From 5bde1e9411612c131fa48e14fce4229b425a1a12 Mon Sep 17 00:00:00 2001
From: VisruthSK <public@visruth.com>
Date: Fri, 3 Apr 2026 14:51:19 -0700
Subject: [PATCH 1/6] Generated snapshot tests

---
 tests/testthat/_snaps/fit-gq.md             | 115 ++++++++++++++++++
 tests/testthat/_snaps/fit-laplace.md        |  23 ++++
 tests/testthat/_snaps/fit-mcmc.md           | 127 ++++++++++++++++++++
 tests/testthat/_snaps/fit-mle.md            |  22 ++++
 tests/testthat/_snaps/fit-vb.md             |  88 ++++++++++++++
 tests/testthat/_snaps/install.md            |  38 ++++++
 tests/testthat/_snaps/print-stan-file.md    | 118 ++++++++++++++++++
 tests/testthat/helper-custom-expectations.R |  28 +++++
 tests/testthat/test-fit-gq.R                |  65 ++++++----
 tests/testthat/test-fit-laplace.R           |  15 ++-
 tests/testthat/test-fit-mcmc.R              |  71 +++++++----
 tests/testthat/test-fit-mle.R               |  15 ++-
 tests/testthat/test-fit-vb.R                |  44 ++++---
 tests/testthat/test-install.R               |  43 ++++---
 tests/testthat/test-print-stan-file.R       |  21 ++--
 15 files changed, 736 insertions(+), 97 deletions(-)
 create mode 100644 tests/testthat/_snaps/fit-gq.md
 create mode 100644 tests/testthat/_snaps/fit-laplace.md
 create mode 100644 tests/testthat/_snaps/fit-mcmc.md
 create mode 100644 tests/testthat/_snaps/fit-mle.md
 create mode 100644 tests/testthat/_snaps/fit-vb.md
 create mode 100644 tests/testthat/_snaps/install.md
 create mode 100644 tests/testthat/_snaps/print-stan-file.md

