Disable libparsec_client's async stateful tests on web

Async stateful tests manages their own Tokio runtime, which is not
possible on web where Tokio runtime is not supported.

libparsec/crates/client/Cargo.toml

@@ -31,5 +31,10 @@ proptest-state-machine = { workspace = true }
 libparsec_platform_storage = { workspace = true, features = ["expose-test-methods"] }
 libparsec_client = { workspace = true, features = ["expose-test-methods"] }
 
+# Async stateful test currently relies on Tokio runtime, which is not available on web.
+# This is no big deal though, since the tested code is supposed to be platform agnostic.
+[target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+tokio = { workspace = true, features = ["rt"] }
+
 [features]
 expose-test-methods = []

libparsec/crates/client/tests/unit/workspace/mod.rs

@@ -35,10 +35,11 @@ mod store;
 mod utils;
 mod watch_entry;
 
-#[cfg(unix)]
+#[cfg(unix)] // Test uses UNIX filesystem as oracle
+#[cfg(not(target_arch = "wasm32"))] // Async stateful requires Tokio runtime
 mod file_transactions_stateful;
 
-#[cfg(unix)]
+#[allow(dead_code)]
 pub trait AsyncStateMachineTest {
     /// The concrete state, that is the system under test (SUT).
     type SystemUnderTest;
@@ -90,6 +91,7 @@ pub trait AsyncStateMachineTest {
     }
 }
 
+#[allow(dead_code)]
 #[macro_export]
 macro_rules! impl_async_state_machine {
     ($t:ty) => {