Add btc-finality integration tests

contracts/btc-finality/tests/integration.rs

@@ -0,0 +1,35 @@
+use cosmwasm_std::{ContractResult, Response};
+use cosmwasm_vm::testing::{instantiate, mock_env, mock_info, mock_instance};
+
+use btc_finality::msg::InstantiateMsg;
+
+// wasm binary lite version
+static WASM: &[u8] = include_bytes!("../../../artifacts/btc_finality.wasm");
+/// Wasm size limit: https://github.com/CosmWasm/wasmd/blob/main/x/wasm/types/validation.go#L24-L25
+const MAX_WASM_SIZE: usize = 800 * 1024; // 800 KB
+
+const CREATOR: &str = "creator";
+
+#[test]
+fn wasm_size_limit_check() {
+    assert!(
+        WASM.len() < MAX_WASM_SIZE,
+        "BTC finality contract wasm binary is too large: {} (target: {})",
+        WASM.len(),
+        MAX_WASM_SIZE
+    );
+}
+
+#[test]
+fn instantiate_works() {
+    let mut deps = mock_instance(WASM, &[]);
+
+    let msg = InstantiateMsg {
+        params: None,
+        admin: None,
+    };
+    let info = mock_info(CREATOR, &[]);
+    let res: ContractResult<Response> = instantiate(&mut deps, mock_env(), info, msg);
+    let msgs = res.unwrap().messages;
+    assert_eq!(0, msgs.len());
+}