feat(fuzz): add dedicated chainman setup fuzz target

Add a new fuzz target for testing chainstate manager initialization.

Author: alexanderwiederin

fuzz/Cargo.toml

@@ -25,6 +25,13 @@ test = false
 doc = false
 bench = false
 
+[[bin]]
+name = "fuzz_target_chainman_setup"
+path = "fuzz_targets/fuzz_target_chainman_setup.rs"
+test = false
+doc = false
+bench = false
+
 [[bin]]
 name = "fuzz_target_verify"
 path = "fuzz_targets/fuzz_target_verify.rs"
@@ -38,3 +45,4 @@ path = "fuzz_targets/fuzz_target_block.rs"
 test = false
 doc = false
 bench = false
+

fuzz/fuzz_targets/fuzz_target_chainman_setup.rs

@@ -0,0 +1,37 @@
+#![no_main]
+use std::sync::Arc;
+
+use arbitrary::Arbitrary;
+use bitcoinkernel::ChainType;
+use fuzz_common::{cleanup_dir, create_chainstate_manager, init_logging, ChainstateSetupConfig};
+use libfuzzer_sys::fuzz_target;
+
+#[derive(Debug, Arbitrary)]
+pub struct SetupInput {
+    pub config: ChainstateSetupConfig,
+}
+
+pub fn create_simple_context(chain_type: ChainType) -> std::sync::Arc<bitcoinkernel::Context> {
+    use bitcoinkernel::ContextBuilder;
+
+    Arc::new(
+        ContextBuilder::new()
+            .chain_type(chain_type)
+            .build()
+            .unwrap(),
+    )
+}
+
+fuzz_target!(|data: SetupInput| {
+    init_logging();
+
+    let context = create_simple_context(data.config.chain_type.clone().into());
+    let data_dir = data.config.create_fuzz_data_dir("setup");
+
+    let Some(chainman) = create_chainstate_manager(&context, &data.config, &data_dir) else {
+        return;
+    };
+
+    drop(chainman);
+    cleanup_dir(&data_dir);
+});