diff --git a/R/args.R b/R/args.R
index c322629f6..254993403 100644
--- a/R/args.R
+++ b/R/args.R
@@ -681,7 +681,6 @@ DiagnoseArgs <- R6::R6Class(
 #' @param self A `CmdStanArgs` object.
 #' @return `TRUE` invisibly unless an error is thrown.
 validate_cmdstan_args <- function(self) {
-  validate_exe_file(self$exe_file)
   assert_dir_exists(self$output_dir, access = "rw")
 
   # at least 1 run id (chain id)
@@ -1073,22 +1072,12 @@ process_init.default <- function(init, ...) {
   return(init)
 }
 
-#' Remove the leftmost dimension if equal to 1
+#' Drop the draw dimension from `draws_of()` of a single draw
 #' @noRd
-#' @param x An array like object
+#' @param x The array `posterior::draws_of()` returns for one draw, whose
+#'   first dimension has length 1.
 .remove_leftmost_dim <- function(x) {
-  dims <- dim(x)
-  if (length(dims) == 1) {
-    return(drop(x))
-  } else if (dims[1] == 1) {
-    new_dims <- dims[-1]
-    # Create a call to subset the array, maintaining all remaining dimensions
-    subset_expr <- as.call(c(as.name("["), list(x), 1, rep(TRUE, length(new_dims)), drop = FALSE))
-    new_x <- eval(subset_expr)
-    return(array(new_x, dim = new_dims))
-  } else {
-    return(x)
-  }
+  array(x, dim = dim(x)[-1])
 }
 
 #' Write initial values to files if provided as posterior `draws` object
@@ -1344,21 +1333,19 @@ process_init_approx <- function(init, num_procs, model_variables = NULL,
 
   # resample_draws() needs num_procs distinct candidates
   if (num_procs > num_candidates) {
-    if (inherits(init, "CmdStanPathfinder")) {
-      algo_name <- " Pathfinder "
-      extra_msg <- " Try running Pathfinder with psis_resample=FALSE."
-    } else if (inherits(init, "CmdStanVB")) {
-      algo_name <- " VB "
-      extra_msg <- ""
-    } else if (inherits(init, "CmdStanLaplace")) {
-      algo_name <- " Laplace "
-      extra_msg <- ""
+    algo_name <- switch(
+      class(init)[1],
+      CmdStanPathfinder = "Pathfinder",
+      CmdStanVB = "VB",
+      CmdStanLaplace = "Laplace"
+    )
+    extra_msg <- if (inherits(init, "CmdStanPathfinder")) {
+      " Try running Pathfinder with psis_resample=FALSE."
     } else {
-      algo_name <- ""
-      extra_msg <- ""
+      ""
     }
-    stop(paste0("Not enough distinct draws (", num_procs, ") in", algo_name ,
-                "fit to create inits.", extra_msg))
+    stop(paste0("Not enough distinct draws (", num_procs, ") in ",
+                algo_name, " fit to create inits.", extra_msg))
   }
 
   # CmdStan PSIS-resamples Pathfinder draws only with multiple paths and lp weights
@@ -1493,20 +1480,6 @@ process_init.CmdStanMLE <- function(init, num_procs, model_variables = NULL,
 
 # Validation helpers ------------------------------------------------------
 
-#' Validate exe file exists
-#' @noRd
-#' @param exe_file Path to executable.
-#' @return Either throws an error or returns `invisible(TRUE)`
-validate_exe_file <- function(exe_file) {
-  if (!length(exe_file) ||
-      !nzchar(exe_file) ||
-      !file.exists(exe_file)) {
-    stop("There is no executable at '", exe_file, "'.", call. = FALSE)
-  }
-  invisible(TRUE)
-}
-
-
 #' Validate initial values
 #'
 #' For CmdStan `init` must be `NULL`, a single real number >= 0, or paths to
diff --git a/R/build_record.R b/R/build_record.R
index 15f5b6caa..847c535ac 100644
--- a/R/build_record.R
+++ b/R/build_record.R
@@ -127,7 +127,8 @@ assert_record_dependency_entry <- function(value, field) {
 
