diff --git a/R/edition.R b/R/edition.R
index aef968bd0..7712877f6 100644
--- a/R/edition.R
+++ b/R/edition.R
@@ -27,8 +27,8 @@ edition_deprecate <- function(in_edition, what, instead = NULL) {
     return()
   }
 
-  warn(c(
-    paste0("`", what, "` was deprecated in ", edition_name(in_edition), "."),
+  cli::cli_warn(c(
+    "{.code {what}} was deprecated in {edition_name(in_edition)}.",
     i = instead
   ))
 }
@@ -40,7 +40,7 @@ edition_require <- function(in_edition, what) {
     return()
   }
 
-  stop(paste0("`", what, "` requires ", edition_name(in_edition), "."))
+  cli::cli_abort("{.code {what}} requires {edition_name(in_edition)}.")
 }
 
 edition_name <- function(x) {
diff --git a/R/expect-comparison.R b/R/expect-comparison.R
index d83e07879..46c6f9a41 100644
--- a/R/expect-comparison.R
+++ b/R/expect-comparison.R
@@ -39,8 +39,8 @@ expect_compare_ <- function(
 
   cmp <- op(act$val, exp$val)
   if (length(cmp) != 1 || !is.logical(cmp)) {
-    abort(
-      "Result of comparison must be a single logical value",
+    cli::cli_abort(
+      "Result of comparison must be a single logical value.",
       call = trace_env
     )
   }
@@ -112,14 +112,14 @@ expect_gte <- function(object, expected, label = NULL, expected.label = NULL) {
 #' @param ... All arguments passed on to `expect_lt()`/`expect_gt()`.
 #' @keywords internal
 expect_less_than <- function(...) {
-  warning("Deprecated: please use `expect_lt()` instead", call. = FALSE)
+  cli::cli_warn("Deprecated: please use {.fn expect_lt} instead.")
   expect_lt(...)
 }
 
 #' @rdname expect_less_than
 #' @export
 expect_more_than <- function(...) {
-  warning("Deprecated: please use `expect_gt()` instead", call. = FALSE)
+  cli::cli_warn("Deprecated: please use {.fn expect_gt} instead.")
   expect_gt(...)
 }
 
diff --git a/R/expect-condition.R b/R/expect-condition.R
index 6d698d4ca..449692c32 100644
--- a/R/expect-condition.R
+++ b/R/expect-condition.R
@@ -169,7 +169,7 @@ expect_warning <- function(
 
   if (edition_get() >= 3) {
     if (!missing(all)) {
-      warn("The `all` argument is deprecated")
+      cli::cli_warn("The {.arg all} argument is deprecated.")
     }
 
     expect_condition_matching_(
diff --git a/R/expect-known.R b/R/expect-known.R
index 91523a801..db4ea366f 100644
--- a/R/expect-known.R
+++ b/R/expect-known.R
@@ -79,7 +79,7 @@ expect_known_output <- function(
 
 compare_file <- function(path, lines, ..., update = TRUE, info = NULL) {
   if (!file.exists(path)) {
-    warning("Creating reference output", call. = FALSE)
+    cli::cli_warn("Creating reference output.")
     brio::write_lines(lines, path)
     return(pass(NULL))
   }
@@ -88,11 +88,11 @@ compare_file <- function(path, lines, ..., update = TRUE, info = NULL) {
   if (update) {
     brio::write_lines(lines, path)
     if (!all_utf8(lines)) {
-      warning("New reference output is not UTF-8 encoded", call. = FALSE)
+      cli::cli_warn("New reference output is not UTF-8 encoded.")
     }
   }
   if (!all_utf8(old_lines)) {
-    warning("Reference output is not UTF-8 encoded", call. = FALSE)
+    cli::cli_warn("Reference output is not UTF-8 encoded.")
   }
 
   comp <- waldo_compare(
@@ -178,7 +178,7 @@ expect_known_value <- function(
   act <- quasi_label(enquo(object), label)
 
   if (!file.exists(file)) {
-    warning("Creating reference value", call. = FALSE)
+    cli::cli_warn("Creating reference value.")
     saveRDS(object, file, version = version)
   } else {
     ref_val <- readRDS(file)
@@ -232,7 +232,7 @@ expect_known_hash <- function(object, hash = NULL) {
   }
 
   if (is.null(hash)) {
-    warning(paste0("No recorded hash: use ", substr(act_hash, 1, 10)))
+    cli::cli_warn("No recorded hash: use {substr(act_hash, 1, 10)}.")
   } else {
     if (hash != act_hash) {
       msg <- sprintf("Value hashes to %s, not %s", act_hash, hash)
diff --git a/R/expect-setequal.R b/R/expect-setequal.R
index 095b43419..34e1ea904 100644
--- a/R/expect-setequal.R
+++ b/R/expect-setequal.R
@@ -131,35 +131,6 @@ expect_in <- function(object, expected) {
 
 # Helpers ----------------------------------------------------------------------
 
-check_map_names <- function(
-  x,
-  error_arg = caller_arg(x),
-  error_call = caller_env()
-) {
-  nms <- names2(x)
-
-  if (anyDuplicated(nms)) {
-    dups <- unique(nms[duplicated(nms)])
-    cli::cli_abort(
-      c(
-        "All elements in {.arg {error_arg}} must have unique names.",
-        x = "Duplicate names: {.str {dups}}"
-      ),
-      call = error_call
-    )
-  }
-  if (any(nms == "")) {
-    empty <- which(nms == "")
-    cli::cli_abort(
-      c(
-        "All elements in {.arg {error_arg}} must have names.",
-        x = "Empty names at position{?s}: {empty}"
-      ),
-      call = error_call
-    )
-  }
-}
-
 check_vector <- function(
   x,
   error_arg = caller_arg(x),
diff --git a/R/expectation.R b/R/expectation.R
index a95fa176f..05322fda5 100644
--- a/R/expectation.R
+++ b/R/expectation.R
@@ -189,11 +189,9 @@ as.expectation.skip <- function(x, ..., srcref = NULL) {
 
