+  Ind <- world$get("Individual")
+  ind_ids <- sample(Ind$get_ids(), 10)
+  Pop$leave_household(ind_ids)
+  # Once individuals left households they cannot be leaving households again
+  expect_error(Pop$leave_household(ind_ids),
+               regexp = "Contains missing values")
+})
diff --git a/tests/testthat/test-World.R b/tests/testthat/test-World.R
index 2224bfe1..b15552b9 100644
--- a/tests/testthat/test-World.R
+++ b/tests/testthat/test-World.R
@@ -1,4 +1,7 @@
 test_that("add", {
+
+  lg$set_threshold("warn")
+
   w <- World$new()
 
   # add container
@@ -10,7 +13,7 @@ test_that("add", {
   # change to capture the warning messages
   lg$set_threshold("warn")
 
-  expect_output(w$add(
+  expect_warning(w$add(
     Population$new(
       ind_data = toy_individuals,
       hh_data = toy_households,
@@ -23,9 +26,9 @@ test_that("add", {
   w$add(Agent$new(toy_individuals, "pid"))
   w$add(Firm$new(toy_individuals, "pid"))
   expect_length(w$entities, 4)
-  expect_output(w$add(Individual$new(toy_individuals, "pid")),
+  expect_warning(w$add(Individual$new(toy_individuals, "pid")),
                  "Replacing")
-  expect_output(w$add(Household$new(toy_households, "hid")),
+  expect_warning(w$add(Household$new(toy_households, "hid")),
                  "Replacing")
 
   lg$set_threshold("fatal")
@@ -38,8 +41,11 @@ test_that("add", {
   w$add(Model$new(list(x = 1), "namedModel"))
   w$add(list(x = 1), "namedModel")
 
-  # add world ?
-  expect_error(w$add(w), regexp = "Adding a World object is not permitted.")
+  # a world within another world is not permitted
+  expect_error(
+    w$add(w),
+    regexp = "Adding a World object to another World object is not permitted."
+  )
 
 })
 
@@ -124,9 +130,22 @@ test_that("active fields", {
 })
 
 test_that("add target", {
-  t <- Target$new(x = list(yes = 10, no = 20))
   w <- World$new()
+
+  # name using the name arg
+  t <- Target$new(x = list(yes = 10, no = 20))
   w$add(x = t, name = "a_target")
+
+  expect_target(w$targets[["a_target"]], null.ok = FALSE)
+  expect_warning(w$add(x = t, name = "a_target"), regexp = "Replacing the object named")
+
+  # unnamed target
+  expect_error(w$add(x = t), regexp = "argument \"name\" is missing, with no default")
+
+  # named target
+  t <- Target$new(x = list(yes = 10, no = 20), name = "a_target")
+  expect_warning(w$add(x = t), regexp = "Replacing the object named")
+  expect_target(w$targets[["a_target"]], null.ok = FALSE)
   checkmate::expect_r6(w$targets$a_target, "Target")
 })
 
diff --git a/tests/testthat/test-makeModel.R b/tests/testthat/test-makeModel.R
index 6b3d8eb0..cad50ed2 100644
--- a/tests/testthat/test-makeModel.R
+++ b/tests/testthat/test-makeModel.R
@@ -7,6 +7,10 @@ test_that("makeModel", {
   checkmate::expect_numeric(predict(Mod, newdata = toy_individuals), finite = T, any.missing = FALSE)
   checkmate::expect_numeric(summary(Mod), names = "named")
 
+  # binary choice model without the dependent variable in newdata
+  # predict(Mod, newdata = toy_individuals[, -"sex"])
+  # predict(Mod)
+
   # mlogit model
   mlogit_model <- create_mlogit_model()
   Mod <- makeModel(mlogit_model)
diff --git a/tests/testthat/test-simulate-choice.R b/tests/testthat/test-simulate-choice.R
index 5a54babf..af9b5a87 100644
--- a/tests/testthat/test-simulate-choice.R
+++ b/tests/testthat/test-simulate-choice.R
@@ -27,11 +27,29 @@ test_that("simulate_choice.train multilabels works", {
 
 test_that("simulate_choice.data.frame works", {
   n_rows <- 10
+
+  # this used to work in commit:0602258ed2bdffb3827c0ac3870dbdd62b575d56, but now is defunct
   probs <- data.frame(yes = runif(n_rows), no = runif(n_rows), maybe = runif(n_rows))
-  checkmate::expect_character(simulate_choice(probs),
-                              pattern = "yes|no|maybe",
-                              any.missing = FALSE,
-                              len = n_rows)
+  expect_error(simulate_choice(probs))
+
+  model <- data.frame(age = c(0:99, 0:99),
+                      sex = c(rep('male', 100), rep('female', 100)),
+                      prob = 0.05)
+  checkmate::expect_character(
+    simulate_choice(model, newdata = toy_individuals),
+    pattern = "yes|no", len = nrow(toy_individuals)
+  )
+  checkmate::expect_character(
+    simulate_choice(as.data.table(model), newdata = toy_individuals),
+    pattern = "yes|no", len = nrow(toy_individuals)
+  )
+
+  model <- data.frame(age = 1,
+                      sex = "female",
+                      prob = 0.05)
+  expect_error(simulate_choice(model, newdata = toy_individuals),
+               regexp = "Assertion on 'probs' failed")
+
 })
 
 test_that("simulate_choice.WrappedModel from mlr works", {