diff --git a/R/find_rev.R b/R/find_rev.R
index 8a06e1ca..eaf01377 100644
--- a/R/find_rev.R
+++ b/R/find_rev.R
@@ -494,7 +494,7 @@ tex_pkgs)
   # to add it.
   generate_system_pkgs <- function(system_pkgs, r_pkgs){
     sprintf('system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales %s;
+  inherit (pkgs) R glibcLocales nix %s;
 };
 ',
 get_system_pkgs(system_pkgs, r_pkgs))
diff --git a/dev/flat_build_envs.Rmd b/dev/flat_build_envs.Rmd
index d2a71e21..7139eef8 100644
--- a/dev/flat_build_envs.Rmd
+++ b/dev/flat_build_envs.Rmd
@@ -617,7 +617,7 @@ tex_pkgs)
   # to add it.
   generate_system_pkgs <- function(system_pkgs, r_pkgs){
     sprintf('system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales %s;
+  inherit (pkgs) R glibcLocales nix %s;
 };
 ',
 get_system_pkgs(system_pkgs, r_pkgs))
@@ -1296,7 +1296,7 @@ nix_rprofile <- function() {
 ```{r, tests-rix_init}
 testthat::test_that("Snapshot test of rix_init()", {
 
-  skip_on_covr()
+  #skip_on_covr()
 
   save_rix_init_test <- function() {
 
@@ -2159,9 +2159,7 @@ testthat::test_that("Testing with_nix() if Nix is installed", {
 
   #skip_on_covr()
 
-  path_subshell <- file.path(".", "_env_R_3_5_3")
-
-  on.exit(unlink(path_subshell, recursive = TRUE, force = TRUE))
+  path_subshell <- tempdir()
 
   rix_init(
     project_path = path_subshell,
diff --git a/tests/testthat/_snaps/find_rev/code_default.nix b/tests/testthat/_snaps/find_rev/code_default.nix
index e80c76de..65111b74 100644
--- a/tests/testthat/_snaps/find_rev/code_default.nix
+++ b/tests/testthat/_snaps/find_rev/code_default.nix
@@ -41,7 +41,7 @@ let
   inherit (pkgs.texlive) scheme-small amsmath;
 });
  system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales quarto;
+  inherit (pkgs) R glibcLocales nix quarto;
 };
   in
   pkgs.mkShell {
diff --git a/tests/testthat/_snaps/find_rev/no_quarto_default.nix b/tests/testthat/_snaps/find_rev/no_quarto_default.nix
index 3e1552fb..1ba16870 100644
--- a/tests/testthat/_snaps/find_rev/no_quarto_default.nix
+++ b/tests/testthat/_snaps/find_rev/no_quarto_default.nix
@@ -5,7 +5,7 @@ let
   inherit (pkgs.rPackages) dplyr;
 };
    system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales ;
+  inherit (pkgs) R glibcLocales nix ;
 };
   in
   pkgs.mkShell {
diff --git a/tests/testthat/_snaps/find_rev/other_default.nix b/tests/testthat/_snaps/find_rev/other_default.nix
index 478e7f5c..e2154ee5 100644
--- a/tests/testthat/_snaps/find_rev/other_default.nix
+++ b/tests/testthat/_snaps/find_rev/other_default.nix
@@ -41,7 +41,7 @@ let
   inherit (pkgs.texlive) scheme-small amsmath;
 });
  system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales quarto;
+  inherit (pkgs) R glibcLocales nix quarto;
 };
   in
   pkgs.mkShell {
diff --git a/tests/testthat/_snaps/find_rev/rstudio_default.nix b/tests/testthat/_snaps/find_rev/rstudio_default.nix
index 11d7a278..167ad560 100644
--- a/tests/testthat/_snaps/find_rev/rstudio_default.nix
+++ b/tests/testthat/_snaps/find_rev/rstudio_default.nix
@@ -41,7 +41,7 @@ let
   inherit (pkgs.texlive) scheme-small amsmath;
 });
  system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales quarto;
+  inherit (pkgs) R glibcLocales nix quarto;
 };
  rstudio_pkgs = pkgs.rstudioWrapper.override {
   packages = [ git_archive_pkgs rpkgs ];
diff --git a/tests/testthat/_snaps/find_rev/yes_quarto_default.nix b/tests/testthat/_snaps/find_rev/yes_quarto_default.nix
index 17acbd36..1e4ffafa 100644
--- a/tests/testthat/_snaps/find_rev/yes_quarto_default.nix
+++ b/tests/testthat/_snaps/find_rev/yes_quarto_default.nix
@@ -5,7 +5,7 @@ let
   inherit (pkgs.rPackages) dplyr quarto;
 };
    system_packages = builtins.attrValues {
-  inherit (pkgs) R glibcLocales quarto;
+  inherit (pkgs) R glibcLocales nix quarto;
 };
   in
   pkgs.mkShell {
diff --git a/tests/testthat/test-find_rev.R b/tests/testthat/test-find_rev.R
index 9a16ebf1..7e7207b7 100644
--- a/tests/testthat/test-find_rev.R
+++ b/tests/testthat/test-find_rev.R
@@ -142,7 +142,7 @@ testthat::test_that("Quarto gets added to sys packages", {
 
 testthat::test_that("Snapshot test of rix_init()", {
 
-  skip_on_covr()
+  #skip_on_covr()
 
   save_rix_init_test <- function() {
 
@@ -172,9 +172,7 @@ testthat::test_that("Testing with_nix() if Nix is installed", {
 
   #skip_on_covr()
 
-  path_subshell <- file.path(".", "_env_R_3_5_3")
-
-  on.exit(unlink(path_subshell, recursive = TRUE, force = TRUE))
+  path_subshell <- tempdir()
 
   rix_init(
     project_path = path_subshell,