Add test_utils

We add a utility function needed by upcoming `KVStore` implementation
tests.

Author: tnull

lightning-storage/src/lib.rs

@@ -8,3 +8,6 @@
 #![deny(unsafe_code)]
 
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
+
+#[cfg(test)]
+mod test_utils;

lightning-storage/src/test_utils.rs

@@ -0,0 +1,34 @@
+use lightning::util::persist::KVStore;
+
+use rand::{thread_rng, RngCore};
+
+pub(crate) fn do_read_write_remove_list_persist<K: KVStore>(kv_store: &K) {
+	use lightning::util::ser::Readable;
+
+	let mut data = [0; 32];
+	thread_rng().fill_bytes(&mut data);
+
+
+	let namespace = "testspace";
+	let key = "testkey";
+
+	// Test the basic KVStore operations.
+	kv_store.write(namespace, key, &data).unwrap();
+
+	// Test empty namespace is allowed, but not empty key.
+	kv_store.write("", key, &data).unwrap();
+	assert!(kv_store.write(namespace, "", &data).is_err());
+
+	let listed_keys = kv_store.list(namespace).unwrap();
+	assert_eq!(listed_keys.len(), 1);
+	assert_eq!(listed_keys[0], key);
+
+	let mut reader = kv_store.read(namespace, key).unwrap();
+	let read_data: [u8; 32] = Readable::read(&mut reader).unwrap();
+	assert_eq!(data, read_data);
+
+	kv_store.remove(namespace, key).unwrap();
+
+	let listed_keys = kv_store.list(namespace).unwrap();
+	assert_eq!(listed_keys.len(), 0);
+}