refactor(probe): name the inspector constructor bound

The three argument constructor signature was written out in the public
bound, the scripted test alias and the test stub. A BuildInspector trait
states it once.

Renames the registry lookup to find_inspector_builder: it builds nothing,
it answers whether a chain has a probe and how.

Author: haiyuechen-nearone

crates/foreign-chain-health-check/src/probe.rs

@@ -101,20 +101,12 @@ impl ProbeReport {
     }
 }
 
-/// Probe every configured provider concurrently, building each provider's inspector with
-/// `new_inspector`. The node injects [`rpc_inspector`].
-///
 /// Each provider is tried up to `max_retries` times, `timeout_sec` per try, and only for as long as
 /// the failures stay transient. This returns within the largest configured `timeout_sec *
 /// max_retries`, plus the [`foreign_chain_inspector::RETRY_BACKOFF`] between tries.
 pub async fn probe_all_providers<I>(
     config: &ForeignChainsConfig,
-    new_inspector: impl Fn(
-        ForeignChain,
-        &ForeignChainConfig,
-        &ForeignChainProviderConfig,
-    ) -> anyhow::Result<I>
-    + Sync,
+    new_inspector: impl BuildInspector<I>,
 ) -> ProbeReport
 where
     I: NetworkFingerprintInspector + Clone + Send + Sync + 'static,
@@ -124,7 +116,7 @@ where
     let probe_attempts = config
         .iter_chains()
         .map(|(chain, chain_config)| async move {
-            if new_rpc_inspector(chain).is_none() {
+            if find_inspector_builder(chain).is_none() {
                 return rows_of(chain, chain_config, ProviderStatus::ProbeNotImplemented);
             }
             probe_chain(chain, chain_config, |provider| {
@@ -139,13 +131,24 @@ where
         .into()
 }
 
+/// Builds one provider's inspector. The node supplies [`rpc_inspector`]; a test supplies its own.
+pub trait BuildInspector<I>:
+    Fn(ForeignChain, &ForeignChainConfig, &ForeignChainProviderConfig) -> anyhow::Result<I> + Sync
+{
+}
+
+impl<F, I> BuildInspector<I> for F where
+    F: Fn(ForeignChain, &ForeignChainConfig, &ForeignChainProviderConfig) -> anyhow::Result<I>
+        + Sync
+{
+}
+
 /// Builds one provider's inspector for a chain whose probe exists.
-type NewRpcInspector =
+type InspectorBuilder =
     fn(&ForeignChainConfig, &ForeignChainProviderConfig) -> anyhow::Result<RpcInspector>;
 
-/// How to build a chain's inspector, or `None` when no probe exists for the chain. The single
-/// source of truth for which chains the probe covers.
-fn new_rpc_inspector(chain: ForeignChain) -> Option<NewRpcInspector> {
+/// The single source of truth for which chains the probe covers.
+fn find_inspector_builder(chain: ForeignChain) -> Option<InspectorBuilder> {
     Some(match chain {
         ForeignChain::Starknet => |_, provider| {
             Ok(RpcInspector::Starknet(StarknetInspector::new(http_client(
@@ -255,7 +258,7 @@ pub fn rpc_inspector(
     chain_config: &ForeignChainConfig,
     provider: &ForeignChainProviderConfig,
 ) -> anyhow::Result<RpcInspector> {
-    let Some(new_inspector) = new_rpc_inspector(chain) else {
+    let Some(new_inspector) = find_inspector_builder(chain) else {
         anyhow::bail!("no probe exists for {chain:?}");
     };
     new_inspector(chain_config, provider)
@@ -592,14 +595,7 @@ mod tests {
     // The scripted tests below run under a paused tokio clock; see `foreign_chain_inspector::mock`
     // for why that must never be combined with the httpmock or tonic tests in this module.
 
-    type NewScripted = Box<
-        dyn Fn(
-                ForeignChain,
-                &ForeignChainConfig,
-                &ForeignChainProviderConfig,
-            ) -> anyhow::Result<ScriptedInspector>
-            + Sync,
-    >;
+    type NewScripted = Box<dyn BuildInspector<ScriptedInspector>>;
 
     /// A `new_inspector` for scripted tests: each provider gets the inspector scripted for its
     /// URL, and a provider without one fails its setup.