diff --git a/tests/testthat/_snaps/fit-gq.md b/tests/testthat/_snaps/fit-gq.md
new file mode 100644
index 00000000..fb401fb0
--- /dev/null
+++ b/tests/testthat/_snaps/fit-gq.md
@@ -0,0 +1,115 @@
+# print() method works after gq
+
+    Code
+      full_print <- fit_gq$print()
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      y_rep[2]
+      y_rep[3]
+      y_rep[4]
+      y_rep[5]
+      y_rep[6]
+      y_rep[7]
+      y_rep[8]
+      y_rep[9]
+      y_rep[10]
+      
+      # showing 10 of 11 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_gq$print(max_rows = 1)
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      
+      # showing 1 of 11 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_gq$print(NULL, c("mad"))
+    Output
+      variable mad
+      y_rep[1]
+      y_rep[2]
+      y_rep[3]
+      y_rep[4]
+      y_rep[5]
+      y_rep[6]
+      y_rep[7]
+      y_rep[8]
+      y_rep[9]
+      y_rep[10]
+      
+      # showing 10 of 11 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_gq$print(max_rows = 2)
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      y_rep[2]
+      
+      # showing 2 of 11 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_gq$print(max_rows = 11)
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      y_rep[2]
+      y_rep[3]
+      y_rep[4]
+      y_rep[5]
+      y_rep[6]
+      y_rep[7]
+      y_rep[8]
+      y_rep[9]
+      y_rep[10]
+      sum_y
+
+---
+
+    Code
+      fit_gq$print("y_rep", max_rows = 2)
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      y_rep[2]
+      
+      # showing 2 of 10 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_gq$print("y_rep")
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      y_rep[2]
+      y_rep[3]
+      y_rep[4]
+      y_rep[5]
+      y_rep[6]
+      y_rep[7]
+      y_rep[8]
+      y_rep[9]
+      y_rep[10]
+
+---
+
+    Code
+      fit_gq$print(c("y_rep[1]", "sum_y", "y_rep[3]"))
+    Output
+      variable mean median sd mad q5 q95
+      y_rep[1]
+      sum_y
+      y_rep[3]
+
diff --git a/tests/testthat/_snaps/fit-laplace.md b/tests/testthat/_snaps/fit-laplace.md
new file mode 100644
index 00000000..8ea5f9a7
--- /dev/null
+++ b/tests/testthat/_snaps/fit-laplace.md
@@ -0,0 +1,23 @@
+# summary() and print() methods works after laplace
+
+    Code
+      full_print <- fit_laplace$print()
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      lp_approx__
+      alpha
+      beta[1]
+      beta[2]
+      beta[3]
+
+---
+
+    Code
+      fit_laplace$print(max_rows = 1)
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      
+      # showing 1 of 6 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
diff --git a/tests/testthat/_snaps/fit-mcmc.md b/tests/testthat/_snaps/fit-mcmc.md
new file mode 100644
index 00000000..1905123a
--- /dev/null
+++ b/tests/testthat/_snaps/fit-mcmc.md
@@ -0,0 +1,127 @@
+# print() method works after mcmc
+
+    Code
+      basic_print <- fit_mcmc$print()
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      lp__
+      alpha
+      beta[1]
+      beta[2]
+      beta[3]
+
+---
+
+    Code
+      fit_mcmc$print(max_rows = 1)
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      lp__
+      
+      # showing 1 of 5 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit_mcmc$print(NULL, c("ess_sd"))
+    Output
+      variable ess_sd
+      lp__
+      alpha
+      beta[1]
+      beta[2]
+      beta[3]
+
+---
+
+    Code
+      fit$print()
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      lp__
+      mu
+      tau
+      theta_raw[1]
+      theta_raw[2]
+      theta_raw[3]
+      theta_raw[4]
+      theta_raw[5]
+      theta_raw[6]
+      theta_raw[7]
+      
+      # showing 10 of 19 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit$print(max_rows = 2)
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      lp__
+      mu
+      
+      # showing 2 of 19 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit$print(max_rows = 19)
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      lp__
+      mu
+      tau
+      theta_raw[1]
+      theta_raw[2]
+      theta_raw[3]
+      theta_raw[4]
+      theta_raw[5]
+      theta_raw[6]
+      theta_raw[7]
+      theta_raw[8]
+      theta[1]
+      theta[2]
+      theta[3]
+      theta[4]
+      theta[5]
+      theta[6]
+      theta[7]
+      theta[8]
+
+---
+
+    Code
+      fit$print("theta", max_rows = 2)
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      theta[1]
+      theta[2]
+      
+      # showing 2 of 8 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit$print("theta")
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      theta[1]
+      theta[2]
+      theta[3]
+      theta[4]
+      theta[5]
+      theta[6]
+      theta[7]
+      theta[8]
+
+---
+
+    Code
+      fit$print(c("theta[1]", "tau", "mu", "theta_raw[3]"))
+    Output
+      variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
+      theta[1]
+      tau
+      mu
+      theta_raw[3]
+
diff --git a/tests/testthat/_snaps/fit-mle.md b/tests/testthat/_snaps/fit-mle.md
new file mode 100644
index 00000000..4f2874ba
--- /dev/null
+++ b/tests/testthat/_snaps/fit-mle.md
@@ -0,0 +1,22 @@
+# print() method works after optimization
+
+    Code
+      full_print <- fit_mle$print()
+    Output
+      variable estimate
+      lp__
+      alpha
+      beta[1]
+      beta[2]
+      beta[3]
+
+---
+
+    Code
+      fit_mle$print(max_rows = 1)
+    Output
+      variable estimate
+      lp__
+      
+      # showing 1 of 5 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
diff --git a/tests/testthat/_snaps/fit-vb.md b/tests/testthat/_snaps/fit-vb.md
new file mode 100644
index 00000000..aef0a859
--- /dev/null
+++ b/tests/testthat/_snaps/fit-vb.md
@@ -0,0 +1,88 @@
+# print() method works after vb
+
+    Code
+      basic_print <- fit_vb$print()
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      lp_approx__
+      alpha
+      beta[1]
+      beta[2]
+      beta[3]
+
+---
+
+    Code
+      fit_vb$print(max_rows = 1)
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      
+      # showing 1 of 6 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit$print()
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      lp_approx__
+      mu
+      tau
+      theta_raw[1]
+      theta_raw[2]
+      theta_raw[3]
+      theta_raw[4]
+      theta_raw[5]
+      theta_raw[6]
+      
+      # showing 10 of 20 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
+---
+
+    Code
+      fit$print(max_rows = 20)
+    Output
+      variable mean median sd mad q5 q95
+      lp__
+      lp_approx__
+      mu
+      tau
+      theta_raw[1]
+      theta_raw[2]
+      theta_raw[3]
+      theta_raw[4]
+      theta_raw[5]
+      theta_raw[6]
+      theta_raw[7]
+      theta_raw[8]
+      theta[1]
+      theta[2]
+      theta[3]
+      theta[4]
+      theta[5]
+      theta[6]
+      theta[7]
+      theta[8]
+
+---
+
+    Code
+      fit$print(c("theta", "tau", "lp__", "lp_approx__"))
+    Output
+      variable mean median sd mad q5 q95
+      theta[1]
+      theta[2]
+      theta[3]
+      theta[4]
+      theta[5]
+      theta[6]
+      theta[7]
+      theta[8]
+      tau
+      lp__
+      
+      # showing 10 of 11 rows (change via 'max_rows' argument or 'cmdstanr_max_rows' option)
+
diff --git a/tests/testthat/_snaps/install.md b/tests/testthat/_snaps/install.md
new file mode 100644
index 00000000..46f261c5
--- /dev/null
+++ b/tests/testthat/_snaps/install.md
@@ -0,0 +1,38 @@
+# toolchain checks on Unix work
+
+    Code
+      check_unix_cpp_compiler()
+    Condition
+      Error:
+      ! C++ compiler missing.
+
+---
+
+    Code
+      check_unix_make()
+    Condition
+      Error:
+      ! make missing.
+
+# check_rtools4x_windows_toolchain reports missing Rtools and make
+
+    Code
+      check_rtools4x_windows_toolchain()
+    Condition
+      Error:
+      ! 
+      Rtools<version> was not found but is required to run CmdStan with R version <version>.
+      Please install or reinstall the appropriate Rtools version for this R installation,
+      restart R, and then run cmdstanr::check_cmdstan_toolchain().
+
+---
+
+    Code
+      check_rtools4x_windows_toolchain()
+    Condition
+      Error:
+      ! 
+      Rtools<version> is missing the required 'make' executable in <rtools_usr_bin>.
+      Please reinstall the appropriate Rtools version for this R installation,
+      restart R, and then run cmdstanr::check_cmdstan_toolchain().
+
diff --git a/tests/testthat/_snaps/print-stan-file.md b/tests/testthat/_snaps/print-stan-file.md
new file mode 100644
index 00000000..090c002a
--- /dev/null
+++ b/tests/testthat/_snaps/print-stan-file.md
@@ -0,0 +1,118 @@
+# print_stan_file() prints plain code outside of knitr
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+
+# print_stan_file() outputs fenced code block in knitr with results='asis'
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      ```stan
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+      
+      ```
+
+# print_stan_file() wraps in <details> when fold=TRUE
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      <details><summary>Stan model code</summary>
+      
+      ```stan
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+      
+      ```
+      
+      </details>
+
+# print_stan_file() uses custom summary text
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      <details><summary>My Stan Code</summary>
+      
+      ```stan
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+      
+      ```
+      
+      </details>
+
+# print_stan_file() does not fold when fold=FALSE in knitr
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      ```stan
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+      
+      ```
+
+# print_stan_file() falls back to plain text without results='asis'
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+
+# print_stan_file() falls back to plain text without knitr.in.progress
+
+    Code
+      cat(out, sep = "\n")
+    Output
+      
+      parameters {
+        real y;
+      }
+      model {
+        y ~ std_normal();
+      }
+      
+
diff --git a/tests/testthat/helper-custom-expectations.R b/tests/testthat/helper-custom-expectations.R
index d0128753..58046c71 100644
--- a/tests/testthat/helper-custom-expectations.R
+++ b/tests/testthat/helper-custom-expectations.R
@@ -127,3 +127,31 @@ expect_equal_ignore_order <- function(object, expected, ...) {
 }
 
