Fungible Token (FT)

Example implementation of a Fungible Token contract which uses near-contract-standards and simulation tests. This is a contract-only example.

Prerequisites

If you're using Gitpod, you can skip this step.

1. Make sure Rust is installed per the prerequisites in near-sdk-rs
2. Ensure near-cli is installed by running near --version. If not installed, install with: npm install -g near-cli

Building

To build run:

./build.sh

Testing

As with many Rust libraries and contracts, there are tests in the main fungible token implementation at ft/src/lib.rs.

Additionally, this project has simulation tests in tests/sim. Simulation tests allow testing cross-contract calls, which is crucial to ensuring that the ft_transfer_call function works properly. These simulation tests are the reason this project has the file structure it does. Note that the root project has a Cargo.toml which sets it up as a workspace. ft and test-contract-defi are both small & focused contract projects, the latter only existing for simulation tests. The root project imports near-sdk-sim and tests interaction between these contracts.

You can run all these tests with one command:

cargo test

If you want to run only simulation tests, you can use cargo test simulation, since all the simulation tests include "simulation" in their names.

Notes

• The maximum balance value is limited by U128 (2**128 - 1).
• JSON calls should pass U128 as a base-10 string. E.g. "100".
• This does not include escrow functionality, as ft_transfer_call provides a superior approach. An escrow system can, of course, be added as a separate contract or additional functionality within this contract.

No AssemblyScript?

near-contract-standards is currently Rust-only. We strongly suggest using this library to create your own Fungible Token contract to ensure it works as expected.

Someday NEAR core or community contributors may provide a similar library for AssemblyScript, at which point this example will be updated to include both a Rust and AssemblyScript version.

Contributing

When making changes to the files in ft or test-contract-defi, remember to use ./build.sh to compile all contracts and copy the output to the res folder. If you forget this, the simulation tests will not use the latest versions.