 #' Check a build record against the format version 1 schema
 #'
-#' Every check of a record's fields is here. `new_build_record()` runs it
+#' Every check of a record's fields except `format_version` is here,
+#' `read_build_record()` checks that first. `new_build_record()` runs it
 #' before a record is written and `read_build_record()` after one is read, so
 #' a record that passes when written passes when read. Fields the schema does
 #' not name are ignored. No feature in `reported_features` is required, since
@@ -141,14 +142,6 @@ assert_record_dependency_entry <- function(value, field) {
 validate_build_record <- function(record) {
   assert_record_shape(record, "object", "record")
 
-  format_version <- record[["format_version"]]
-  if (!checkmate::test_int(format_version, tol = 0) ||
-      format_version != build_record_format_version) {
-    stop_build_record_field(
-      "format_version", paste0("must be ", build_record_format_version)
-    )
-  }
-
   configuration <- assert_record_member(record, "configuration", "object")
   cpp_options <- assert_record_member(
     configuration, "cpp_options", "object", "configuration.cpp_options"
diff --git a/R/fit.R b/R/fit.R
index 00a44dac7..98603464b 100644
--- a/R/fit.R
+++ b/R/fit.R
@@ -41,11 +41,6 @@ CmdStanFit <- R6::R6Class(
       self$runset$num_procs()
     },
     print = function(variables = NULL, ..., digits = 2, max_rows = getOption("cmdstanr_max_rows", 10)) {
-      if (is.null(private$draws_) &&
-          !length(self$output_files(include_failed = FALSE))) {
-        stop("Fitting failed. Unable to print.", call. = FALSE)
-      }
-
       # filter variables before passing to summary to avoid computing anything
       # that won't be printed because of max_rows
       all_variables <- self$metadata()$variables
@@ -302,9 +297,6 @@ draws <- function(variables = NULL, inc_warmup = FALSE, format = getOption("cmds
   } else {
     format <- assert_valid_draws_format(format)
   }
-  if (!length(self$output_files(include_failed = FALSE))) {
-    stop("Fitting failed. Unable to retrieve the draws.", call. = FALSE)
-  }
   if (inc_warmup) {
     warning("`inc_warmup` is ignored except when used with CmdStanMCMC objects.",
             call. = FALSE)
@@ -609,9 +601,7 @@ unconstrain_draws <- function(files = NULL, draws = NULL,
                               format = getOption("cmdstanr_draws_format", "draws_array"),
                               inc_warmup = FALSE) {
   self$init_model_methods()
-  if (!(format %in% valid_draws_formats())) {
-    stop("Invalid draws format requested!", call. = FALSE)
-  }
+  format <- assert_valid_draws_format(format)
   if (!is.null(files) || !is.null(draws)) {
     if (!is.null(files) && !is.null(draws)) {
       stop("Either a list of CSV files or a draws object can be passed, not both",
@@ -1260,9 +1250,6 @@ CmdStanFit$set("public", name = "output", value = output)
 #'
 metadata <- function() {
   if (is.null(private$metadata_)) {
-    if (!length(self$output_files(include_failed = FALSE))) {
-      stop("Fitting failed. Unable to retrieve the metadata.", call. = FALSE)
-    }
     private$read_csv_()
   }
   private$metadata_
@@ -1538,7 +1525,8 @@ CmdStanMCMC <- R6::R6Class(
     inv_metric_ = NULL,
     read_csv_ = function(variables = NULL, sampler_diagnostics = NULL, format = getOption("cmdstanr_draws_format", "draws_array")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("No chains finished successfully. Unable to retrieve the draws.", call. = FALSE)
+        stop("No chains finished successfully. There is no output to read.",
+             call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(
         files = self$output_files(include_failed = FALSE),
@@ -1762,10 +1750,6 @@ sampler_diagnostics <- function(inc_warmup = FALSE, format = getOption("cmdstanr
   if (isTRUE(private$metadata_$algorithm == "fixed_param")) {
     stop("There are no sampler diagnostics when fixed_param = TRUE.", call. = FALSE)
   }
-  if (is.null(private$sampler_diagnostics_) &&
-      !length(self$output_files(include_failed = FALSE))) {
-    stop("No chains finished successfully. Unable to retrieve the sampler diagnostics.", call. = FALSE)
-  }
   to_read <- remaining_columns_to_read(
     requested = NULL,
     currently_read = posterior::variables(private$sampler_diagnostics_),
@@ -1928,9 +1912,6 @@ CmdStanMCMC$set("public", name = "diagnostic_summary", value = diagnostic_summar
 #' }
 #'
 inv_metric <- function(matrix = TRUE) {
-  if (!length(self$output_files(include_failed = FALSE))) {
-    stop("No chains finished successfully. Unable to retrieve the inverse metrics.", call. = FALSE)
-  }
   if (is.null(private$inv_metric_)) {