 expect_not_true <- function(...) expect_false(isTRUE(...))
+
+transform_print_snapshot <- function(x) {
+  vapply(x, function(line) {
+    line <- trimws(line)
+    if (!nzchar(line)) {
+      return(line)
+    }
+    if (grepl("^variable\\b", line)) {
+      return(gsub("\\s+", " ", line))
+    }
+    if (grepl("^# showing", line) ||
+        grepl("^Can't find the following variable\\(s\\):", line)) {
+      return(line)
+    }
+    sub("\\s+.*$", "", line)
+  }, character(1))
+}
+
+transform_unix_toolchain_snapshot <- function(x) {
+  x <- gsub("A suitable C\\+\\+ compiler was not found\\..*", "C++ compiler missing.", x)
+  x <- gsub("A C\\+\\+ compiler was not found\\..*", "C++ compiler missing.", x)
+  gsub("The 'make' tool was not found\\..*", "make missing.", x)
+}
+
+transform_r_version_snapshot <- function(x) {
+  x <- gsub("Rtools[0-9]+", "Rtools<version>", x)
+  gsub("R version [0-9]+\\.[0-9]+\\.[0-9]+", "R version <version>", x)
+}
diff --git a/tests/testthat/test-fit-gq.R b/tests/testthat/test-fit-gq.R
index 4fc43f1f..c29e0a71 100644
--- a/tests/testthat/test-fit-gq.R
+++ b/tests/testthat/test-fit-gq.R
@@ -64,34 +64,55 @@ test_that("summary() method works after gq", {
 })
 
 test_that("print() method works after gq", {
-  expect_output(expect_s3_class(fit_gq$print(), "CmdStanGQ"), "variable")
-  expect_output(fit_gq$print(max_rows = 1), "# showing 1 of 11 rows")
-  expect_output(fit_gq$print(NULL, c("mad")), "mad")
+  full_print <- NULL
+  expect_snapshot(
+    full_print <- fit_gq$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_s3_class(full_print, "CmdStanGQ")
+
+  expect_snapshot(
+    fit_gq$print(max_rows = 1),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print(NULL, c("mad")),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print(max_rows = 2),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print(max_rows = 11),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print("y_rep", max_rows = 2),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print("y_rep"),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_gq$print(c("y_rep[1]", "sum_y", "y_rep[3]")),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
 
-  expect_output(fit_gq$print(), "showing 10 of 11 rows")
-  expect_output(fit_gq$print(max_rows = 2), "showing 2 of 11 rows")
-  expect_output(fit_gq$print(max_rows = 11), "sum_y", fixed=TRUE) # last parameter
-  expect_output(fit_gq$print("y_rep", max_rows = 2), "showing 2 of 10 rows")
   expect_error(
     fit_gq$print(variable = "unknown", max_rows = 20),
     "Can't find the following variable(s): unknown",
     fixed = TRUE
   )
-
-  out <- capture.output(fit_gq$print("y_rep"))
-  expect_length(out, 11) # columns names + 1 y_rep
-  expect_match(out[1], "variable")
-  expect_match(out[2], "y_rep[1]", fixed = TRUE)
-  expect_match(out[9], "y_rep[8]", fixed = TRUE)
-  expect_false(any(grepl("sum_y|theta", out)))
-
-  # make sure the row order is correct
-  out <- capture.output(fit_gq$print(c("y_rep[1]", "sum_y", "y_rep[3]")))
-  expect_length(out, 4)
-  expect_match(out[1], " variable")
-  expect_match(out[2], " y_rep[1]", fixed = TRUE)
-  expect_match(out[3], " sum_y")
-  expect_match(out[4], " y_rep[3]", fixed = TRUE)
 })
 
 test_that("output() method works after gq", {
diff --git a/tests/testthat/test-fit-laplace.R b/tests/testthat/test-fit-laplace.R
index 90415e93..d777c336 100644
--- a/tests/testthat/test-fit-laplace.R
+++ b/tests/testthat/test-fit-laplace.R
@@ -13,8 +13,18 @@ test_that("summary() and print() methods works after laplace", {
   expect_equal(x$variable, c("lp__", "lp_approx__", PARAM_NAMES))
   expect_equal(colnames(x), c("variable", "mean", "sd"))
 
-  expect_output(expect_s3_class(fit_laplace$print(), "CmdStanLaplace"), "variable")
-  expect_output(fit_laplace$print(max_rows = 1), "# showing 1 of 6 rows")
+  full_print <- NULL
+  expect_snapshot(
+    full_print <- fit_laplace$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_s3_class(full_print, "CmdStanLaplace")
+  expect_snapshot(
+    fit_laplace$print(max_rows = 1),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
 })
 
 test_that("draws() method returns posterior sample (reading csv works)", {
@@ -61,4 +71,3 @@ test_that("draws() errors if invalid format", {
     "The supplied draws format is not valid"
   )
 })
-
diff --git a/tests/testthat/test-fit-mcmc.R b/tests/testthat/test-fit-mcmc.R
index aede1110..f1e05b7e 100644
--- a/tests/testthat/test-fit-mcmc.R
+++ b/tests/testthat/test-fit-mcmc.R
@@ -123,37 +123,62 @@ test_that("summary() method works after mcmc", {
 })
 
 test_that("print() method works after mcmc", {
-  expect_output(expect_s3_class(fit_mcmc$print(), "CmdStanMCMC"), "variable")
-  expect_output(fit_mcmc$print(max_rows = 1), "# showing 1 of 5 rows")
-  expect_output(fit_mcmc$print(NULL, c("ess_sd")), "ess_sd")
+  basic_print <- NULL
+  expect_snapshot(
+    basic_print <- fit_mcmc$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_s3_class(basic_print, "CmdStanMCMC")
+  expect_snapshot(
+    fit_mcmc$print(max_rows = 1),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit_mcmc$print(NULL, c("ess_sd")),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
 
   # test on model with more parameters
   fit <- cmdstanr_example("schools_ncp")
-  expect_output(fit$print(), "showing 10 of 19 rows")
-  expect_output(fit$print(max_rows = 2), "showing 2 of 19 rows")
-  expect_output(fit$print(max_rows = 19), "theta[8]", fixed=TRUE) # last parameter
-  expect_output(fit$print("theta", max_rows = 2), "showing 2 of 8 rows")
+  expect_snapshot(
+    fit$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print(max_rows = 2),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print(max_rows = 19),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print("theta", max_rows = 2),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print("theta"),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print(c("theta[1]", "tau", "mu", "theta_raw[3]")),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+
   expect_error(
     fit$print(variable = "unknown", max_rows = 20),
     "Can't find the following variable(s): unknown",
     fixed = TRUE
   )
-
-  out <- capture.output(fit$print("theta"))
-  expect_length(out, 9) # columns names + 8 thetas
-  expect_match(out[1], "variable")
-  expect_match(out[2], "theta[1]", fixed = TRUE)
-  expect_match(out[9], "theta[8]", fixed = TRUE)
-  expect_false(any(grepl("mu|tau|theta_raw", out)))
-
-  # make sure the row order is correct
-  out <- capture.output(fit$print(c("theta[1]", "tau", "mu", "theta_raw[3]")))
-  expect_length(out, 5)
-  expect_match(out[1], " variable")
-  expect_match(out[2], " theta[1]", fixed = TRUE)
-  expect_match(out[3], " tau")
-  expect_match(out[4], " mu")
-  expect_match(out[5], " theta_raw[3]", fixed = TRUE)
 })
 