 #' @export
 as.expectation.default <- function(x, srcref = NULL) {
-  stop(
-    "Don't know how to convert '",
-    paste(class(x), collapse = "', '"),
-    "' to expectation.",
-    call. = FALSE
+  cli::cli_abort(
+    "Don't know how to convert {.cls {class(x)}} to expectation.",
+    call = NULL
   )
 }
 
diff --git a/R/mock.R b/R/mock.R
index 139671620..4a0cdf8dc 100644
--- a/R/mock.R
+++ b/R/mock.R
@@ -27,9 +27,11 @@ with_mock <- function(..., .env = topenv()) {
   mock_qual_names <- names(dots)
 
   if (all(mock_qual_names == "")) {
-    warning(
-      "Not mocking anything. Please use named parameters to specify the functions you want to mock.",
-      call. = FALSE
+    cli::cli_warn(
+      c(
+        "Not mocking anything.",
+        "i" = "Please use named parameters to specify the functions you want to mock."
+      )
     )
     code_pos <- rep(TRUE, length(dots))
   } else {
@@ -85,11 +87,8 @@ extract_mocks <- function(funs, .env) {
       pkg_name <- gsub(pkg_and_name_rx, "\\1", qual_name)
 
       if (is_base_pkg(pkg_name)) {
-        stop(
-          "Can't mock functions in base packages (",
-          pkg_name,
-          ")",
-          call. = FALSE
+        cli::cli_abort(
+          "Can't mock functions in base package {.pkg {pkg_name}}."
         )
       }
 
@@ -102,13 +101,8 @@ extract_mocks <- function(funs, .env) {
       env <- asNamespace(pkg_name)
 
       if (!exists(name, envir = env, mode = "function")) {
-        stop(
-          "Function ",
-          name,
-          " not found in environment ",
-          environmentName(env),
-          ".",
-          call. = FALSE
+        cli::cli_abort(
+          "Function {.fn {name}} not found in environment {environmentName(env)}."
         )
       }
       mock(name = name, env = env, new = funs[[qual_name]])
diff --git a/R/mock2.R b/R/mock2.R
index 1939b6fe5..bf61f55de 100644
--- a/R/mock2.R
+++ b/R/mock2.R
@@ -185,18 +185,18 @@ local_bindings_rebind <- function(..., .env = .frame, .frame = caller_env()) {
   invisible()
 }
 
-dev_package <- function() {
+dev_package <- function(call = caller_env()) {
   if (is_testing() && testing_package() != "") {
     testing_package()
   } else {
     loaded <- loadedNamespaces()
     is_dev <- map_lgl(loaded, function(x) !is.null(pkgload::dev_meta(x)))
     if (sum(is_dev) == 0) {
-      cli::cli_abort("No packages loaded with pkgload")
+      cli::cli_abort("No packages loaded with pkgload", call = call)
     } else if (sum(is_dev) == 1) {
       loaded[is_dev]
     } else {
-      cli::cli_abort("Multiple packages loaded with pkgload")
+      cli::cli_abort("Multiple packages loaded with pkgload", call = call)
     }
   }
 }
diff --git a/R/old-school.R b/R/old-school.R
index df2683193..b3fcb397d 100644
--- a/R/old-school.R
+++ b/R/old-school.R
@@ -139,9 +139,8 @@ throws_error <- function(regexp = NULL, ...) {
 #' @export
 #' @param amount maximum duration in seconds
 takes_less_than <- function(amount) {
-  warning(
-    "takes_less_than() is deprecated because it is stochastic and unreliable",
-    call. = FALSE
+  cli::cli_warn(
+    "{.fn takes_less_than} is deprecated because it is stochastic and unreliable."
   )
 
   function(expr) {
@@ -165,7 +164,7 @@ takes_less_than <- function(amount) {
 #' @keywords internal
 #' @export
 not <- function(f) {
-  warning("`not()` is deprecated.", call. = FALSE)
+  cli::cli_warn("{.fn not} is deprecated.")
   stopifnot(is.function(f))
 
   negate <- function(expt) {
diff --git a/R/parallel-config.R b/R/parallel-config.R
index 1082e4c54..1c3b4133f 100644
--- a/R/parallel-config.R
+++ b/R/parallel-config.R
@@ -8,7 +8,9 @@ find_parallel <- function(path, load_package = "source", package = NULL) {
     if (toupper(parenv) == "FALSE") {
       return(FALSE)
     }
-    abort("`TESTTHAT_PARALLEL` must be `TRUE` or `FALSE`")
+    cli::cli_abort(
+      "{.envvar TESTTHAT_PARALLEL} must be {.code TRUE} or {.code FALSE}."
+    )
   }
 
   # Make sure we get the local package package if not "installed"
@@ -28,7 +30,7 @@ find_parallel <- function(path, load_package = "source", package = NULL) {
   if (par) {
     ed <- as.integer(desc$get_field("Config/testthat/edition", default = 2L))
     if (ed < 3) {
-      inform("Running tests in parallel requires the 3rd edition")
+      cli::cli_inform("Running tests in parallel requires the 3rd edition.")
       par <- FALSE
     }
   }
diff --git a/R/parallel-taskq.R b/R/parallel-taskq.R
index 6e903064c..22300ce8b 100644
--- a/R/parallel-taskq.R
+++ b/R/parallel-taskq.R
@@ -40,7 +40,7 @@ task_q <- R6::R6Class(
         id <- private$get_next_id()
       }
       if (id %in% private$tasks$id) {
-        stop("Duplicate task id")
+        cli::cli_abort("Duplicate task id.")
       }
       before <- which(private$tasks$idle)[1]
       private$tasks <- df_add_row(
@@ -123,16 +123,11 @@ task_q <- R6::R6Class(
             private$handle_error(msg, i)
           } else {
             file <- private$tasks$args[[i]][[1]]
-            errmsg <- paste0(
-              "unknown message from testthat subprocess: ",
-              msg$code,
-              ", ",
-              "in file `",
-              file,
-              "`"
-            )
-            abort(
-              errmsg,
+            cli::cli_abort(
+              c(
+                "Unknown message from testthat subprocess: {msg$code}.",
+                "i" = "In file {.file {file}}."
+              ),
               test_file = file,
               class = c("testthat_process_error", "testthat_error")
             )
@@ -211,7 +206,7 @@ task_q <- R6::R6Class(
     },
 
