Add basic workspace example (stellar#281)

Author: leighmcculloch

Diff for: workspace/Cargo.lock

@@ -0,0 +1,30 @@
+[workspace]
+resolver = "2"
+
+members = [
+    "contract_a_interface",
+    "contract_a",
+    "contract_b",
+]
+
+[workspace.package]
+version = "0.0.0"
+
+[workspace.dependencies]
+soroban-sdk = { version = "0.9.2" }
+soroban-workspace-contract-a-interface = { path = "contract_a_interface" }
+soroban-workspace-contract-a = { path = "contract_a" }
+
+[profile.release]
+opt-level = "z"
+overflow-checks = true
+debug = 0
+strip = "symbols"
+debug-assertions = false
+panic = "abort"
+codegen-units = 1
+lto = true
+
+[profile.release-with-logs]
+inherits = "release"
+debug-assertions = true

Diff for: workspace/Cargo.toml

@@ -0,0 +1,16 @@
+default: build
+
+all: test
+
+test:
+	cargo test
+
+build:
+	soroban contract build
+	@ls -l target/wasm32-unknown-unknown/release/*.wasm
+
+fmt:
+	cargo fmt --all
+
+clean:
+	cargo clean

Diff for: workspace/Makefile

@@ -0,0 +1,22 @@
+[package]
+name = "soroban-workspace-contract-a"
+version.workspace = true
+authors = ["Stellar Development Foundation <[email protected]>"]
+license = "Apache-2.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+doctest = false
+
+[features]
+testutils = []
+
+[dependencies]
+soroban-sdk = { workspace = true }
+soroban-workspace-contract-a-interface = { workspace = true }
+
+[dev_dependencies]
+soroban-sdk = { workspace = true, features = ["testutils"] }
+soroban-workspace-contract-a-interface = { workspace = true, features = ["testutils"] }

Diff for: workspace/contract_a/Cargo.toml

@@ -0,0 +1,14 @@
+#![no_std]
+
+use soroban_sdk::{contract, contractimpl};
+use soroban_workspace_contract_a_interface::ContractAInterface;
+
+#[contract]
+pub struct ContractA;
+
+#[contractimpl]
+impl ContractAInterface for ContractA {
+    fn add(x: u32, y: u32) -> u32 {
+        x.checked_add(y).expect("no overflow")
+    }
+}

Diff for: workspace/contract_a/src/lib.rs

@@ -0,0 +1,20 @@
+[package]
+name = "soroban-workspace-contract-a-interface"
+version.workspace = true
+authors = ["Stellar Development Foundation <[email protected]>"]
+license = "Apache-2.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["rlib"]
+doctest = false
+
+[features]
+testutils = []
+
+[dependencies]
+soroban-sdk = { workspace = true }
+
+[dev_dependencies]
+soroban-sdk = { workspace = true, features = ["testutils"] }

Diff for: workspace/contract_a_interface/Cargo.toml

@@ -0,0 +1,8 @@
+#![no_std]
+
+use soroban_sdk::contractclient;
+
+#[contractclient(name = "ContractAClient")]
+pub trait ContractAInterface {
+    fn add(x: u32, y: u32) -> u32;
+}

Diff for: workspace/contract_a_interface/src/lib.rs

@@ -0,0 +1,20 @@
+[package]
+name = "soroban-workspace-contract-b"
+version.workspace = true
+authors = ["Stellar Development Foundation <[email protected]>"]
+license = "Apache-2.0"
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["cdylib"]
+doctest = false
+
+[dependencies]
+soroban-sdk = { workspace = true }
+soroban-workspace-contract-a-interface = { workspace = true }
+
+[dev_dependencies]
+soroban-sdk = { workspace = true, features = ["testutils"] }
+soroban-workspace-contract-a-interface = { workspace = true, features = ["testutils"] }
+soroban-workspace-contract-a = { workspace = true, features = ["testutils"] }

Diff for: workspace/contract_b/Cargo.toml

@@ -0,0 +1,17 @@
+#![no_std]
+
+use soroban_sdk::{contract, contractimpl, Address, Env};
+use soroban_workspace_contract_a_interface::ContractAClient;
+
+#[contract]
+pub struct ContractB;
+
+#[contractimpl]
+impl ContractB {
+    pub fn add_with(env: Env, contract: Address, x: u32, y: u32) -> u32 {
+        let client = ContractAClient::new(&env, &contract);
+        client.add(&x, &y)
+    }
+}
+
+mod test;

Diff for: workspace/contract_b/src/lib.rs

@@ -0,0 +1,25 @@
+#![cfg(test)]
+
+use soroban_sdk::Env;
+
+use crate::{ContractB, ContractBClient};
+
+use soroban_workspace_contract_a::ContractA;
+
+#[test]
+fn test() {
+    let env = Env::default();
+
+    // Register contract A using the native contract imported.
+    let contract_a_id = env.register_contract(None, ContractA);
+
+    // Register contract B defined in this crate.
+    let contract_b_id = env.register_contract(None, ContractB);
+
+    // Create a client for calling contract B.
+    let client = ContractBClient::new(&env, &contract_b_id);
+
+    // Invoke contract B via its client. Contract B will invoke contract A.
+    let sum = client.add_with(&contract_a_id, &5, &7);
+    assert_eq!(sum, 12);
+}