 test_that("output() method works after mcmc", {
diff --git a/tests/testthat/test-fit-mle.R b/tests/testthat/test-fit-mle.R
index c868a37c..1c709a83 100644
--- a/tests/testthat/test-fit-mle.R
+++ b/tests/testthat/test-fit-mle.R
@@ -22,8 +22,19 @@ test_that("summary method works after optimization", {
 })
 
 test_that("print() method works after optimization", {
-  expect_output(expect_s3_class(fit_mle$print(), "CmdStanMLE"), "estimate")
-  expect_output(fit_mle$print(max_rows = 1), "# showing 1 of 5 rows")
+  full_print <- NULL
+  expect_snapshot(
+    full_print <- fit_mle$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_s3_class(full_print, "CmdStanMLE")
+  expect_snapshot(
+    fit_mle$print(max_rows = 1),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+
   expect_error(
     fit_mle$print(variable = "unknown", max_rows = 20),
     "Can't find the following variable(s): unknown",
diff --git a/tests/testthat/test-fit-vb.R b/tests/testthat/test-fit-vb.R
index f5d2f2c9..1379255c 100644
--- a/tests/testthat/test-fit-vb.R
+++ b/tests/testthat/test-fit-vb.R
@@ -18,29 +18,43 @@ test_that("summary() method works after vb", {
 })
 
 test_that("print() method works after vb", {
-  expect_output(expect_s3_class(fit_vb$print(), "CmdStanVB"), "variable")
-  expect_output(fit_vb$print(max_rows = 1), "# showing 1 of 6 rows")
+  basic_print <- NULL
+  expect_snapshot(
+    basic_print <- fit_vb$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_s3_class(basic_print, "CmdStanVB")
+
+  expect_snapshot(
+    fit_vb$print(max_rows = 1),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
 
   # test on model with more parameters
   fit <- cmdstanr_example("schools_ncp", method = "variational", seed = 123)
-  expect_output(fit$print(), "lp_approx__")
-  expect_output(fit$print(), "showing 10 of 20 rows")
-  expect_output(fit$print(max_rows = 20), "theta[8]", fixed = TRUE) # last parameter
+  expect_snapshot(
+    fit$print(),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print(max_rows = 20),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+  expect_snapshot(
+    fit$print(c("theta", "tau", "lp__", "lp_approx__")),
+    transform = transform_print_snapshot,
+    cran = TRUE
+  )
+
   expect_error(
     fit$print(variable = "unknown", max_rows = 20),
     "Can't find the following variable(s): unknown",
     fixed = TRUE
   ) # unknown parameter
-
-  out <- capture.output(fit$print(c("theta", "tau", "lp__", "lp_approx__")))
-  expect_length(out, 13) # columns names + 8 thetas + tau + lp__ + lp_approx__ + empty + message
-  expect_match(out[1], " variable")
-  expect_match(out[2], " theta[1]", fixed = TRUE)
-  expect_match(out[9], " theta[8]", fixed = TRUE)
-  expect_match(out[10], " tau")
-  expect_match(out[11], " lp__")
-  expect_false(nzchar(out[12])) # empty line
-  expect_match(out[13], "10 of 11 rows")
 })
 
 test_that("draws() method returns posterior sample (reading csv works)", {
diff --git a/tests/testthat/test-install.R b/tests/testthat/test-install.R
index ccb781cc..5968409b 100644
--- a/tests/testthat/test-install.R
+++ b/tests/testthat/test-install.R
@@ -123,22 +123,17 @@ test_that("install_cmdstan() works with version and release_url", {
 test_that("toolchain checks on Unix work", {
   skip_if(os_is_windows())
   withr::local_envvar(c("PATH" = ""))
-  if (os_is_macos()) {
-    err_msg_cpp <- "A suitable C++ compiler was not found. Please install the command line tools for Mac with 'xcode-select --install' or install Xcode from the app store. Then restart R and run cmdstanr::check_cmdstan_toolchain()."
-    err_msg_make <- "The 'make' tool was not found. Please install the command line tools for Mac with 'xcode-select --install' or install Xcode from the app store. Then restart R and run cmdstanr::check_cmdstan_toolchain()."
-  } else {
-    err_msg_cpp <- "A C++ compiler was not found. Please install the 'clang++' or 'g++' compiler, restart R, and run cmdstanr::check_cmdstan_toolchain()."
-    err_msg_make <- "The 'make' tool was not found. Please install 'make', restart R, and then run cmdstanr::check_cmdstan_toolchain()."
-  }
-  expect_error(
+  expect_snapshot(
     check_unix_cpp_compiler(),
-    err_msg_cpp,
-    fixed = TRUE
+    error = TRUE,
+    transform = transform_unix_toolchain_snapshot,
+    cran = TRUE
   )
-  expect_error(
+  expect_snapshot(
     check_unix_make(),
-    err_msg_make,
-    fixed = TRUE
+    error = TRUE,
+    transform = transform_unix_toolchain_snapshot,
+    cran = TRUE
   )
 })
 
@@ -444,10 +439,11 @@ test_that("check_rtools4x_windows_toolchain reports missing Rtools and make", {
       rtools4x_home_path = function() "",
       rtools4x_version = function() "44"
     )
-    expect_error(
+    expect_snapshot(
       check_rtools4x_windows_toolchain(),
-      "restart R, and then run cmdstanr::check_cmdstan_toolchain()",
-      fixed = TRUE
+      error = TRUE,
+      transform = transform_r_version_snapshot,
+      cran = TRUE
     )
   })
 
