feat: Add predicate and script templates (#5238)

## Description

When DevRel creates more tutorials on predicates and scripts, it's not
ideal to use the same template designed for contracts and ask developers
to erase everything and start afresh. It's clearer to have developers
use a template tailored for the respective program type.

These templates are already compatible with existing `forc` commands
like

Predicate
1. `forc new --predicate MyPredicate`
2. `cargo generate --init fuellabs/sway templates/sway-predicate-test-rs
--name MyPredicate`

Script
1. `forc new --script MyScript`
2. `cargo generate --init fuellabs/sway templates/sway-script-test-rs
--name MyScript`

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

---------

Co-authored-by: IGI-111 <igi-111@protonmail.com>
Co-authored-by: Sophie Dankel <47993817+sdankel@users.noreply.github.com>

Author: 3 people

.github/workflows/ci.yml

@@ -287,7 +287,7 @@ jobs:
           crate: cargo-toml-lint
           version: '0.1'
       - name: Run Cargo.toml linter
-        run: git ls-files | grep Cargo.toml$ | grep -v 'templates/sway-test-rs' | xargs --verbose -n 1 cargo-toml-lint
+        run: git ls-files | grep Cargo.toml$ | grep -v 'templates/' | xargs --verbose -n 1 cargo-toml-lint
 
   cargo-fmt-check:
     runs-on: ubuntu-latest

docs/book/src/testing/testing-with-rust.md

@@ -51,6 +51,9 @@ placeholder in the template. Otherwise, `cargo-generate` automatically converts
 With `--force`, this means that both `my_fuel_project` and `my-fuel-project` are valid project names,
 depending on your needs.
 
