Fix unit tests and add no-std check

Cargo.toml

@@ -13,6 +13,7 @@ codec = { package = "parity-scale-codec", version = "2.0.0", default-features =
 hex = { version = "0.4", default-features = false, features = ["alloc"] }
 libsecp256k1 = { version = "0.7.0", features = ["static-context"], default-features = false }
 mmr-lib = { package = "ckb-merkle-mountain-range", default-features = false, version = "0.3.1" }
+# getrandom = { version = "0.2", features = ["js"] }
 
 [dev-dependencies]
 hex-literal = "0.3.1"

Makefile

@@ -0,0 +1,2 @@
+check:
+	cargo check --no-default-features --target=wasm32-unknown-unknown

src/commitment.rs

@@ -1,6 +1,4 @@
 #[cfg(not(feature = "std"))]
-use alloc::string::String;
-#[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
 #[cfg(not(feature = "std"))]
 use core::cmp;

src/lib.rs

@@ -7,8 +7,6 @@ extern crate alloc;
 use alloc::string::String;
 #[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
-#[cfg(not(feature = "std"))]
-use core::result;
 
 use beefy_merkle_tree::{merkle_root, verify_proof, Keccak256};
 use borsh::{BorshDeserialize, BorshSerialize};

src/mmr.rs

@@ -2,8 +2,6 @@
 use alloc::vec;
 #[cfg(not(feature = "std"))]
 use alloc::vec::Vec;
-#[cfg(not(feature = "std"))]
-use core::convert::Into;
 
 use crate::BeefyNextAuthoritySet;
 use beefy_merkle_tree::{Hash, Keccak256};
@@ -333,7 +331,7 @@ mod tests {
 		];
 
 		for i in 0..leaves.len() {
-			assert_eq!(verify_leaf_proof(root, leaves[i].clone(), proofs[i].clone()).is_ok(), true);
+			assert_eq!(verify_leaf_proof(root, leaves[i].clone(), proofs[i].clone()), Ok(true));
 		}
 	}
 }