diff --git a/doc/languages-frameworks/rust.section.md b/doc/languages-frameworks/rust.section.md
index 7f9d93216ed..0e1d59e1a95 100644
--- a/doc/languages-frameworks/rust.section.md
+++ b/doc/languages-frameworks/rust.section.md
@@ -119,6 +119,18 @@ The above are just guidelines, and exceptions may be granted on a case-by-case b
 However, please check if it's possible to disable a problematic subset of the
 test suite and leave a comment explaining your reasoning.
 
+#### Setting `test-threads`
+
+`buildRustPackage` will use parallel test threads by default,
+sometimes it may be necessary to disable this so the tests run consecutively.
+
+```nix
+rustPlatform.buildRustPackage {
+  /* ... */
+  cargoParallelTestThreads = false;
+}
+```
+
 ### Building a package in `debug` mode
 
 By default, `buildRustPackage` will use `release` mode for builds. If a package
diff --git a/pkgs/applications/networking/browsers/castor/default.nix b/pkgs/applications/networking/browsers/castor/default.nix
index dd8ddd2dccb..c9ad213cf1d 100644
--- a/pkgs/applications/networking/browsers/castor/default.nix
+++ b/pkgs/applications/networking/browsers/castor/default.nix
@@ -39,8 +39,7 @@ rustPlatform.buildRustPackage rec {
   postInstall = "make PREFIX=$out copy-data";
 
   # Sometimes tests fail when run in parallel
-  #checkFlags = [ "--test-threads=1" ];
-  doCheck = false;
+  cargoParallelTestThreads = false;
 
   meta = with stdenv.lib; {
     description = "A graphical client for plain-text protocols written in Rust with GTK. It currently supports the Gemini, Gopher and Finger protocols";
@@ -49,4 +48,3 @@ rustPlatform.buildRustPackage rec {
     maintainers = with maintainers; [ fgaz ];
   };
 }
-
diff --git a/pkgs/applications/version-management/git-and-tools/git-interactive-rebase-tool/default.nix b/pkgs/applications/version-management/git-and-tools/git-interactive-rebase-tool/default.nix
index e6185ec8ab9..b656deaa716 100644
--- a/pkgs/applications/version-management/git-and-tools/git-interactive-rebase-tool/default.nix
+++ b/pkgs/applications/version-management/git-and-tools/git-interactive-rebase-tool/default.nix
@@ -15,8 +15,7 @@ rustPlatform.buildRustPackage rec {
 
   buildInputs = [ ncurses5 ] ++ stdenv.lib.optionals stdenv.isDarwin [ libiconv Security ];
 
-  #checkFlagsArray = [ "--test-threads=1" ];
-  doCheck = false;
+  cargoParallelTestThreads = false;
 
   meta = with stdenv.lib; {
     homepage = "https://github.com/MitMaro/git-interactive-rebase-tool";
diff --git a/pkgs/build-support/rust/default.nix b/pkgs/build-support/rust/default.nix
index 0103e064828..f6177ce198d 100644
--- a/pkgs/build-support/rust/default.nix
+++ b/pkgs/build-support/rust/default.nix
@@ -30,6 +30,8 @@
 , cargoVendorDir ? null
 , checkType ? buildType
 , depsExtraArgs ? {}
+, cargoParallelTestThreads ? true
+
 # Needed to `pushd`/`popd` into a subdir of a tarball if this subdir
 # contains a Cargo.toml, but isn't part of a workspace (which is e.g. the
 # case for `rustfmt`/etc from the `rust-sources).
@@ -204,11 +206,12 @@ stdenv.mkDerivation ((removeAttrs args ["depsExtraArgs"]) // {
 
   checkPhase = args.checkPhase or (let
     argstr = "${stdenv.lib.optionalString (checkType == "release") "--release"} --target ${rustTarget} --frozen";
+    threads = if cargoParallelTestThreads then "$NIX_BUILD_CORES" else "1";
   in ''
     ${stdenv.lib.optionalString (buildAndTestSubdir != null) "pushd ${buildAndTestSubdir}"}
     runHook preCheck
     echo "Running cargo test ${argstr} -- ''${checkFlags} ''${checkFlagsArray+''${checkFlagsArray[@]}}"
-    cargo test -j $NIX_BUILD_CORES ${argstr} -- --test-threads=$NIX_BUILD_CORES ''${checkFlags} ''${checkFlagsArray+"''${checkFlagsArray[@]}"}
+    cargo test -j $NIX_BUILD_CORES ${argstr} -- --test-threads=${threads} ''${checkFlags} ''${checkFlagsArray+"''${checkFlagsArray[@]}"}
     runHook postCheck
     ${stdenv.lib.optionalString (buildAndTestSubdir != null) "popd"}
   '');
diff --git a/pkgs/development/tools/the-way/default.nix b/pkgs/development/tools/the-way/default.nix
index dce18580577..6042f5f891a 100644
--- a/pkgs/development/tools/the-way/default.nix
+++ b/pkgs/development/tools/the-way/default.nix
@@ -16,8 +16,8 @@ rustPlatform.buildRustPackage rec {
   buildInputs = stdenv.lib.optionals stdenv.isDarwin  [ AppKit Security ];
 
   cargoSha256 = "0adhgp6blwx7s1hlwqzzsgkzc43q9avxx8a9ykvvv2s1w7m9ql78";
-  #checkFlags = "--test-threads=1";
-  doCheck = false;
+  checkFlagsArray = stdenv.lib.optionals stdenv.isDarwin [ "--skip=copy" ];
+  cargoParallelTestThreads = false;
 
   postInstall = ''
     $out/bin/the-way config default tmp.toml