     handle_error = function(msg, task_no) {
-      inform("\n") # get out of the progress bar, if any
+      cat("\n") # get out of the progress bar, if any
       fun <- private$tasks$fun[[task_no]]
       file <- private$tasks$args[[task_no]][[1]]
       if (is.null(fun)) {
@@ -220,21 +215,22 @@ task_q <- R6::R6Class(
           c(private$tasks$startup[[task_no]], msg$stderr),
           collapse = "\n"
         )
-        abort(
-          paste0(
-            "testthat subprocess failed to start, stderr:\n",
-            msg$error$stderr
+        cli::cli_abort(
+          c(
+            "testthat subprocess failed to start.",
+            " " = "{no_wrap(msg$error$stderr)}"
           ),
           test_file = NULL,
-          parent = msg$error,
-          class = c("testthat_process_error", "testthat_error")
+          class = c("testthat_process_error", "testthat_error"),
+          call = NULL
         )
       } else {
-        abort(
-          paste0("testthat subprocess exited in file `", file, "`"),
+        cli::cli_abort(
+          "testthat subprocess exited in file {.file {file}}.",
           test_file = file,
           parent = msg$error,
-          class = c("testthat_process_error", "testthat_error")
+          class = c("testthat_process_error", "testthat_error"),
+          call = NULL
         )
       }
     }
diff --git a/R/parallel.R b/R/parallel.R
index 0445e50a9..cd07b4e10 100644
--- a/R/parallel.R
+++ b/R/parallel.R
@@ -46,12 +46,7 @@ test_files_parallel <- function(
   # TODO: support timeouts. 20-30s for each file by default?
 
   num_workers <- min(default_num_cpus(), length(test_paths))
-  inform(paste0(
-    "Starting ",
-    num_workers,
-    " test process",
-    if (num_workers != 1) "es"
-  ))
+  cli::cli_inform("Starting {num_workers} test process{?es}.")
 
   # Set up work queue ------------------------------------------
   queue <- NULL
@@ -110,7 +105,10 @@ default_num_cpus <- function() {
   if (!is.null(ncpus)) {
     ncpus <- suppressWarnings(as.integer(ncpus))
     if (is.na(ncpus)) {
-      abort("`getOption(Ncpus)` must be an integer")
+      cli::cli_abort(
+        "{.code getOption('Ncpus')} must be an integer.",
+        call = NULL
+      )
     }
     return(ncpus)
   }
@@ -120,7 +118,7 @@ default_num_cpus <- function() {
   if (ncpus != "") {
     ncpus <- suppressWarnings(as.integer(ncpus))
     if (is.na(ncpus)) {
-      abort("TESTTHAT_CPUS must be an integer")
+      cli::cli_abort("{.envvar TESTTHAT_CPUS} must be an integer.")
     }
     return(ncpus)
   }
@@ -155,7 +153,7 @@ parallel_event_loop_smooth <- function(queue, reporters, test_dir) {
 
       m <- x$message
       if (!inherits(m, "testthat_message")) {
-        message(m)
+        cli::cli_inform(as.character(m))
         next
       }
 
@@ -195,7 +193,7 @@ parallel_event_loop_chunky <- function(queue, reporters, test_dir) {
 
       m <- x$message
       if (!inherits(m, "testthat_message")) {
-        message(m)
+        cli::cli_inform(as.character(m))
         next
       }
 
diff --git a/R/reporter-fail.R b/R/reporter-fail.R
index 2649a85a7..c5f6192ee 100644
--- a/R/reporter-fail.R
+++ b/R/reporter-fail.R
@@ -23,7 +23,7 @@ FailReporter <- R6::R6Class(
 
     end_reporter = function() {
       if (self$failed) {
-        stop("Failures detected.", call. = FALSE)
+        cli::cli_abort("Failures detected.")
       }
     }
   )
diff --git a/R/reporter-junit.R b/R/reporter-junit.R
index acb28adbb..12442f894 100644
--- a/R/reporter-junit.R
+++ b/R/reporter-junit.R
@@ -166,7 +166,7 @@ JunitReporter <- R6::R6Class(
         xml2::write_xml(self$doc, file, format = TRUE)
         cat(brio::read_file(file), file = self$out)
       } else {
-        stop("unsupported output type: ", toString(self$out))
+        cli::cli_abort("Unsupported output type: {toString(self$out)}.")
       }
     } # end_reporter
   ), # public
diff --git a/R/reporter-stop.R b/R/reporter-stop.R
index b24500eaa..bf73bdc54 100644
--- a/R/reporter-stop.R
+++ b/R/reporter-stop.R
@@ -64,7 +64,7 @@ StopReporter <- R6::R6Class(
 
     stop_if_needed = function() {
       if (self$stop_reporter && self$n_fail > 0) {
-        abort("Test failed", call = NULL)
+        cli::cli_abort("Test failed.")
       }
     }
   )
diff --git a/R/reporter-zzz.R b/R/reporter-zzz.R
index c67eecb95..e14ee09a4 100644
--- a/R/reporter-zzz.R
+++ b/R/reporter-zzz.R
@@ -85,26 +85,31 @@ find_reporter <- function(reporter) {
     reporter$new()
   } else if (inherits(reporter, "Reporter")) {
     reporter
+  } else if (is_string(reporter)) {
+    find_reporter_one(reporter)
   } else if (is.character(reporter)) {
-    if (length(reporter) <= 1L) {
-      find_reporter_one(reporter)
-    } else {
-      MultiReporter$new(reporters = lapply(reporter, find_reporter_one))
-    }
+    reporters <- lapply(reporter, find_reporter_one, call = current_env())
+    MultiReporter$new(reporters)
   } else {
-    stop("Invalid input", call. = FALSE)
+    stop_input_type(
+      reporter,
+      c(
+        "a string",
+        "a character vector",
+        "a reporter object",
+        "a reporter class"
+      )
+    )
   }
 }
 