     private$read_csv_(variables = "", sampler_diagnostics = "")
   }
@@ -2058,7 +2039,7 @@ CmdStanMLE <- R6::R6Class(
     # inherits draws_ and metadata_ slots from CmdStanFit
     read_csv_ = function(format = getOption("cmdstanr_draws_format", "draws_matrix")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Optimization failed. Unable to retrieve the draws.", call. = FALSE)
+        stop("Optimization failed. There is no output to read.", call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(self$output_files(), format = format)
       private$draws_ <- csv_contents$point_estimates
@@ -2192,7 +2173,8 @@ CmdStanLaplace <- R6::R6Class(
     # inherits draws_ and metadata_ slots from CmdStanFit
     read_csv_ = function(format = getOption("cmdstanr_draws_format", "draws_matrix")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Laplace inference failed. Unable to retrieve the draws.", call. = FALSE)
+        stop("Laplace inference failed. There is no output to read.",
+             call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(self$output_files(), format = format)
       private$draws_ <- csv_contents$draws
@@ -2309,7 +2291,8 @@ CmdStanVB <- R6::R6Class(
     # inherits draws_ and metadata_ slots from CmdStanFit
     read_csv_ = function(format = getOption("cmdstanr_draws_format", "draws_matrix")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Variational inference failed. Unable to retrieve the draws.", call. = FALSE)
+        stop("Variational inference failed. There is no output to read.",
+             call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(self$output_files(), format = format)
       private$draws_ <- csv_contents$draws
@@ -2404,7 +2387,7 @@ CmdStanPathfinder <- R6::R6Class(
     # inherits draws_ and metadata_ slots from CmdStanFit
     read_csv_ = function(format = getOption("cmdstanr_draws_format", "draws_matrix")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Pathfinder failed. Unable to retrieve the draws.", call. = FALSE)
+        stop("Pathfinder failed. There is no output to read.", call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(self$output_files(), format = format)
       private$draws_ <- csv_contents$draws
@@ -2496,9 +2479,6 @@ CmdStanGQ <- R6::R6Class(
     },
     # override CmdStanFit draws method
     draws = function(variables = NULL, inc_warmup = FALSE, format = getOption("cmdstanr_draws_format", "draws_array")) {
-      if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Generating quantities for all MCMC chains failed. Unable to retrieve the generated quantities.", call. = FALSE)
-      }
       if (inc_warmup) {
         warning("`inc_warmup` is ignored except when used with CmdStanMCMC objects.",
                 call. = FALSE)
@@ -2538,7 +2518,8 @@ CmdStanGQ <- R6::R6Class(
     # inherits draws_ and metadata_ slots from CmdStanFit
     read_csv_ = function(variables = NULL, format = getOption("cmdstanr_draws_format", "draws_array")) {
       if (!length(self$output_files(include_failed = FALSE))) {
-        stop("Generating quantities for all MCMC chains failed. Unable to retrieve the generated quantities.", call. = FALSE)
+        stop("Generating quantities for all MCMC chains failed. ",
+             "There is no output to read.", call. = FALSE)
       }
       csv_contents <- read_cmdstan_csv(
         files = self$output_files(include_failed = FALSE),
diff --git a/R/run.R b/R/run.R
index a6b42c2ed..069cff1e8 100644
--- a/R/run.R
+++ b/R/run.R
@@ -807,9 +807,6 @@ CmdStanProcs <- R6::R6Class(
     show_stdout_messages = function () {
       private$show_stdout_messages_
     },
-    show_stderr_messages = function () {
-      private$show_stderr_messages_
-    },
     num_procs = function() {
       private$num_procs_
     },
diff --git a/R/utils.R b/R/utils.R
index 0add1353f..f27f591c9 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -406,8 +406,6 @@ as_draws_format_fun <- function(draws_format) {
     f <- posterior::as_draws_matrix
   } else if (draws_format %in% c("draws_list", "list")) {
     f <- posterior::as_draws_list
-  } else if (draws_format %in% c("draws_rvars", "rvars")) {
-    f <- posterior::as_draws_rvars
   }
   f
 }
@@ -448,9 +446,7 @@ maybe_convert_draws_format <- function(draws, format, ...) {
     "df" = posterior::as_draws_df(draws, ...),
     "data.frame" = posterior::as_draws_df(draws, ...),
     "list" = posterior::as_draws_list(draws, ...),
-    "matrix" = posterior::as_draws_matrix(draws, ...),
-    "rvars" = posterior::as_draws_rvars(draws, ...),
-    stop("Invalid draws format.", call. = FALSE)
+    "matrix" = posterior::as_draws_matrix(draws, ...)
   )
 }
 
