tor-circmgr: Provide testing feature and TestConfig

Like the similar thing in tor-guardmgr.

Cargo.lock

@@ -3731,6 +3731,7 @@ dependencies = [
  "async-trait",
  "bounded-vec-deque",
  "derive_builder_fork_arti",
+ "derive_more",
  "downcast-rs",
  "dyn-clone",
  "educe",

crates/tor-circmgr/Cargo.toml

@@ -17,6 +17,10 @@ default = []
 full = ["specific-relay"]
 specific-relay = []
 
+# Enable testing-only APIs.  APIs under this feature are not
+# covered by semver.
+testing = []
+
 # Enable experimental APIs that are not yet officially supported.
 #
 # These APIs are not covered by semantic versioning.  Using this
@@ -31,6 +35,7 @@ hs-common = ["tor-hscrypto"]
 async-trait = "0.1.2"
 bounded-vec-deque = "0.1"
 derive_builder = { version = "0.11.2", package = "derive_builder_fork_arti" }
+derive_more = "0.99.3"
 downcast-rs = "1.2.0"
 dyn-clone = "1.0.4"
 educe = "0.4.6"

crates/tor-circmgr/src/config.rs

@@ -292,6 +292,49 @@ define_accessor_trait! {
     }
 }
 
+/// Testing configuration, with public fields
+#[cfg(feature = "testing")]
+pub(crate) mod test_config {
+    use super::*;
+    use crate::*;
+    use tor_guardmgr::bridge::BridgeConfig;
+
+    /// Testing configuration, with public fields
+    #[derive(Default)]
+    #[derive(derive_more::AsRef)]
+    #[allow(clippy::exhaustive_structs)]
+    pub struct TestConfig {
+        ///
+        pub path_rules: PathConfig,
+        ///
+        pub circuit_timing: CircuitTiming,
+        ///
+        pub preemptive_circuits: PreemptiveCircuitConfig,
+        ///
+        pub guardmgr: tor_guardmgr::TestConfig,
+    }
+    impl AsRef<[BridgeConfig]> for TestConfig {
+        fn as_ref(&self) -> &[BridgeConfig] {
+            &self.guardmgr.bridges
+        }
+    }
+    impl AsRef<FallbackList> for TestConfig {
+        fn as_ref(&self) -> &FallbackList {
+            &self.guardmgr.fallbacks
+        }
+    }
+    impl GuardMgrConfig for TestConfig {
+        fn bridges_enabled(&self) -> bool {
+            self.guardmgr.bridges_enabled()
+        }
+    }
+    impl CircMgrConfig for TestConfig {
+        fn path_rules(&self) -> &PathConfig { &self.path_rules }
+        fn circuit_timing(&self) -> &CircuitTiming { &self.circuit_timing }
+        fn preemptive_circuits(&self) -> &PreemptiveCircuitConfig { &self.preemptive_circuits }
+    }
+}
+
 #[cfg(test)]
 mod test {
     // @@ begin test lint list maintained by maint/add_warning @@

crates/tor-circmgr/src/lib.rs

@@ -55,6 +55,9 @@ use std::sync::{Arc, Mutex, Weak};
 use std::time::{Duration, Instant};
 use tracing::{debug, error, info, trace, warn};
 
+#[cfg(feature = "testing")]
+pub use config::test_config::TestConfig;
+
 pub mod build;
 mod config;
 mod err;