-find_reporter_one <- function(reporter, ...) {
-  check_string(reporter)
-
+find_reporter_one <- function(reporter, ..., call = caller_env()) {
   name <- reporter
   substr(name, 1, 1) <- toupper(substr(name, 1, 1))
   name <- paste0(name, "Reporter")
 
   if (!exists(name)) {
-    stop("Can not find test reporter ", reporter, call. = FALSE)
+    cli::cli_abort("Cannot find test reporter {.arg {reporter}}.", call = call)
   }
 
   get(name)$new(...)
diff --git a/R/skip.R b/R/skip.R
index 6214da355..b085db721 100644
--- a/R/skip.R
+++ b/R/skip.R
@@ -217,7 +217,7 @@ skip_on_os <- function(os, arch = NULL) {
 
   if (!is.null(arch) && !is.null(msg)) {
     if (!is.character(arch)) {
-      abort("`arch` must be a character vector")
+      cli::cli_abort("{.arg arch} must be a character vector.")
     }
 
     if (system_arch() %in% arch) {
diff --git a/R/snapshot-cleanup.R b/R/snapshot-cleanup.R
index 0dd92fdb0..dbd4440dd 100644
--- a/R/snapshot-cleanup.R
+++ b/R/snapshot-cleanup.R
@@ -6,7 +6,7 @@ snapshot_cleanup <- function(
   outdated <- snapshot_outdated(path, test_files_seen, snap_files_seen)
 
   if (length(outdated) > 0) {
-    inform(c("Deleting unused snapshots:", outdated))
+    cli::cli_inform("Deleting unused snapshots: {.path {outdated}}")
     unlink(file.path(path, outdated), recursive = TRUE)
   }
 
diff --git a/R/snapshot-file.R b/R/snapshot-file.R
index dda23e068..3dc32c2b3 100644
--- a/R/snapshot-file.R
+++ b/R/snapshot-file.R
@@ -200,7 +200,7 @@ snapshot_file_equal <- function(
   trace_env = caller_env()
 ) {
   if (!file.exists(path)) {
-    abort(paste0("`", path, "` not found"))
+    cli::cli_abort("{.path {path}} not found.")
   }
 
   if (is.null(snap_variant)) {
diff --git a/R/snapshot-manage.R b/R/snapshot-manage.R
index c843f9046..89f0021d7 100644
--- a/R/snapshot-manage.R
+++ b/R/snapshot-manage.R
@@ -15,11 +15,11 @@
 snapshot_accept <- function(files = NULL, path = "tests/testthat") {
   changed <- snapshot_meta(files, path)
   if (nrow(changed) == 0) {
-    inform("No snapshots to update")
+    cli::cli_inform("No snapshots to update.")
     return(invisible())
   }
 
-  inform(c("Updating snapshots:", changed$name))
+  cli::cli_inform("Updating snapshots: {.path {changed$name}}.")
   unlink(changed$cur)
   file.rename(changed$new, changed$cur)
 
@@ -50,7 +50,7 @@ snapshot_review <- function(files = NULL, path = "tests/testthat") {
 
   changed <- snapshot_meta(files, path)
   if (nrow(changed) == 0) {
-    inform("No snapshots to update")
+    cli::cli_inform("No snapshots to update.")
     return(invisible())
   }
 
@@ -97,12 +97,12 @@ review_app <- function(name, old_path, new_path) {
     # Handle buttons - after clicking update move input$cases to next case,
     # and remove current case (for accept/reject). If no cases left, close app
     shiny::observeEvent(input$reject, {
-      inform(paste0("Rejecting snapshot: '", new_path[[i()]], "'"))
+      cli::cli_inform("Rejecting snapshot: {.path {new_path[[i()]]}}.")
       unlink(new_path[[i()]])
       update_cases()
     })
     shiny::observeEvent(input$accept, {
-      inform(paste0("Accepting snapshot: '", old_path[[i()]], "'"))
+      cli::cli_inform("Accepting snapshot: {.path {old_path[[i()]]}}.")
       file.rename(new_path[[i()]], old_path[[i()]])
       update_cases()
     })
@@ -124,7 +124,7 @@ review_app <- function(name, old_path, new_path) {
     }
     next_case <- function() {
       if (all(handled)) {
-        inform("Review complete")
+        cli::cli_inform("Review complete.")
         shiny::stopApp()
         return()
       }
@@ -140,9 +140,9 @@ review_app <- function(name, old_path, new_path) {
     }
   }
 
-  inform(c(
-    "Starting Shiny app for snapshot review",
-    i = "Use Ctrl + C to quit"
+  cli::cli_inform(c(
+    "Starting Shiny app for snapshot review.",
+    i = "Use {.kbd Ctrl + C} to quit."
   ))
   shiny::runApp(
     shiny::shinyApp(ui, server),
diff --git a/R/snapshot-reporter.R b/R/snapshot-reporter.R
index cd1b3e673..c226518ff 100644
--- a/R/snapshot-reporter.R
+++ b/R/snapshot-reporter.R
@@ -205,7 +205,7 @@ local_snapshotter <- function(
     fail_on_new = fail_on_new
   )
   if (!identical(cleanup, FALSE)) {
-    warn("`cleanup` is deprecated")
+    cli::cli_warn("{.arg cleanup} is deprecated.")
   }
 
   withr::local_options(
diff --git a/R/snapshot-value.R b/R/snapshot-value.R
index 0e0864219..c14026af2 100644
--- a/R/snapshot-value.R
+++ b/R/snapshot-value.R
@@ -116,21 +116,11 @@ check_roundtrip <- function(
     tolerance = tolerance
   )
   if (length(check) > 0) {
-    abort(
+    cli::cli_abort(
       c(
-        paste0(
-          "`",
-          label,
-          "` could not be safely serialized with `style = \"",
-          style,
-          "\"`."
-        ),
-        " " = paste0(
-          "Serializing then deserializing the object returned something new:\n\n",
-          check,
-          "\n"
-        ),
-        i = "You may need to try a different `style`."
+        "{.code {label}} could not be safely serialized with {.arg style} = {.str {style}}.",
+        " " = "Serializing then deserializing the object returned something new:\n\n{no_wrap(check)}\n",
+        i = "You may need to try a different {.arg style}."
       ),
       call = error_call
     )
diff --git a/R/snapshot.R b/R/snapshot.R
index 40f39b547..4e016c897 100644
--- a/R/snapshot.R
+++ b/R/snapshot.R
@@ -408,13 +408,13 @@ local_snapshot_dir <- function(snap_names, .env = parent.frame()) {
 # if transform() wiped out the full message, don't indent, #1487
 indent <- function(x) if (length(x)) paste0("  ", x) else x
 