@@ -462,9 +458,7 @@ create_draws_format <- function(format, ...) {
     "df" = posterior::draws_df(...),
     "data.frame" = posterior::draws_df(...),
     "list" = posterior::draws_list(...),
-    "matrix" = posterior::draws_matrix(...),
-    "rvars" = posterior::draws_rvars(...),
-    stop("Invalid draws format.", call. = FALSE)
+    "matrix" = posterior::draws_matrix(...)
   )
 }
 
diff --git a/tests/testthat/test-build-record.R b/tests/testthat/test-build-record.R
index 67667c156..92b3c35aa 100644
--- a/tests/testthat/test-build-record.R
+++ b/tests/testthat/test-build-record.R
@@ -233,6 +233,12 @@ test_that("the validator names the field that fails", {
     rebuild(repeated_option), "`configuration.cpp_options`", fixed = TRUE
   )
 
+  odd_name <- base
+  odd_name$configuration$cpp_options <- list(`1THREADS` = "true")
+  expect_error(
+    rebuild(odd_name), "`configuration.cpp_options.1THREADS`", fixed = TRUE
+  )
+
   unknown_kind <- base
   unknown_kind$untracked_dependencies <- list(
     list(kind = "mystery", detected_in = "make/local")
diff --git a/tests/testthat/test-csv.R b/tests/testthat/test-csv.R
index 1a49bf4d0..f2a254645 100644
--- a/tests/testthat/test-csv.R
+++ b/tests/testthat/test-csv.R
@@ -976,6 +976,8 @@ test_that("as_cmdstan_fit creates fitted model objects from csv", {
     error = TRUE,
     fits$laplace$mode()
   )
+
+  expect_length(fits$mcmc$inv_metric(), fit_logistic_thin_1$num_chains())
 })
 
 test_that("as_cmdstan_fit can check MCMC diagnostics", {
diff --git a/tests/testthat/test-data.R b/tests/testthat/test-data.R
index 6daacdff1..bae6fa052 100644
--- a/tests/testthat/test-data.R
+++ b/tests/testthat/test-data.R
@@ -223,7 +223,9 @@ test_that("process_fitted_params() works with draws_array", {
 
 test_that("process_fitted_params() works with draws_array without lp__", {
   fit <- testing_fit("logistic", method = "sample", seed = 123)
-  fit_params_files <- process_fitted_params(posterior::subset_draws(fit$draws(), variables = c("alpha", "beta[1]", "beta[2]", "beta[3]")))
+  fit_params_files <- process_fitted_params(posterior::subset_draws(
+    fit$draws(), variable = c("alpha", "beta[1]", "beta[2]", "beta[3]")
+  ))
   expect_true(all(file.exists(fit_params_files)))
   chain <- 1
   for(file in fit_params_files) {
diff --git a/tests/testthat/test-failed-chains.R b/tests/testthat/test-failed-chains.R
index 08b8ef0fc..cd31e7ce3 100644
--- a/tests/testthat/test-failed-chains.R
+++ b/tests/testthat/test-failed-chains.R
@@ -121,15 +121,23 @@ test_that("$save_* methods save all files regardless of chain failure", {
 })
 
