Use serial_test when using HOST_OPTIONS.scoped_options

Add a suggestion to the docs to use this. It can help prevent tests from
conflicting with each other if they modify HOST_OPTIONS.

Author: jrray

Cargo.lock

@@ -30,6 +30,7 @@ spk-cmd-make-source = { workspace = true }
 
 [dev-dependencies]
 rstest = { workspace = true }
+serial_test = { workspace = true }
 spk-schema = { workspace = true }
 spk-storage = { workspace = true }
 tempfile = { workspace = true }

crates/spk-cli/cmd-build/Cargo.toml

@@ -611,6 +611,7 @@ build:
 // this case passes because host options override default values, and the
 // provided host option value of "linux" is a valid choice.
 #[case::non_empty_value_for_host_option_bad_value_succeeds_with_host_options_enabled("os", "beos", &["linux", "windows"], true)]
+#[serial_test::serial(host_options)]
 #[tokio::test]
 async fn test_options_with_choices_and_empty_values(
     tmpdir: tempfile::TempDir,

crates/spk-cli/cmd-build/src/cmd_build_test/mod.rs

@@ -661,6 +661,7 @@ build:
 }
 
 #[rstest]
+#[serial_test::serial(host_options)]
 #[tokio::test]
 async fn test_build_filters_variants_based_on_host_opts(tmpdir: tempfile::TempDir) {
     let _rt = spfs_runtime().await;

crates/spk-cli/cmd-build/src/cmd_build_test/variant_filter.rs

@@ -42,6 +42,7 @@ ring = { workspace = true }
 rstest = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_yaml = { workspace = true }
+serial_test = { workspace = true }
 spfs = { workspace = true }
 strum = { workspace = true, features = ["derive"] }
 sys-info = "0.9.0"

crates/spk-schema/crates/foundation/Cargo.toml

@@ -101,10 +101,12 @@ impl HostOptions {
     /// Change [`HOST_OPTIONS`] to return the provided substitute options for
     /// the duration of the given future.
     ///
-    /// There is no guarantee that some other concurrent task doesn't also
-    /// change the options before the given future completes.
-    ///
     /// This method is intended to only be used by tests.
+    ///
+    /// There is no guarantee that some other concurrent task doesn't also
+    /// change the options before the given future completes. It is recommended
+    /// to use [`serial_test::serial`] and include the key "host_options" when
+    /// using this function.
     pub async fn scoped_options<T>(
         &self,
         substitute_host_options: Result<OptionMap>,