-check_variant <- function(x) {
+check_variant <- function(x, call = caller_env()) {
   if (is.null(x)) {
     "_default"
   } else if (is_string(x)) {
     x
   } else {
-    abort("If supplied, `variant` must be a string")
+    cli::cli_abort("If supplied, {.arg variant} must be a string.", call = call)
   }
 }
 
diff --git a/R/source.R b/R/source.R
index bfc8733ef..e13f6247a 100644
--- a/R/source.R
+++ b/R/source.R
@@ -63,8 +63,8 @@ source_file <- function(
     withCallingHandlers(
       invisible(eval(exprs, env)),
       error = function(err) {
-        abort(
-          paste0("In path: ", encodeString(path, quote = '"')),
+        cli::cli_abort(
+          "Failed to evaluate {.path {path}}.",
           parent = err,
           call = error_call
         )
@@ -99,8 +99,8 @@ filter_desc <- function(exprs, desc = NULL, error_call = caller_env()) {
       }
 
       if (found) {
-        abort(
-          "Found multiple tests with specified description",
+        cli::cli_abort(
+          "Found multiple tests with specified description.",
           call = error_call
         )
       }
@@ -110,7 +110,10 @@ filter_desc <- function(exprs, desc = NULL, error_call = caller_env()) {
   }
 
   if (!found) {
-    abort("Failed to find test with specified description", call = error_call)
+    cli::cli_abort(
+      "Failed to find test with specified description.",
+      call = error_call
+    )
   }
 
   exprs[include]
@@ -125,9 +128,17 @@ source_dir <- function(
   chdir = TRUE,
   wrap = TRUE
 ) {
-  files <- normalizePath(sort(dir(path, pattern, full.names = TRUE)))
+  files <- sort(dir(path, pattern, full.names = TRUE))
+
+  error_call <- current_env()
   lapply(files, function(path) {
-    source_file(path, env = env, chdir = chdir, wrap = wrap)
+    source_file(
+      path,
+      env = env,
+      chdir = chdir,
+      wrap = wrap,
+      error_call = error_call
+    )
   })
 }
 
diff --git a/R/srcrefs.R b/R/srcrefs.R
index 82934b627..bb9067281 100644
--- a/R/srcrefs.R
+++ b/R/srcrefs.R
@@ -72,13 +72,13 @@ sys_index <- function(bottom = NULL, top = caller_env()) {
   } else {
     bottom_idx <- Position(function(env) identical(bottom, env), frames)
     if (is.na(bottom_idx)) {
-      abort("Can't find `bottom` on stack")
+      cli::cli_abort("Can't find {.arg bottom} on stack.")
     }
   }
 
   top_idx <- Position(function(env) identical(top, env), frames)
   if (is.na(top_idx)) {
-    abort("Can't find `top` on stack")
+    cli::cli_abort("Can't find {.arg top} on stack.")
   }
 
   seq2(bottom_idx, top_idx)
diff --git a/R/test-compiled-code.R b/R/test-compiled-code.R
index 6e1ee902d..5593288af 100644
--- a/R/test-compiled-code.R
+++ b/R/test-compiled-code.R
@@ -14,10 +14,9 @@ expect_cpp_tests_pass <- function(package) {
       tests_passed <- .Call(run_testthat_tests, FALSE)
     ),
     error = function(e) {
-      warning(sprintf(
-        "failed to call test entrypoint '%s'",
-        run_testthat_tests
-      ))
+      cli::cli_warn(
+        "Failed to call test entrypoint {.fn {run_testthat_tests}}."
+      )
     }
   )
 
@@ -324,23 +323,20 @@ run_cpp_tests <- function(package) {
 use_catch <- function(dir = getwd()) {
   desc_path <- file.path(dir, "DESCRIPTION")
   if (!file.exists(desc_path)) {
-    stop("no DESCRIPTION file at path '", desc_path, "'", call. = FALSE)
+    cli::cli_abort("No DESCRIPTION file at path {.path {desc_path}}.")
   }
 
   desc <- read.dcf(desc_path, all = TRUE)
   pkg <- desc$Package
   if (!nzchar(pkg)) {
-    stop(
-      "no 'Package' field in DESCRIPTION file '",
-      desc_path,
-      "'",
-      call. = FALSE
+    cli::cli_abort(
+      "No {.field Package} field in DESCRIPTION file {.path {desc_path}}."
     )
   }
 
   src_dir <- file.path(dir, "src")
   if (!file.exists(src_dir) && !dir.create(src_dir)) {
-    stop("failed to create 'src/' directory '", src_dir, "'", call. = FALSE)
+    cli::cli_abort("Failed to create {.path src/} directory {.path {src_dir}}.")
   }
 
   test_runner_path <- file.path(src_dir, "test-runner.cpp")
@@ -353,7 +349,9 @@ use_catch <- function(dir = getwd()) {
   )
 
   if (!success) {
-    stop("failed to copy 'test-runner.cpp' to '", src_dir, "'", call. = FALSE)
+    cli::cli_abort(
+      "Failed to copy {.file test-runner.cpp} to {.path {src_dir}}."
+    )
   }
 
   # Copy the test example.
@@ -364,17 +362,16 @@ use_catch <- function(dir = getwd()) {
   )
 
   if (!success) {
-    stop("failed to copy 'test-example.cpp' to '", src_dir, "'", call. = FALSE)
+    cli::cli_abort(
+      "Failed to copy {.file test-example.cpp} to {.path {src_dir}}."
+    )
   }
 
   # Copy the 'test-cpp.R' file.
   test_dir <- file.path(dir, "tests", "testthat")
   if (!file.exists(test_dir) && !dir.create(test_dir, recursive = TRUE)) {
-    stop(
-      "failed to create 'tests/testthat/' directory '",
-      test_dir,
-      "'",
-      call. = FALSE
+    cli::cli_abort(
+      "Failed to create {.path tests/testthat/} directory {.path {test_dir}}."
     )
   }
 
@@ -395,14 +392,11 @@ use_catch <- function(dir = getwd()) {
   output_path <- file.path(dir, "R", "catch-routine-registration.R")
   cat(transformed, file = output_path)
 
-  message("> Added C++ unit testing infrastructure.")
-  message("> Please ensure you have 'LinkingTo: testthat' in your DESCRIPTION.")
-  message("> Please ensure you have 'Suggests: xml2' in your DESCRIPTION.")
-  message(
-    "> Please ensure you have 'useDynLib(",
-    pkg,
-    ", .registration = TRUE)' in your NAMESPACE."
-  )
+  cli::cli_inform(c(
+    v = "Added C++ unit testing infrastructure.",
+    i = "Please ensure you have {.field LinkingTo: testthat} in your DESCRIPTION.",
+    i = "Please ensure you have {.field Suggests: xml2} in your DESCRIPTION."
+  ))
 }
 
 get_routine <- function(package, routine) {
@@ -435,8 +429,9 @@ get_routine <- function(package, routine) {
   }
 