 test_that("errors when using draws after all chains fail", {
-  expect_error(fit_all_fail$summary(), "No chains finished successfully")
-  expect_error(fit_all_fail$draws(), "No chains finished successfully")
-  expect_error(fit_all_fail$sampler_diagnostics(), "No chains finished successfully")
+  no_output <- "No chains finished successfully"
+  expect_error(fit_all_fail$summary(), no_output)
+  expect_error(fit_all_fail$draws(), no_output)
+  expect_error(fit_all_fail$sampler_diagnostics(), no_output)
   expect_error(fit_all_fail$cmdstan_summary(), "Unable to run bin/stansummary")
   expect_error(fit_all_fail$cmdstan_diagnose(), "Unable to run bin/diagnose")
-  expect_error(fit_all_fail$print(), "Fitting failed. Unable to print")
-  expect_error(fit_all_fail$inv_metric(), "No chains finished successfully")
-  expect_error(fit_all_fail$metadata(), "Fitting failed. Unable to retrieve the metadata")
-  expect_error(fit_all_fail$inv_metric(), "No chains finished successfully")
+  expect_error(fit_all_fail$print(), no_output)
+  expect_error(fit_all_fail$inv_metric(), no_output)
+  expect_error(fit_all_fail$metadata(), no_output)
+})
+
+test_that("a fit whose chains all failed cannot be used as init", {
+  expect_error(
+    mod$sample(data = list(pr_fail = 0), chains = 1, refresh = 0,
+               init = fit_all_fail),
+    "unable to create initial values from a model with no samples"
+  )
 })
 
 test_that("can use draws after some chains fail", {
@@ -166,12 +174,12 @@ test_that("errors when using draws after variational fais", {
     ),
     "Fitting finished unexpectedly!"
   )
-  expect_error(fit$print(), "Fitting failed. Unable to print.")
-  expect_error(fit$summary(), "Fitting failed. Unable to retrieve the draws.")
-  expect_error(fit$draws(), "Fitting failed. Unable to retrieve the draws.")
+  expect_error(fit$print(), "Variational inference failed")
+  expect_error(fit$summary(), "Variational inference failed")
+  expect_error(fit$draws(), "Variational inference failed")
   expect_error(fit$cmdstan_summary(), "Unable to run bin/stansummary")
   expect_error(fit$cmdstan_diagnose(), "Unable to run bin/diagnose")
-  expect_error(fit$metadata(), "Fitting failed. Unable to retrieve the metadata.")
+  expect_error(fit$metadata(), "Variational inference failed")
 })
 
 test_that("gq chains error on wrong input CSV", {
@@ -197,15 +205,15 @@ test_that("gq chains error on wrong input CSV", {
 