@@ -458,10 +454,19 @@ test_that("check_rtools4x_windows_toolchain reports missing Rtools and make", {
       rtools4x_home_path = function() fake_rtools_home,
       rtools4x_version = function() "44"
     )
-    expect_error(
+    expect_snapshot(
       check_rtools4x_windows_toolchain(),
-      "restart R, and then run cmdstanr::check_cmdstan_toolchain()",
-      fixed = TRUE
+      error = TRUE,
+      transform = function(x) {
+        x <- transform_r_version_snapshot(x)
+        gsub(
+          repair_path(file.path(fake_rtools_home, "usr", "bin")),
+          "<rtools_usr_bin>",
+          x,
+          fixed = TRUE
+        )
+      },
+      cran = TRUE
     )
   })
 })
diff --git a/tests/testthat/test-print-stan-file.R b/tests/testthat/test-print-stan-file.R
index cc7d6940..cbc1c6d3 100644
--- a/tests/testthat/test-print-stan-file.R
+++ b/tests/testthat/test-print-stan-file.R
@@ -7,11 +7,10 @@ model {
 }
 "
 stan_file <- write_stan_file(stan_code)
-stan_lines <- readLines(stan_file)
 
 test_that("print_stan_file() prints plain code outside of knitr", {
   out <- capture.output(print_stan_file(stan_file))
-  expect_identical(out, stan_lines)
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() returns file path invisibly", {
@@ -21,12 +20,10 @@ test_that("print_stan_file() returns file path invisibly", {
 
 test_that("print_stan_file() outputs fenced code block in knitr with results='asis'", {
   out <- with_mocked_bindings(
-    paste(capture.output(print_stan_file(stan_file)), collapse = "\n"),
+    capture.output(print_stan_file(stan_file)),
     is_knitr_asis_output = function() TRUE
   )
-  expect_match(out, "^```stan\n")
-  expect_match(out, "\n```$")
-  expect_match(out, paste(stan_lines, collapse = "\n"), fixed = TRUE)
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() wraps in <details> when fold=TRUE", {
@@ -34,8 +31,7 @@ test_that("print_stan_file() wraps in <details> when fold=TRUE", {
     capture.output(print_stan_file(stan_file, fold = TRUE)),
     is_knitr_asis_output = function() TRUE
   )
-  expect_match(out[1], "<details><summary>Stan model code</summary>")
-  expect_match(out[length(out)], "</details>")
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() uses custom summary text", {
@@ -43,7 +39,7 @@ test_that("print_stan_file() uses custom summary text", {
     capture.output(print_stan_file(stan_file, fold = TRUE, summary = "My Stan Code")),
     is_knitr_asis_output = function() TRUE
   )
-  expect_match(out[1], "<details><summary>My Stan Code</summary>")
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() does not fold when fold=FALSE in knitr", {
@@ -51,8 +47,7 @@ test_that("print_stan_file() does not fold when fold=FALSE in knitr", {
     capture.output(print_stan_file(stan_file, fold = FALSE)),
     is_knitr_asis_output = function() TRUE
   )
-  expect_no_match(paste(out, collapse = "\n"), "<details>", fixed = TRUE)
-  expect_no_match(paste(out, collapse = "\n"), "</details>", fixed = TRUE)
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() falls back to plain text without results='asis'", {
@@ -60,11 +55,11 @@ test_that("print_stan_file() falls back to plain text without results='asis'", {
     capture.output(print_stan_file(stan_file)),
     is_knitr_asis_output = function() FALSE
   )
-  expect_identical(out, stan_lines)
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })
 
 test_that("print_stan_file() falls back to plain text without knitr.in.progress", {
   withr::local_options(knitr.in.progress = FALSE)
   out <- capture.output(print_stan_file(stan_file))
-  expect_identical(out, stan_lines)
+  expect_snapshot(cat(out, sep = "\n"), cran = TRUE)
 })

From 69d74e7ec2360f8bfdce4dbd270792045e192f6e Mon Sep 17 00:00:00 2001
From: VisruthSK <public@visruth.com>
Date: Fri, 3 Apr 2026 18:53:47 -0700
Subject: [PATCH 2/6] Eerror tests instead of snapshots for install

---
 tests/testthat/_snaps/install.md            | 38 ------------------
 tests/testthat/helper-custom-expectations.R | 11 ------
 tests/testthat/test-install.R               | 43 +++++++++------------
 3 files changed, 19 insertions(+), 73 deletions(-)
 delete mode 100644 tests/testthat/_snaps/install.md

diff --git a/tests/testthat/_snaps/install.md b/tests/testthat/_snaps/install.md
deleted file mode 100644
index 46f261c5..00000000
--- a/tests/testthat/_snaps/install.md
+++ /dev/null
@@ -1,38 +0,0 @@
-# toolchain checks on Unix work
-
-    Code
-      check_unix_cpp_compiler()
-    Condition
-      Error:
-      ! C++ compiler missing.
-
----
-
-    Code
-      check_unix_make()
-    Condition
-      Error:
-      ! make missing.
-
-# check_rtools4x_windows_toolchain reports missing Rtools and make
-
-    Code
-      check_rtools4x_windows_toolchain()
-    Condition
-      Error:
-      ! 
-      Rtools<version> was not found but is required to run CmdStan with R version <version>.
-      Please install or reinstall the appropriate Rtools version for this R installation,
-      restart R, and then run cmdstanr::check_cmdstan_toolchain().
-
----
-
-    Code
-      check_rtools4x_windows_toolchain()
-    Condition
-      Error:
-      ! 
-      Rtools<version> is missing the required 'make' executable in <rtools_usr_bin>.
-      Please reinstall the appropriate Rtools version for this R installation,
-      restart R, and then run cmdstanr::check_cmdstan_toolchain().
-
diff --git a/tests/testthat/helper-custom-expectations.R b/tests/testthat/helper-custom-expectations.R
index 58046c71..74400d77 100644
--- a/tests/testthat/helper-custom-expectations.R
+++ b/tests/testthat/helper-custom-expectations.R
@@ -144,14 +144,3 @@ transform_print_snapshot <- function(x) {
     sub("\\s+.*$", "", line)
   }, character(1))
 }
-
-transform_unix_toolchain_snapshot <- function(x) {
-  x <- gsub("A suitable C\\+\\+ compiler was not found\\..*", "C++ compiler missing.", x)
-  x <- gsub("A C\\+\\+ compiler was not found\\..*", "C++ compiler missing.", x)
-  gsub("The 'make' tool was not found\\..*", "make missing.", x)
-}
-
-transform_r_version_snapshot <- function(x) {
-  x <- gsub("Rtools[0-9]+", "Rtools<version>", x)
-  gsub("R version [0-9]+\\.[0-9]+\\.[0-9]+", "R version <version>", x)
-}
diff --git a/tests/testthat/test-install.R b/tests/testthat/test-install.R
index 5968409b..ccb781cc 100644
--- a/tests/testthat/test-install.R
+++ b/tests/testthat/test-install.R
@@ -123,17 +123,22 @@ test_that("install_cmdstan() works with version and release_url", {
 test_that("toolchain checks on Unix work", {
   skip_if(os_is_windows())
   withr::local_envvar(c("PATH" = ""))
-  expect_snapshot(
+  if (os_is_macos()) {
+    err_msg_cpp <- "A suitable C++ compiler was not found. Please install the command line tools for Mac with 'xcode-select --install' or install Xcode from the app store. Then restart R and run cmdstanr::check_cmdstan_toolchain()."
+    err_msg_make <- "The 'make' tool was not found. Please install the command line tools for Mac with 'xcode-select --install' or install Xcode from the app store. Then restart R and run cmdstanr::check_cmdstan_toolchain()."
+  } else {
+    err_msg_cpp <- "A C++ compiler was not found. Please install the 'clang++' or 'g++' compiler, restart R, and run cmdstanr::check_cmdstan_toolchain()."
+    err_msg_make <- "The 'make' tool was not found. Please install 'make', restart R, and then run cmdstanr::check_cmdstan_toolchain()."
+  }
+  expect_error(
     check_unix_cpp_compiler(),
-    error = TRUE,
-    transform = transform_unix_toolchain_snapshot,
-    cran = TRUE
+    err_msg_cpp,
+    fixed = TRUE
   )
-  expect_snapshot(
+  expect_error(
     check_unix_make(),
-    error = TRUE,
-    transform = transform_unix_toolchain_snapshot,
-    cran = TRUE
+    err_msg_make,
+    fixed = TRUE
   )
 })
 