   # if we got here, we failed to find the symbol -- throw an error
-  fmt <- "failed to locate routine '%s' in package '%s'"
-  stop(sprintf(fmt, routine, package), call. = FALSE)
+  cli::cli_abort(
+    "Failed to locate routine {.code {routine}} in package {.pkg {package}}."
+  )
 }
 
 (function() {
diff --git a/R/test-example.R b/R/test-example.R
index b80f229c8..d994b5b70 100644
--- a/R/test-example.R
+++ b/R/test-example.R
@@ -15,7 +15,7 @@
 test_examples <- function(path = "../..") {
   res <- test_examples_source(path) %||% test_examples_installed()
   if (is.null(res)) {
-    stop("Could not find examples", call. = FALSE)
+    cli::cli_abort("Could not find examples.")
   }
   invisible(res)
 }
diff --git a/R/test-files.R b/R/test-files.R
index cdb6f802e..eb67f6fce 100644
--- a/R/test-files.R
+++ b/R/test-files.R
@@ -65,7 +65,7 @@ test_dir <- function(
     start_first = start_first
   )
   if (length(test_paths) == 0) {
-    abort("No test files found")
+    cli::cli_abort("No test files found.")
   }
 
   if (!is_missing(wrap)) {
@@ -123,7 +123,7 @@ test_file <- function(
   ...
 ) {
   if (!file.exists(path)) {
-    stop("`path` does not exist", call. = FALSE)
+    cli::cli_abort("{.arg path} does not exist.")
   }
 
   test_files(
@@ -273,7 +273,7 @@ find_load_all_args <- function(path) {
 
   args <- parse_expr(args)
   if (!is_call(args, "list")) {
-    abort("`Config/testthat/load-all` must be a list.", call = NULL)
+    cli::cli_abort("{.field Config/testthat/load-all} must be a list.")
   }
 
   args <- as.list(args[-1])
@@ -325,10 +325,10 @@ test_files_check <- function(
   stop_on_warning = FALSE
 ) {
   if (stop_on_failure && !all_passed(results)) {
-    stop("Test failures", call. = FALSE)
+    cli::cli_abort("Test failures.")
   }
   if (stop_on_warning && any_warnings(results)) {
-    stop("Tests generated warnings", call. = FALSE)
+    cli::cli_abort("Tests generated warnings.")
   }
 
   invisible(results)
@@ -366,7 +366,10 @@ test_one_file <- function(
 #' @export
 teardown_env <- function() {
   if (is.null(the$teardown_env)) {
-    abort("`teardown_env()` has not been initialized", .internal = TRUE)
+    cli::cli_abort(
+      "{.fn teardown_env} has not been initialized.",
+      .internal = TRUE
+    )
   }
 
   the$teardown_env
diff --git a/R/test-package.R b/R/test-package.R
index 90154a6c5..d0f7f435a 100644
--- a/R/test-package.R
+++ b/R/test-package.R
@@ -27,7 +27,7 @@
 test_package <- function(package, reporter = check_reporter(), ...) {
   test_path <- system.file("tests", "testthat", package = package)
   if (test_path == "") {
-    inform(paste0("No installed testthat tests found for ", package))
+    cli::cli_inform("No installed testthat tests found for {.pkg {package}}.")
     return(invisible())
   }
 
diff --git a/R/test-that.R b/R/test-that.R
index e214bd877..a08782dec 100644
--- a/R/test-that.R
+++ b/R/test-that.R
@@ -39,8 +39,8 @@ test_that <- function(desc, code) {
   code <- substitute(code)
   if (edition_get() >= 3) {
     if (!is_call(code, "{")) {
-      warn(
-        "The `code` argument to `test_that()` must be a braced expression to get accurate file-line information for failures.",
+      cli::cli_warn(
+        "The {.arg code} argument to {.fn test_that} must be a braced expression to get accurate file-line information for failures.",
         class = "testthat_braces_warning"
       )
     }
diff --git a/R/utils.R b/R/utils.R
index 868c46574..2b7a402f8 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -57,6 +57,13 @@ in_rcmd_check <- function() {
 
 r_version <- function() paste0("R", getRversion()[, 1:2])
 
+# Supress cli wrapping
+no_wrap <- function(x) {
+  x <- gsub(" ", "\u00a0", x, fixed = TRUE)
+  x <- gsub("\n", "\f", x, fixed = TRUE)
+  x
+}
+
 paste_c <- function(...) {
   paste0(c(...), collapse = "")
 }
diff --git a/R/verify-output.R b/R/verify-output.R
index 2e3aa3327..99f7af1de 100644
--- a/R/verify-output.R
+++ b/R/verify-output.R
@@ -167,7 +167,7 @@ output_replay.message <- function(x) {
 
 #' @export
 output_replay.recordedplot <- function(x) {
-  abort("Plots are not supported")
+  cli::cli_abort("Plots are not supported.")
 }
 
 
diff --git a/tests/testthat/_snaps/examples.md b/tests/testthat/_snaps/examples.md
index ad79089ce..894721ebb 100644
--- a/tests/testthat/_snaps/examples.md
+++ b/tests/testthat/_snaps/examples.md
@@ -3,6 +3,6 @@
     Code
       test_examples("asdf")
     Condition
-      Error:
-      ! Could not find examples
+      Error in `test_examples()`:
+      ! Could not find examples.
 
diff --git a/tests/testthat/_snaps/expect-comparison.md b/tests/testthat/_snaps/expect-comparison.md
index 8b7000271..e204dd779 100644
--- a/tests/testthat/_snaps/expect-comparison.md
+++ b/tests/testthat/_snaps/expect-comparison.md
@@ -24,5 +24,5 @@
       expect_lt(1:10, 5)
     Condition
       Error in `expect_lt()`:
-      ! Result of comparison must be a single logical value
+      ! Result of comparison must be a single logical value.
 