   expect_error(
     fit$draws(),
-    "Generating quantities for all MCMC chains failed. Unable to retrieve the generated quantities."
+    "Generating quantities for all MCMC chains failed"
   )
   expect_error(
     fit$metadata(),
-    "Fitting failed. Unable to retrieve the metadata."
+    "Generating quantities for all MCMC chains failed"
   )
   expect_error(
     fit$print(),
-    "Fitting failed. Unable to print."
+    "Generating quantities for all MCMC chains failed"
   )
   expect_warning(
     utils::capture.output(
diff --git a/tests/testthat/test-fit-init.R b/tests/testthat/test-fit-init.R
index 57f915a3d..45879d1a8 100644
--- a/tests/testthat/test-fit-init.R
+++ b/tests/testthat/test-fit-init.R
@@ -282,4 +282,25 @@ test_that("Draws Object with NA or Inf throws error", {
   draws_df[1, 4] = NA
   expect_error(mod_logistic$sample(
     data = data_list_logistic, seed = 1234, refresh=0, init = draws_df[1:4, ]), "alpha, beta contains NA or Inf values!")
+
+  mod_bern <- testing_model("bernoulli")
+  fit_bern <- testing_fit("bernoulli", method = "laplace", refresh = 0)
+  draws_bern <- fit_bern$draws()
+  draws_bern[1, "theta"] <- NA
+  expect_error(
+    mod_bern$sample(data = testing_data("bernoulli"), chains = 1,
+                    refresh = 0, init = draws_bern[1, ]),
+    "Variable: theta contains NA or Inf values!"
+  )
+})
+
+test_that("a fit used as init must share parameters with the model", {
+  fit_logistic <- testing_fit("logistic", method = "sample", refresh = 0)
+  expect_error(
+    testing_model("bernoulli")$sample(
+      data = testing_data("bernoulli"), chains = 1, refresh = 0,
+      init = fit_logistic
+    ),
+    "None of the names of the parameters"
+  )
 })
diff --git a/tests/testthat/test-fit-mcmc.R b/tests/testthat/test-fit-mcmc.R
index b78009bfc..e868f6a55 100644
--- a/tests/testthat/test-fit-mcmc.R
+++ b/tests/testthat/test-fit-mcmc.R
@@ -299,6 +299,7 @@ test_that("loo method works if log_lik is available", {
   fit_bernoulli <- testing_fit("bernoulli_log_lik")
   expect_s3_class(suppressWarnings(fit_bernoulli$loo(cores = 1, save_psis = TRUE)), "loo")
   expect_s3_class(suppressWarnings(fit_bernoulli$loo(r_eff = FALSE)), "loo")
+  expect_s3_class(suppressWarnings(fit_bernoulli$loo(r_eff = TRUE)), "loo")
 
   expect_error(
     fit_bernoulli$loo(variables = c("log_lik", "beta")),
@@ -379,6 +380,7 @@ test_that("draws() works for different formats", {
   expect_true(posterior::is_draws_array(a))
   a <- fit_mcmc$draws(format = "df")
   expect_true(posterior::is_draws_df(a))
+  expect_true(posterior::is_draws_df(fit_mcmc$draws(format = "data.frame")))
 })
 
 test_that("draws() errors if invalid format", {
@@ -386,6 +388,10 @@ test_that("draws() errors if invalid format", {
     fit_mcmc$draws(format = "bad_format"),
     "The supplied draws format is not valid"
   )
+  expect_error(
+    fit_mcmc$draws(format = "rvars"),
+    "convert after extracting the draws"
+  )
 })
 
 test_that("diagnostic_summary() works", {
@@ -421,6 +427,9 @@ test_that("diagnostic_summary() works", {
   )
   expect_equal(diagnostics$ebfmi, NA)
 
+  expect_no_message(quiet <- fit$diagnostic_summary(quiet = TRUE))
+  expect_equal(quiet, diagnostics)
+
   expect_equal(fit$diagnostic_summary(""), list())
   expect_equal(fit$diagnostic_summary(NULL), list())
 })
diff --git a/tests/testthat/test-fit-mle.R b/tests/testthat/test-fit-mle.R
index 40ee475df..04806010a 100644
--- a/tests/testthat/test-fit-mle.R
+++ b/tests/testthat/test-fit-mle.R
@@ -76,7 +76,7 @@ test_that("no error when checking estimates after failure", {
     fit <- cmdstanr_example("schools", method = "optimize", seed = 123), # optim ålways fails for this
     "Fitting finished unexpectedly"
   )
-  expect_error(fit$summary(), "Fitting failed. Unable to retrieve the draws.")
+  expect_error(fit$summary(), "Optimization failed")
 })
 
