[E2E] Add create_call_builder for testing on-chain contracts

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Custom signature topic in Events - [#2031](https://github.com/paritytech/ink/pull/2031)
 - Linter: `non_fallible_api` lint - [#2004](https://github.com/paritytech/ink/pull/2004)
 - Linter: Publish the linting crates on crates.io - [#2060](https://github.com/paritytech/ink/pull/2060)
+- [E2E] Added `create_call_builder` for testing existing contracts - [#2075](https://github.com/paritytech/ink/pull/2075)
 
 ### Fixed
 - Fix the `StorageVec` type by excluding the `len_cached` field from its type info - [#2052](https://github.com/paritytech/ink/pull/2052)

crates/e2e/src/lib.rs

@@ -82,6 +82,11 @@ pub use {
     drink_client::Client as DrinkClient,
 };
 
+use ink_env::{
+    call::FromAccountId,
+    ContractEnv,
+    Environment,
+};
 use pallet_contracts_primitives::{
     ContractExecResult,
     ContractInstantiateResult,
@@ -128,6 +133,21 @@ pub fn account_id(account: AccountKeyring) -> ink_primitives::AccountId {
         .expect("account keyring has a valid account id")
 }
 
+/// Creates a call builder builder for `Contract`, based on an account id.
+pub fn create_call_builder<Contract>(
+    acc_id: <<Contract as ContractEnv>::Env as Environment>::AccountId,
+) -> <Contract as ContractCallBuilder>::Type
+where
+    <Contract as ContractEnv>::Env: Environment,
+    Contract: ContractCallBuilder,
+    Contract: ContractEnv,
+    Contract::Type: FromAccountId<<Contract as ContractEnv>::Env>,
+{
+    <<Contract as ContractCallBuilder>::Type as FromAccountId<
+        <Contract as ContractEnv>::Env,
+    >>::from_account_id(acc_id)
+}
+
 /// Builds a contract and imports its scaffolded structure as a module.
 #[macro_export]
 macro_rules! build {

integration-tests/flipper/Cargo.toml

@@ -10,6 +10,7 @@ ink = { path = "../../crates/ink", default-features = false }
 
 [dev-dependencies]
 ink_e2e = { path = "../../crates/e2e" }
+hex-literal = { version = "0.4.1" }
 
 [lib]
 path = "lib.rs"

integration-tests/flipper/lib.rs

@@ -110,5 +110,50 @@ pub mod flipper {
 
             Ok(())
         }
+
+        /// This test illustrates how to test an existing on-chain contract.
+        ///
+        /// You can utilize this to e.g. create a snapshot of a production chain
+        /// and run the E2E tests against a deployed contract there.
+        /// This process is explained [here](https://use.ink/5.x/basics/contract-testing/chain-snapshot).
+        /// It requires a node to be run in the background, before executing the test.
+        ///
+        /// The test is run like this:
+        ///
+        /// ```
+        /// # The env variable needs to be set, otherwise `ink_e2e` will spawn a new
+        /// # node process for each test.
+        /// $ export CONTRACTS_NODE_URL=ws://127.0.0.1:9944
+        ///
+        /// $ cargo test --features e2e-tests e2e_test_deployed_contract
+        /// ```
+        #[ink_e2e::test]
+        #[ignore]
+        async fn e2e_test_deployed_contract<Client: E2EBackend>(
+            mut client: Client,
+        ) -> E2EResult<()> {
+            // given
+            // You can take a SS58 address and convert it to hex using the `subkey` tool:
+            //
+            // ```
+            // subkey inspect 5D4zzvxGZq4wx3SYuaDomSMSAS1h1Knm35gz62UAk4Tqscey
+            //   ...
+            //   Public key (hex):   0x2c75f0aa09dbfbfd49e6286a0f2edd3b4913f04a58b13391c79e96782f5713e3
+            // ```
+            let acc_id = hex_literal::hex!(
+                "2c75f0aa09dbfbfd49e6286a0f2edd3b4913f04a58b13391c79e96782f5713e3"
+            );
+            let acc_id = AccountId::from(acc_id);
+
+            // when
+            // Invoke `Flipper::get()` from Bob
+            let call_builder = ink_e2e::create_call_builder::<Flipper>(acc_id);
+            let get = call_builder.get();
+            let get_res = client.call(&ink_e2e::bob(), &get).dry_run().await?;
+
+            // then
+            assert!(matches!(get_res.return_value(), true));
+            Ok(())
+        }
     }
 }