diff --git a/tests/testthat/_snaps/parallel.md b/tests/testthat/_snaps/parallel.md
new file mode 100644
index 000000000..07184d68b
--- /dev/null
+++ b/tests/testthat/_snaps/parallel.md
@@ -0,0 +1,8 @@
+# good error if bad option
+
+    Code
+      default_num_cpus()
+    Condition
+      Error:
+      ! `getOption('Ncpus')` must be an integer.
+
diff --git a/tests/testthat/_snaps/reporter-stop.md b/tests/testthat/_snaps/reporter-stop.md
index febb63df5..24210c492 100644
--- a/tests/testthat/_snaps/reporter-stop.md
+++ b/tests/testthat/_snaps/reporter-stop.md
@@ -53,6 +53,6 @@
     Code
       r$stop_if_needed()
     Condition
-      Error:
-      ! Test failed
+      Error in `r$stop_if_needed()`:
+      ! Test failed.
 
diff --git a/tests/testthat/_snaps/reporter-zzz.md b/tests/testthat/_snaps/reporter-zzz.md
index dbe7b5c13..f1d7b49b0 100644
--- a/tests/testthat/_snaps/reporter-zzz.md
+++ b/tests/testthat/_snaps/reporter-zzz.md
@@ -1,8 +1,18 @@
 # useful error message if can't find reporter
 
+    Code
+      find_reporter(1)
+    Condition
+      Error in `find_reporter()`:
+      ! `reporter` must be a string, a character vector, a reporter object, or a reporter class, not the number 1.
+    Code
+      find_reporter("blah")
+    Condition
+      Error in `find_reporter()`:
+      ! Cannot find test reporter `blah`.
     Code
       find_reporter(c("summary", "blah"))
     Condition
-      Error:
-      ! Can not find test reporter blah
+      Error in `find_reporter()`:
+      ! Cannot find test reporter `blah`.
 
diff --git a/tests/testthat/_snaps/snapshot-cleanup.md b/tests/testthat/_snaps/snapshot-cleanup.md
index 218619ea1..05b0f5ac6 100644
--- a/tests/testthat/_snaps/snapshot-cleanup.md
+++ b/tests/testthat/_snaps/snapshot-cleanup.md
@@ -3,9 +3,7 @@
     Code
       snapshot_cleanup(dir)
     Message
-      Deleting unused snapshots:
-      * a.md
-      * b.md
+      Deleting unused snapshots: 'a.md' and 'b.md'
     Code
       snapshot_cleanup(dir, c("a", "b"))
 
diff --git a/tests/testthat/_snaps/snapshot-file.md b/tests/testthat/_snaps/snapshot-file.md
index e36419766..33f271748 100644
--- a/tests/testthat/_snaps/snapshot-file.md
+++ b/tests/testthat/_snaps/snapshot-file.md
@@ -12,7 +12,7 @@
       snapshot_file_equal_("doesnt-exist.txt")
     Condition
       Error in `snapshot_file_equal()`:
-      ! `doesnt-exist.txt` not found
+      ! 'doesnt-exist.txt' not found.
 
 # snapshot_hint output differs in R CMD check
 
diff --git a/tests/testthat/_snaps/snapshot-manage.md b/tests/testthat/_snaps/snapshot-manage.md
index d6dad619d..2b5b02f6b 100644
--- a/tests/testthat/_snaps/snapshot-manage.md
+++ b/tests/testthat/_snaps/snapshot-manage.md
@@ -3,56 +3,49 @@
     Code
       snapshot_accept(path = path)
     Message
-      Updating snapshots:
-      * a.md
-      * b.md
+      Updating snapshots: 'a.md' and 'b.md'.
 
 ---
 
     Code
       snapshot_accept(path = path)
     Message
-      No snapshots to update
+      No snapshots to update.
 
 # can accept specific files
 
     Code
       snapshot_accept("a", path = path)
     Message
-      Updating snapshots:
-      * a.md
+      Updating snapshots: 'a.md'.
 
 ---
 
     Code
       snapshot_accept("test/a.txt", path = path)
     Message
-      Updating snapshots:
-      * test/a.txt
+      Updating snapshots: 'test/a.txt'.
 
 ---
 
     Code
       snapshot_accept("test/", path = path)
     Message
-      Updating snapshots:
-      * test/a.txt
+      Updating snapshots: 'test/a.txt'.
 
 # can work with variants
 
     Code
       snapshot_accept(path = path)
     Message
-      Updating snapshots:
-      * foo/a.md
+      Updating snapshots: 'foo/a.md'.
 
 ---
 
     Code
       snapshot_accept("foo/a", path = path)
     Message
-      Updating snapshots:
-      * foo/a.md
+      Updating snapshots: 'foo/a.md'.
 
 # snapshot_reject deletes .new files
 
diff --git a/tests/testthat/_snaps/snapshot-value.md b/tests/testthat/_snaps/snapshot-value.md
index 540b60dc9..70ab96884 100644
--- a/tests/testthat/_snaps/snapshot-value.md
+++ b/tests/testthat/_snaps/snapshot-value.md
@@ -75,12 +75,11 @@
       wrapper(NULL, list(), label = "foo", style = "json")
     Condition
       Error in `wrapper()`:
-      ! `foo` could not be safely serialized with `style = "json"`.
+      ! `foo` could not be safely serialized with `style` = "json".
         Serializing then deserializing the object returned something new:
-      
-      `original` is NULL
-      `new` is a list
-      
+        
+        `original` is NULL
+        `new` is a list
       i You may need to try a different `style`.
 
 # expect_snapshot_value validates its inputs
diff --git a/tests/testthat/_snaps/source.md b/tests/testthat/_snaps/source.md
index 48519c770..1e4b57049 100644
--- a/tests/testthat/_snaps/source.md
+++ b/tests/testthat/_snaps/source.md
@@ -4,7 +4,7 @@
       source_file(test_path("reporters/error-setup.R"), wrap = FALSE)
     Condition
       Error:
-      ! In path: "reporters/error-setup.R"
+      ! Failed to evaluate 'reporters/error-setup.R'.
       Caused by error in `h()`:
       ! !
 
@@ -32,7 +32,7 @@
       filter_desc(code, "baz")
     Condition
       Error:
-      ! Failed to find test with specified description
+      ! Failed to find test with specified description.
 
 # preserve srcrefs
 
@@ -49,5 +49,5 @@
       filter_desc(code, "baz")
     Condition
       Error:
-      ! Found multiple tests with specified description
+      ! Found multiple tests with specified description.
 
diff --git a/tests/testthat/_snaps/test-compiled-code.md b/tests/testthat/_snaps/test-compiled-code.md
index 67f4c2e43..60c213e46 100644
--- a/tests/testthat/_snaps/test-compiled-code.md
+++ b/tests/testthat/_snaps/test-compiled-code.md
@@ -3,8 +3,8 @@
     Code
       get_routine("utils", "no_such_routine")
     Condition
-      Error:
-      ! failed to locate routine 'no_such_routine' in package 'utils'
+      Error in `get_routine()`:
+      ! Failed to locate routine `no_such_routine` in package utils.
 