 test_that("draws() works for different formats", {
diff --git a/tests/testthat/test-fit-shared.R b/tests/testthat/test-fit-shared.R
index 304cf87a7..90ead56f5 100644
--- a/tests/testthat/test-fit-shared.R
+++ b/tests/testthat/test-fit-shared.R
@@ -8,9 +8,15 @@ fits[["variational"]] <- testing_fit("logistic", method = "variational",
                                      seed = 123, save_latent_dynamics = TRUE)
 fits[["optimize"]] <- testing_fit("logistic", method = "optimize", seed = 123)
 fits[["laplace"]] <- testing_fit("logistic", method = "laplace", seed = 123)
+fits[["pathfinder"]] <- testing_fit("logistic", method = "pathfinder",
+                                    seed = 123)
 fit_bern <- testing_fit("bernoulli", method = "sample", seed = 123)
-fits[["generate_quantities"]] <- testing_fit("bernoulli_ppc", method = "generate_quantities", fitted_params = fit_bern, seed = 123)
-all_methods <- c("sample", "optimize", "laplace", "variational", "generate_quantities")
+fits[["generate_quantities"]] <- testing_fit(
+  "bernoulli_ppc", method = "generate_quantities", fitted_params = fit_bern,
+  seed = 123
+)
+all_methods <- c("sample", "optimize", "laplace", "variational", "pathfinder",
+                 "generate_quantities")
 
 
 test_that("*_files() methods return the right number of paths", {
@@ -216,6 +222,16 @@ test_that("save_object() method works with qs2 format", {
   expect_identical(fit2$return_codes(), fit$return_codes())
 })
 
+test_that("save_object() says when qs2 is not installed", {
+  local_mocked_bindings(
+    requireNamespace = function(...) FALSE, .package = "base"
+  )
+  expect_error(
+    fits[["sample"]]$save_object(tempfile(fileext = ".qs2"), format = "qs2"),
+    "qs2 package is required"
+  )
+})
+
 test_that("save_object() method works with profiles", {
   mod <- testing_model("logistic_profiling")
   utils::capture.output(
diff --git a/tests/testthat/test-install.R b/tests/testthat/test-install.R
index 7c597f47b..51520d8c1 100644
--- a/tests/testthat/test-install.R
+++ b/tests/testthat/test-install.R
@@ -242,15 +242,19 @@ test_that("Install from release file works", {
     "https://github.com/stan-dev/cmdstan/releases/download/v2.37.0/cmdstan-2.37.0.tar.gz",
     destfile)
 
-  expect_message(
-    expect_output(
-      install_cmdstan(dir = dir, cores = CORES, quiet = FALSE, overwrite = TRUE,
-                      release_file = destfile,
-                      wsl = os_is_wsl()),
-      "Compiling C++ code",
+  expect_warning(
+    expect_message(
+      expect_output(
+        install_cmdstan(dir = dir, cores = CORES, quiet = FALSE,
+                        overwrite = TRUE, release_file = destfile,
+                        version = "2.37.0", wsl = os_is_wsl()),
+        "Compiling C++ code",
+        fixed = TRUE
+      ),
+      "CmdStan path set",
       fixed = TRUE
     ),
-    "CmdStan path set",
+    "release_file and release_url/version shouldn't both be specified",
     fixed = TRUE
   )
 })
diff --git a/tests/testthat/test-knitr.R b/tests/testthat/test-knitr.R
index 06a0b8686..588f19c23 100644
--- a/tests/testthat/test-knitr.R
+++ b/tests/testthat/test-knitr.R
@@ -24,6 +24,15 @@ test_that("eng_cmdstan works", {
   expect_interactive_message(eng_cmdstan(opts), "Compiling Stan program")
   opts$eval <- FALSE
   expect_noninteractive_silent(eng_cmdstan(opts))
+
+  opts$eval <- TRUE
+  opts$cache <- FALSE
+  expect_interactive_message(eng_cmdstan(opts), "Compiling Stan program")
+  opts$cache <- TRUE
+  opts$cache.path <- NA
+  opts$label <- "cmdstanr-knitr"
+  withr::local_dir(withr::local_tempdir())
+  expect_interactive_message(eng_cmdstan(opts), "Compiling Stan program")
 })
 