@@ -439,11 +444,10 @@ test_that("check_rtools4x_windows_toolchain reports missing Rtools and make", {
       rtools4x_home_path = function() "",
       rtools4x_version = function() "44"
     )
-    expect_snapshot(
+    expect_error(
       check_rtools4x_windows_toolchain(),
-      error = TRUE,
-      transform = transform_r_version_snapshot,
-      cran = TRUE
+      "restart R, and then run cmdstanr::check_cmdstan_toolchain()",
+      fixed = TRUE
     )
   })
 
@@ -454,19 +458,10 @@ test_that("check_rtools4x_windows_toolchain reports missing Rtools and make", {
       rtools4x_home_path = function() fake_rtools_home,
       rtools4x_version = function() "44"
     )
-    expect_snapshot(
+    expect_error(
       check_rtools4x_windows_toolchain(),
-      error = TRUE,
-      transform = function(x) {
-        x <- transform_r_version_snapshot(x)
-        gsub(
-          repair_path(file.path(fake_rtools_home, "usr", "bin")),
-          "<rtools_usr_bin>",
-          x,
-          fixed = TRUE
-        )
-      },
-      cran = TRUE
+      "restart R, and then run cmdstanr::check_cmdstan_toolchain()",
+      fixed = TRUE
     )
   })
 })

From cdbea48fa86d9bd21354a2c6fde6653391992f88 Mon Sep 17 00:00:00 2001
From: VisruthSK <public@visruth.com>
Date: Mon, 6 Apr 2026 08:25:08 -0700
Subject: [PATCH 3/6] Cleaned up code slightly

---
 tests/testthat/_snaps/fit-gq.md                 |  2 +-
 tests/testthat/_snaps/fit-laplace.md            |  2 +-
 tests/testthat/_snaps/fit-mcmc.md               |  2 +-
 tests/testthat/_snaps/fit-mle.md                |  2 +-
 tests/testthat/_snaps/fit-vb.md                 |  2 +-
 tests/testthat/test-fit-gq.R                    |  4 +---
 tests/testthat/test-fit-laplace.R               |  4 +---
 tests/testthat/test-fit-mcmc.R                  |  4 +---
 tests/testthat/test-fit-mle.R                   |  4 +---
 tests/testthat/test-fit-vb.R                    |  4 +---
 tests/testthat/test-model-compile-user_header.R |  5 ++---
 tests/testthat/test-model-recompile-logic.R     | 10 +++-------
 12 files changed, 15 insertions(+), 30 deletions(-)

diff --git a/tests/testthat/_snaps/fit-gq.md b/tests/testthat/_snaps/fit-gq.md
index fb401fb0..77e09252 100644
--- a/tests/testthat/_snaps/fit-gq.md
+++ b/tests/testthat/_snaps/fit-gq.md
@@ -1,7 +1,7 @@
 # print() method works after gq
 
     Code
-      full_print <- fit_gq$print()
+      expect_s3_class(fit_gq$print(), "CmdStanGQ")
     Output
       variable mean median sd mad q5 q95
       y_rep[1]
diff --git a/tests/testthat/_snaps/fit-laplace.md b/tests/testthat/_snaps/fit-laplace.md
index 8ea5f9a7..4effe964 100644
--- a/tests/testthat/_snaps/fit-laplace.md
+++ b/tests/testthat/_snaps/fit-laplace.md
@@ -1,7 +1,7 @@
 # summary() and print() methods works after laplace
 
     Code
-      full_print <- fit_laplace$print()
+      expect_s3_class(fit_laplace$print(), "CmdStanLaplace")
     Output
       variable mean median sd mad q5 q95
       lp__
diff --git a/tests/testthat/_snaps/fit-mcmc.md b/tests/testthat/_snaps/fit-mcmc.md
index 1905123a..004cc382 100644
--- a/tests/testthat/_snaps/fit-mcmc.md
+++ b/tests/testthat/_snaps/fit-mcmc.md
@@ -1,7 +1,7 @@
 # print() method works after mcmc
 
     Code
-      basic_print <- fit_mcmc$print()
+      expect_s3_class(fit_mcmc$print(), "CmdStanMCMC")
     Output
       variable mean median sd mad q5 q95 rhat ess_bulk ess_tail
       lp__
diff --git a/tests/testthat/_snaps/fit-mle.md b/tests/testthat/_snaps/fit-mle.md
index 4f2874ba..2e5b14e6 100644
--- a/tests/testthat/_snaps/fit-mle.md
+++ b/tests/testthat/_snaps/fit-mle.md
@@ -1,7 +1,7 @@
 # print() method works after optimization
 
     Code
-      full_print <- fit_mle$print()
+      expect_s3_class(fit_mle$print(), "CmdStanMLE")
     Output
       variable estimate
       lp__
diff --git a/tests/testthat/_snaps/fit-vb.md b/tests/testthat/_snaps/fit-vb.md
index aef0a859..cfd3a703 100644
--- a/tests/testthat/_snaps/fit-vb.md
+++ b/tests/testthat/_snaps/fit-vb.md
@@ -1,7 +1,7 @@
 # print() method works after vb
 