 # validates inputs
 
@@ -19,3 +19,12 @@
       Error in `run_cpp_tests()`:
       ! `package` must be a single string, not the number 123.
 
+# useful messaging
+
+    Code
+      use_catch(path)
+    Message
+      v Added C++ unit testing infrastructure.
+      i Please ensure you have LinkingTo: testthat in your DESCRIPTION.
+      i Please ensure you have Suggests: xml2 in your DESCRIPTION.
+
diff --git a/tests/testthat/_snaps/test-files.md b/tests/testthat/_snaps/test-files.md
index e23707c0c..9f5c6fdc7 100644
--- a/tests/testthat/_snaps/test-files.md
+++ b/tests/testthat/_snaps/test-files.md
@@ -3,8 +3,8 @@
     Code
       test_dir(test_path("test_dir"), reporter = "silent")
     Condition
-      Error:
-      ! Test failures
+      Error in `test_files_check()`:
+      ! Test failures.
 
 # runs all tests and records output
 
@@ -33,29 +33,29 @@
       test_dir(path)
     Condition
       Error in `test_dir()`:
-      ! No test files found
+      ! No test files found.
 
 # can control if failures generate errors
 
     Code
       test_error(stop_on_failure = TRUE)
     Condition
-      Error:
-      ! Test failures
+      Error in `test_files_check()`:
+      ! Test failures.
 
 # can control if warnings errors
 
     Code
       test_warning(stop_on_warning = TRUE)
     Condition
-      Error:
-      ! Tests generated warnings
+      Error in `test_files_check()`:
+      ! Tests generated warnings.
 
 # complains if file doesn't exist
 
     Code
       test_file("DOESNTEXIST")
     Condition
-      Error:
-      ! `path` does not exist
+      Error in `test_file()`:
+      ! `path` does not exist.
 
diff --git a/tests/testthat/_snaps/verify-output.md b/tests/testthat/_snaps/verify-output.md
index 222181b75..c0ae6c22c 100644
--- a/tests/testthat/_snaps/verify-output.md
+++ b/tests/testthat/_snaps/verify-output.md
@@ -4,5 +4,5 @@
       verify_output(tempfile(), plot(1:10))
     Condition
       Error in `FUN()`:
-      ! Plots are not supported
+      ! Plots are not supported.
 
diff --git a/tests/testthat/test-parallel-setup.R b/tests/testthat/test-parallel-setup.R
index f8bfdefb6..2eff8a4d1 100644
--- a/tests/testthat/test-parallel-setup.R
+++ b/tests/testthat/test-parallel-setup.R
@@ -9,5 +9,5 @@ test_that("error in parallel setup code", {
     error = function(e) e
   )
   expect_s3_class(err, "testthat_process_error")
-  expect_match(err$message, "Error in setup", fixed = TRUE)
+  expect_match(conditionMessage(err), "Error in setup", fixed = TRUE)
 })
diff --git a/tests/testthat/test-parallel-startup.R b/tests/testthat/test-parallel-startup.R
index b2ea8a8f6..240aeff1d 100644
--- a/tests/testthat/test-parallel-startup.R
+++ b/tests/testthat/test-parallel-startup.R
@@ -9,5 +9,5 @@ test_that("startup error", {
     error = function(e) e
   )
   expect_s3_class(err, "testthat_process_error")
-  expect_match(err$message, "This will fail", fixed = TRUE)
+  expect_match(conditionMessage(err), "This will fail", fixed = TRUE)
 })
diff --git a/tests/testthat/test-parallel.R b/tests/testthat/test-parallel.R
index 2d4c97734..9e6bd1111 100644
--- a/tests/testthat/test-parallel.R
+++ b/tests/testthat/test-parallel.R
@@ -20,6 +20,11 @@ test_that("detect number of cpus to use", {
   expect_equal(default_num_cpus(), 13L)
 })
 
+test_that("good error if bad option", {
+  withr::local_options(Ncpus = "bad")
+  expect_snapshot(default_num_cpus(), error = TRUE)
+})
+
 test_that("ok", {
   withr::local_envvar(c(TESTTHAT_PARALLEL = "TRUE"))
   # we cannot run these with the silent reporter, because it is not
diff --git a/tests/testthat/test-parallel/startup/R/fail.R b/tests/testthat/test-parallel/startup/R/fail.R
index 8f6684c3a..702d692ba 100644
--- a/tests/testthat/test-parallel/startup/R/fail.R
+++ b/tests/testthat/test-parallel/startup/R/fail.R
@@ -1,3 +1,3 @@
 .onLoad <- function(libname, pkgname) {
-  stop("This will fail when loading the package")
+  stop("This will fail when loading the package", call. = FALSE)
 }
diff --git a/tests/testthat/test-reporter-zzz.R b/tests/testthat/test-reporter-zzz.R
index 6bbf9c1a1..4ac112a28 100644
--- a/tests/testthat/test-reporter-zzz.R
+++ b/tests/testthat/test-reporter-zzz.R
@@ -5,6 +5,8 @@ test_that("can locate reporter from name", {
 
 test_that("useful error message if can't find reporter", {
   expect_snapshot(error = TRUE, {
+    find_reporter(1)
+    find_reporter("blah")
     find_reporter(c("summary", "blah"))
   })
 })
diff --git a/tests/testthat/test-test-compiled-code.R b/tests/testthat/test-test-compiled-code.R
index d9fba9b2b..c60e0dd8a 100644
--- a/tests/testthat/test-test-compiled-code.R
+++ b/tests/testthat/test-test-compiled-code.R
@@ -14,5 +14,13 @@ test_that("validates inputs", {
   })
 })
 
+test_that("useful messaging", {
+  path <- withr::local_tempdir()
+  writeLines("Package: foo", file.path(path, "DESCRIPTION"))
+  dir.create(file.path(path, "R"))
+
+  expect_snapshot(use_catch(path))
+})
+
 skip_if_not_installed("xml2")
 run_cpp_tests("testthat")