 test_that("register_knitr_engine works with and without override", {
diff --git a/tests/testthat/test-model-code-print.R b/tests/testthat/test-model-code-print.R
index d9740d944..d5565f40f 100644
--- a/tests/testthat/test-model-code-print.R
+++ b/tests/testthat/test-model-code-print.R
@@ -84,3 +84,11 @@ test_that("check_syntax() errors if only exe and no Stan file", {
     fixed = TRUE
   )
 })
+
+test_that("print(line_numbers = TRUE) numbers the lines", {
+  lines <- mod$code()
+  expect_equal(
+    capture.output(mod$print(line_numbers = TRUE)),
+    paste(base::format(seq_along(lines)), lines, sep = ": ")
+  )
+})
diff --git a/tests/testthat/test-model-methods.R b/tests/testthat/test-model-methods.R
index 08a8c8164..167dffb63 100644
--- a/tests/testthat/test-model-methods.R
+++ b/tests/testthat/test-model-methods.R
@@ -297,6 +297,20 @@ test_that("unconstrain_draws returns correct values", {
   expect_message(fit$unconstrain_draws(draws = fit$draws(), inc_warmup = TRUE),
                  "`inc_warmup` cannot be used with a draws object. Ignoring.")
 
+  expect_error(
+    fit$unconstrain_draws(files = fit$output_files(), draws = fit$draws()),
+    "not both"
+  )
+  expect_true(posterior::is_draws_df(fit$unconstrain_draws(format = "df")))
+  expect_true(
+    posterior::is_draws_df(fit$unconstrain_draws(format = "data.frame"))
+  )
+  expect_true(posterior::is_draws_list(fit$unconstrain_draws(format = "list")))
+  expect_error(
+    fit$unconstrain_draws(format = "rvars"),
+    "convert after extracting the draws"
+  )
+
   # With a lower-bounded constraint, the parameter draws should be the
   # exponentiation of the unconstrained draws
   model_code <- "
diff --git a/tests/testthat/test-path.R b/tests/testthat/test-path.R
index c71c240b0..a8dbfce7a 100644
--- a/tests/testthat/test-path.R
+++ b/tests/testthat/test-path.R
@@ -226,6 +226,25 @@ test_that("cmdstan_default_path() orders install directories by CmdStan version"
   )
 })
 
+test_that("cmdstan_default_path() prefers a release over its rc", {
+  installs <- withr::local_tempdir(pattern = "cmdstan-rc-installs")
+  dir.create(file.path(installs, "cmdstan-2.36.0-rc1"))
+  expect_equal(
+    cmdstan_default_path(dir = installs),
+    file.path(installs, "cmdstan-2.36.0-rc1")
+  )
+  dir.create(file.path(installs, "cmdstan-2.36.0"))
+  expect_equal(
+    cmdstan_default_path(dir = installs), file.path(installs, "cmdstan-2.36.0")
+  )
+})
+
+test_that("set_cmdstan_path() errors when the makefile has no version line", {
+  path <- withr::local_tempdir(pattern = "cmdstan-no-version")
+  writeLines("STAN ?= stan/", file.path(path, "makefile"))
+  expect_error(set_cmdstan_path(path), "missing a version number")
+})
+
 test_that("cmdstan_default_path() returns NULL for empty custom install directories", {
   installs <- withr::local_tempdir(pattern = "cmdstan-empty-installs")
 
diff --git a/tests/testthat/test-stan-file-functions.R b/tests/testthat/test-stan-file-functions.R
index 4384ea88c..4fc3594ec 100644
--- a/tests/testthat/test-stan-file-functions.R
+++ b/tests/testthat/test-stan-file-functions.R
@@ -60,6 +60,22 @@ test_that("format_stan_file() formats a program", {
     format_stan_file(include_model$stan_file, canonicalize = list("includes")),
     "real divide_real_by_two", fixed = TRUE
   )
+
+  expect_output(
+    format_stan_file(stan_file, canonicalize = TRUE), "  real y;", fixed = TRUE
+  )
+  long_line <- withr::local_tempfile(
+    lines = paste0(
+      "parameters {real y;} model {y ~ normal(0, ",
+      paste(rep("1", 20), collapse = " + "), ");}"
+    ),
+    fileext = ".stan"
+  )
+  expect_gt(max(nchar(capture.output(format_stan_file(long_line)))), 30)
+  format_stan_file(
+    long_line, max_line_length = 30, overwrite_file = TRUE, backup = FALSE
+  )
+  expect_true(all(nchar(readLines(long_line)) <= 30))
 })
 
 test_that("variables_stan_file() reports a program's variables", {