     Code
-      basic_print <- fit_vb$print()
+      expect_s3_class(fit_vb$print(), "CmdStanVB")
     Output
       variable mean median sd mad q5 q95
       lp__
diff --git a/tests/testthat/test-fit-gq.R b/tests/testthat/test-fit-gq.R
index c29e0a71..972eea1f 100644
--- a/tests/testthat/test-fit-gq.R
+++ b/tests/testthat/test-fit-gq.R
@@ -64,13 +64,11 @@ test_that("summary() method works after gq", {
 })
 
 test_that("print() method works after gq", {
-  full_print <- NULL
   expect_snapshot(
-    full_print <- fit_gq$print(),
+    expect_s3_class(fit_gq$print(), "CmdStanGQ"),
     transform = transform_print_snapshot,
     cran = TRUE
   )
-  expect_s3_class(full_print, "CmdStanGQ")
 
   expect_snapshot(
     fit_gq$print(max_rows = 1),
diff --git a/tests/testthat/test-fit-laplace.R b/tests/testthat/test-fit-laplace.R
index d777c336..d598a8c4 100644
--- a/tests/testthat/test-fit-laplace.R
+++ b/tests/testthat/test-fit-laplace.R
@@ -13,13 +13,11 @@ test_that("summary() and print() methods works after laplace", {
   expect_equal(x$variable, c("lp__", "lp_approx__", PARAM_NAMES))
   expect_equal(colnames(x), c("variable", "mean", "sd"))
 
-  full_print <- NULL
   expect_snapshot(
-    full_print <- fit_laplace$print(),
+    expect_s3_class(fit_laplace$print(), "CmdStanLaplace"),
     transform = transform_print_snapshot,
     cran = TRUE
   )
-  expect_s3_class(full_print, "CmdStanLaplace")
   expect_snapshot(
     fit_laplace$print(max_rows = 1),
     transform = transform_print_snapshot,
diff --git a/tests/testthat/test-fit-mcmc.R b/tests/testthat/test-fit-mcmc.R
index f1e05b7e..29338a80 100644
--- a/tests/testthat/test-fit-mcmc.R
+++ b/tests/testthat/test-fit-mcmc.R
@@ -123,13 +123,11 @@ test_that("summary() method works after mcmc", {
 })
 
 test_that("print() method works after mcmc", {
-  basic_print <- NULL
   expect_snapshot(
-    basic_print <- fit_mcmc$print(),
+    expect_s3_class(fit_mcmc$print(), "CmdStanMCMC"),
     transform = transform_print_snapshot,
     cran = TRUE
   )
-  expect_s3_class(basic_print, "CmdStanMCMC")
   expect_snapshot(
     fit_mcmc$print(max_rows = 1),
     transform = transform_print_snapshot,
diff --git a/tests/testthat/test-fit-mle.R b/tests/testthat/test-fit-mle.R
index 1c709a83..bad5df7a 100644
--- a/tests/testthat/test-fit-mle.R
+++ b/tests/testthat/test-fit-mle.R
@@ -22,13 +22,11 @@ test_that("summary method works after optimization", {
 })
 
 test_that("print() method works after optimization", {
-  full_print <- NULL
   expect_snapshot(
-    full_print <- fit_mle$print(),
+    expect_s3_class(fit_mle$print(), "CmdStanMLE"),
     transform = transform_print_snapshot,
     cran = TRUE
   )
-  expect_s3_class(full_print, "CmdStanMLE")
   expect_snapshot(
     fit_mle$print(max_rows = 1),
     transform = transform_print_snapshot,
diff --git a/tests/testthat/test-fit-vb.R b/tests/testthat/test-fit-vb.R
index 1379255c..52ee652b 100644
--- a/tests/testthat/test-fit-vb.R
+++ b/tests/testthat/test-fit-vb.R
@@ -18,13 +18,11 @@ test_that("summary() method works after vb", {
 })
 
 test_that("print() method works after vb", {
-  basic_print <- NULL
   expect_snapshot(
-    basic_print <- fit_vb$print(),
+    expect_s3_class(fit_vb$print(), "CmdStanVB"),
     transform = transform_print_snapshot,
     cran = TRUE
   )
-  expect_s3_class(basic_print, "CmdStanVB")
 
   expect_snapshot(
     fit_vb$print(max_rows = 1),
diff --git a/tests/testthat/test-model-compile-user_header.R b/tests/testthat/test-model-compile-user_header.R
index 8f549953..1d5f7546 100644
--- a/tests/testthat/test-model-compile-user_header.R
+++ b/tests/testthat/test-model-compile-user_header.R
@@ -1,8 +1,7 @@
 skip_if(os_is_macos())
 
-file_that_exists <- "placeholder_exists"
-file_that_doesnt_exist <- "placeholder_doesnt_exist"
-withr::local_file(file_that_exists)
+file_that_exists <- withr::local_tempfile(pattern = "placeholder_exists")
+file_that_doesnt_exist <- withr::local_tempfile(pattern = "placeholder_doesnt_exist")
 
 w_path <- function(f) {
   x <- sapply(f, function(fi) wsl_safe_path(absolute_path(fi)))
diff --git a/tests/testthat/test-model-recompile-logic.R b/tests/testthat/test-model-recompile-logic.R
index caac4f13..c9d7a385 100644
--- a/tests/testthat/test-model-recompile-logic.R
+++ b/tests/testthat/test-model-recompile-logic.R
@@ -1,11 +1,7 @@
 stan_program <- cmdstan_example_file()
-file_that_doesnt_exist <- "placeholder_doesnt_exist"
-file_that_exists <- "placeholder_exists"
+file_that_doesnt_exist <- withr::local_tempfile(pattern = "placeholder_doesnt_exist")
+file_that_exists <- withr::local_tempfile(pattern = "placeholder_exists")
 file.create(file_that_exists)
-withr::defer(
-  if (file.exists(file_that_exists)) file.remove(file_that_exists),
-  teardown_env()
-)
 
 skip_message <- "To be fixed in a later version."
 