+> _**Note**: `templates/sway-test-rs` can be replaced with `templates/sway-script-test-rs` or `templates/sway-predicate-test-rs` to generate a test
+> harness for scripts and predicates respectively.
+
 If all goes well, the output should look as follows:
 
 ```console

templates/README.md

@@ -1,4 +1,4 @@
 # templates
 
 A directory of useful templates for Sway developers, currently only home to the
-`sway-test-rs` `cargo generate` template for Sway + Rust integration testing.
+`sway-test-rs`, `sway-predicate-test-rs`, `sway-script-test-rs` `cargo generate` template for Sway + Rust integration testing.

templates/sway-predicate-test-rs/README.md

@@ -0,0 +1,11 @@
+# Rust + Sway integration testing
+
+A cargo-generate template that makes it easy to initialise Rust integration
+testing within an existing Sway project.
+
+This template is designed for Rust developers who wish to test integration of
+their Rust application and Sway code.
+
+See the [Testing with Rust](https://docs.fuel.network/docs/sway/testing/testing-with-rust/) chapter of [the Sway
+Book](https://fuellabs.github.io/sway/master) for a thorough guide on how to
+use this template.

templates/sway-predicate-test-rs/template/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "{{project-name}}"
+description = "A cargo-generate template for Rust + Sway integration testing."
+version = "0.1.0"
+edition = "2021"
+authors = ["{{authors}}"]
+license = "Apache-2.0"
+
+[dev-dependencies]
+fuels = { version = "0.53", features = ["fuel-core-lib"] }
+tokio = { version = "1.12", features = ["rt", "macros"] }
+
+[[test]]
+harness = true
+name = "integration_tests"
+path = "tests/harness.rs"

templates/sway-predicate-test-rs/template/cargo-generate.toml

@@ -0,0 +1,3 @@
+# Even though we don't need any custom configuration, the `cargo-generate.toml`
+# file is added to indicate the root of the default template within the
+# repository.

templates/sway-predicate-test-rs/template/tests/harness.rs

@@ -0,0 +1,71 @@
+use fuels::{accounts::{predicate::Predicate}, prelude::*};
+
+// Load abi from json
+abigen!(Predicate(
+    name = "MyPredicate",
+    abi = "out/debug/{{project-name}}-abi.json"
+));
+
+async fn get_predicate_instance() -> (WalletUnlocked, Predicate) {
+    let mut wallets = launch_custom_provider_and_get_wallets(
+        WalletsConfig::new(
+            Some(1),             /* Single wallet */
+            Some(1),             /* Single coin (UTXO) */
+            Some(1_000_000_000), /* Amount per coin */
+        ),
+        None,
+        None,
+    )
+    .await
+    .unwrap();
+
+    let wallet = wallets.pop().unwrap();
+
+    let provider = wallet.provider().clone().unwrap();
+
+    let bin_path = "./out/debug/{{project-name}}.bin";
+
+    let instance: Predicate = Predicate::load_from(bin_path).unwrap().with_provider(provider.clone());
+
+    (wallet, instance)
+}
+
+async fn check_balances(
+    wallet: &WalletUnlocked, 
+    instance: &Predicate, 
+    expected_wallet_balance: Option<u64>, 
+    expected_predicate_balance: Option<u64>,
+) -> (u64, u64) {
+    let wallet_bal = wallet.get_asset_balance(&AssetId::default()).await.unwrap();
+    let predicate_bal = instance.get_asset_balance(&AssetId::default()).await.unwrap();
+
+    if let Some(expected) = expected_wallet_balance {
+        assert_eq!(wallet_bal, expected);
+    }
+
+    if let Some(expected) = expected_predicate_balance {
+        assert_eq!(predicate_bal, expected);
+    }
+
+    (wallet_bal, predicate_bal)
+}
+
+#[tokio::test]
+async fn can_get_predicate_instance() {
+    let (wallet, instance) = get_predicate_instance().await;
+    let predicate_root = instance.address();
+
+    // Check balances before funding predicate
+    check_balances(&wallet, &instance, Some(1_000_000_000u64), None).await;
+
+    // Fund predicate from wallet
+    let _ = wallet.transfer(predicate_root, 1234, BASE_ASSET_ID, TxPolicies::default()).await;
+
+    // Check balances after funding predicate
+    check_balances(&wallet, &instance, Some(999_998_766u64), Some(1234u64)).await;
+
+    let _ = instance.transfer(wallet.address(), 1234, BASE_ASSET_ID, TxPolicies::default()).await;
+
+    // Check balances after transfering funds out of predicate
+    check_balances(&wallet, &instance, Some(1_000_000_000u64), Some(0u64)).await;
+}

templates/sway-script-test-rs/README.md

@@ -0,0 +1,11 @@
+# Rust + Sway integration testing
+
+A cargo-generate template that makes it easy to initialise Rust integration
+testing within an existing Sway project.
+
+This template is designed for Rust developers who wish to test integration of
+their Rust application and Sway code.
+
+See the [Testing with Rust](https://docs.fuel.network/docs/sway/testing/testing-with-rust/) chapter of [the Sway
+Book](https://fuellabs.github.io/sway/master) for a thorough guide on how to
+use this template.

templates/sway-script-test-rs/template/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "{{project-name}}"
+description = "A cargo-generate template for Rust + Sway integration testing."
+version = "0.1.0"
+edition = "2021"
+authors = ["{{authors}}"]
+license = "Apache-2.0"
+
+[dev-dependencies]
+fuels = { version = "0.53", features = ["fuel-core-lib"] }
+tokio = { version = "1.12", features = ["rt", "macros"] }
+
+[[test]]
+harness = true
+name = "integration_tests"
+path = "tests/harness.rs"

templates/sway-script-test-rs/template/cargo-generate.toml

@@ -0,0 +1,3 @@
+# Even though we don't need any custom configuration, the `cargo-generate.toml`
+# file is added to indicate the root of the default template within the
+# repository.

templates/sway-script-test-rs/template/tests/harness.rs

@@ -0,0 +1,45 @@
+use fuels::prelude::*;
+
+// Load abi from json
+abigen!(Script(
+    name = "MyScript",
+    abi = "out/debug/{{project-name}}-abi.json"
+));
+
+async fn get_script_instance() -> MyScript<WalletUnlocked> {
+    // Launch a local network
+    let mut wallets = launch_custom_provider_and_get_wallets(
+        WalletsConfig::new(
+            Some(1),             /* Single wallet */
+            Some(1),             /* Single coin (UTXO) */
+            Some(1_000_000_000), /* Amount per coin */
+        ),
+        None,
+        None,
+    )
+    .await;
+    let wallet = wallets.pop().unwrap();
+
+    let bin_path = "./out/debug/{{project-name}}.bin";
+
+    let instance = MyScript::new(wallet.clone(), bin_path);
+
+    instance
+}
+
+#[tokio::test]
+async fn can_get_script_instance() {
+    const LUCKY_NUMBER: u64 = 777; 
+    let configurables = MyScriptConfigurables::new().with_SECRET_NUMBER(LUCKY_NUMBER.clone());
+    
+    let instance = get_script_instance().await;
+    
+    // Now you have an instance of your script
+    let response = instance.with_configurables(configurables).main().call().await.unwrap();
+
+    assert_eq!(response.value, LUCKY_NUMBER);
+
+    // You can print logs from scripts to debug
+    let logs = response.decode_logs();
+    println!("{:?}", logs);
+}