@@ -106,4 +102,4 @@ test_that("recompile when cpp args don't match binary", {
       )
     })
   )
-})
\ No newline at end of file
+})

From f37f5fbcca777a2d144865d95d987b3a4bda16bc Mon Sep 17 00:00:00 2001
From: VisruthSK <public@visruth.com>
Date: Tue, 7 Apr 2026 18:19:41 -0700
Subject: [PATCH 4/6] Don't run some snapshots on CRAN

---
 tests/testthat/test-fit-gq.R           | 16 ++++++++--------
 tests/testthat/test-fit-laplace.R      |  4 ++--
 tests/testthat/test-fit-mcmc.R         | 18 +++++++++---------
 tests/testthat/test-fit-mle.R          |  4 ++--
 tests/testthat/test-fit-vb.R           | 10 +++++-----
 tests/testthat/test-model-code-print.R |  4 ++--
 6 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/tests/testthat/test-fit-gq.R b/tests/testthat/test-fit-gq.R
index 972eea1f..bf7cfa33 100644
--- a/tests/testthat/test-fit-gq.R
+++ b/tests/testthat/test-fit-gq.R
@@ -67,43 +67,43 @@ test_that("print() method works after gq", {
   expect_snapshot(
     expect_s3_class(fit_gq$print(), "CmdStanGQ"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_snapshot(
     fit_gq$print(max_rows = 1),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print(NULL, c("mad")),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print(max_rows = 2),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print(max_rows = 11),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print("y_rep", max_rows = 2),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print("y_rep"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_gq$print(c("y_rep[1]", "sum_y", "y_rep[3]")),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_error(
diff --git a/tests/testthat/test-fit-laplace.R b/tests/testthat/test-fit-laplace.R
index d598a8c4..54933eef 100644
--- a/tests/testthat/test-fit-laplace.R
+++ b/tests/testthat/test-fit-laplace.R
@@ -16,12 +16,12 @@ test_that("summary() and print() methods works after laplace", {
   expect_snapshot(
     expect_s3_class(fit_laplace$print(), "CmdStanLaplace"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_laplace$print(max_rows = 1),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 })
 
diff --git a/tests/testthat/test-fit-mcmc.R b/tests/testthat/test-fit-mcmc.R
index 29338a80..09507ba8 100644
--- a/tests/testthat/test-fit-mcmc.R
+++ b/tests/testthat/test-fit-mcmc.R
@@ -126,17 +126,17 @@ test_that("print() method works after mcmc", {
   expect_snapshot(
     expect_s3_class(fit_mcmc$print(), "CmdStanMCMC"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_mcmc$print(max_rows = 1),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_mcmc$print(NULL, c("ess_sd")),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   # test on model with more parameters
@@ -144,32 +144,32 @@ test_that("print() method works after mcmc", {
   expect_snapshot(
     fit$print(),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print(max_rows = 2),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print(max_rows = 19),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print("theta", max_rows = 2),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print("theta"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print(c("theta[1]", "tau", "mu", "theta_raw[3]")),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_error(
diff --git a/tests/testthat/test-fit-mle.R b/tests/testthat/test-fit-mle.R
index bad5df7a..e65b9205 100644
--- a/tests/testthat/test-fit-mle.R
+++ b/tests/testthat/test-fit-mle.R
@@ -25,12 +25,12 @@ test_that("print() method works after optimization", {
   expect_snapshot(
     expect_s3_class(fit_mle$print(), "CmdStanMLE"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit_mle$print(max_rows = 1),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_error(
diff --git a/tests/testthat/test-fit-vb.R b/tests/testthat/test-fit-vb.R
index 52ee652b..bac2d079 100644
--- a/tests/testthat/test-fit-vb.R
+++ b/tests/testthat/test-fit-vb.R
@@ -21,13 +21,13 @@ test_that("print() method works after vb", {
   expect_snapshot(
     expect_s3_class(fit_vb$print(), "CmdStanVB"),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_snapshot(
     fit_vb$print(max_rows = 1),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   # test on model with more parameters
@@ -35,17 +35,17 @@ test_that("print() method works after vb", {
   expect_snapshot(
     fit$print(),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print(max_rows = 20),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
   expect_snapshot(
     fit$print(c("theta", "tau", "lp__", "lp_approx__")),
     transform = transform_print_snapshot,
-    cran = TRUE
+    cran = FALSE
   )
 
   expect_error(
diff --git a/tests/testthat/test-model-code-print.R b/tests/testthat/test-model-code-print.R
index 16fdaa81..81621893 100644
--- a/tests/testthat/test-model-code-print.R
+++ b/tests/testthat/test-model-code-print.R
@@ -3,8 +3,8 @@ stan_program <- testing_stan_file("bernoulli")
 mod <- testing_model("bernoulli")
 
 test_that("code() and print() methods work", {
-  expect_snapshot_output(mod$print(), cran = TRUE)
-  expect_snapshot_value(mod$code(), style = "deparse", cran = TRUE)
+  expect_snapshot_output(mod$print(), cran = FALSE)
+  expect_snapshot_value(mod$code(), style = "deparse", cran = FALSE)
 })
 
 test_that("code() and print() still work if file is removed", {

From 7cc635b8336afac3d6da5032d3fe6718c4db2f59 Mon Sep 17 00:00:00 2001
From: Visruth Srimath Kandali <public@visruth.com>
Date: Wed, 8 Apr 2026 22:59:59 -0700
Subject: [PATCH 5/6] Update tests/testthat/helper-custom-expectations.R

Co-authored-by: Jonah Gabry <jgabry@gmail.com>
---
 tests/testthat/helper-custom-expectations.R | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/testthat/helper-custom-expectations.R b/tests/testthat/helper-custom-expectations.R
index 74400d77..5223581b 100644
--- a/tests/testthat/helper-custom-expectations.R
+++ b/tests/testthat/helper-custom-expectations.R
@@ -128,6 +128,8 @@ expect_equal_ignore_order <- function(object, expected, ...) {
 
 expect_not_true <- function(...) expect_false(isTRUE(...))
 
+# strips numeric values (which may change slightly with different hardware or compilers) 
+# allowing us to still verify names, ordering, column headers, row counts, etc.
 transform_print_snapshot <- function(x) {
   vapply(x, function(line) {
     line <- trimws(line)

From 6201b5638a348a520f097c11df10f74a233d5b34 Mon Sep 17 00:00:00 2001
From: VisruthSK <public@visruth.com>
Date: Wed, 8 Apr 2026 23:17:06 -0700
Subject: [PATCH 6/6] Actually create existing file

---
 tests/testthat/test-model-compile-user_header.R | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/testthat/test-model-compile-user_header.R b/tests/testthat/test-model-compile-user_header.R
index 1d5f7546..1002b866 100644
--- a/tests/testthat/test-model-compile-user_header.R
+++ b/tests/testthat/test-model-compile-user_header.R
@@ -1,6 +1,7 @@
 skip_if(os_is_macos())
 
 file_that_exists <- withr::local_tempfile(pattern = "placeholder_exists")
+file.create(file_that_exists)
 file_that_doesnt_exist <- withr::local_tempfile(pattern = "placeholder_doesnt_exist")
 
 w_path <- function(f) {