drink_test_macro/

lib.rs

//! Procedural macro providing a `#[drink::test]` attribute for `drink`-based contract testing.

#![warn(missing_docs)]

mod bundle_provision;
mod contract_building;

use darling::{ast::NestedMeta, FromMeta};
use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use quote::quote;
use syn::{ItemEnum, ItemFn};

use crate::contract_building::build_contracts;

type SynResult<T> = Result<T, syn::Error>;

/// Defines a drink!-based test.
///
/// # Requirements
///
/// - Your crate must have `drink` in its dependencies (and it shouldn't be renamed).
/// - You mustn't import `drink::test` in the scope, where the macro is used. In other words, you
///   should always use the macro only with a qualified path `#[drink::test]`.
/// - Your crate cannot be part of a cargo workspace.
///
/// # Impact
///
/// This macro will take care of building all needed contracts for the test. The building process
/// will be executed during compile time.
///
/// Contracts to be built:
///  - current cargo package if contains a `ink-as-dependency` feature
///  - all dependencies declared in the `Cargo.toml` file with the `ink-as-dependency` feature
///    enabled (works with non-local packages as well).
///
/// ## Compilation features
///
/// 1. The root contract package (if any) is assumed to be built without any features.
///
/// 2. All contract dependencies will be built with a union of all features enabled on that package (through potentially
///    different configurations or dependency paths), **excluding** `ink-as-dependency` and `std` features.
///
/// # Creating a session object
///
/// The macro will also create a new mutable session object and pass it to the decorated function by value. You can
/// configure which sandbox should be used (by specifying a path to a type implementing
/// `ink_sandbox::Sandbox` trait. Thus, your testcase function should accept a single argument:
/// `mut session: Session<_>`.
///
/// By default, the macro will use `drink::minimal::MinimalSandbox`.
///
/// # Example
///
/// ```rust, ignore
/// #[drink::test]
/// fn testcase(mut session: Session<MinimalSandbox>) {
///     session
///         .deploy_bundle(&get_bundle(), "new", NO_ARGS, NO_SALT, NO_ENDOWMENT)
///         .unwrap();
/// }
/// ```
#[proc_macro_attribute]
pub fn test(attr: TokenStream, item: TokenStream) -> TokenStream {
    match test_internal(attr.into(), item.into()) {
        Ok(ts) => ts.into(),
        Err(e) => e.to_compile_error().into(),
    }
}

#[derive(FromMeta)]
struct TestAttributes {
    sandbox: Option<syn::Path>,
}

/// Auxiliary function to enter ?-based error propagation.
fn test_internal(attr: TokenStream2, item: TokenStream2) -> SynResult<TokenStream2> {
    let item_fn = syn::parse2::<ItemFn>(item)?;
    let macro_args = TestAttributes::from_list(&NestedMeta::parse_meta_list(attr)?)?;

    build_contracts();

    let fn_vis = item_fn.vis;
    let fn_attrs = item_fn.attrs;
    let fn_block = item_fn.block;
    let fn_name = item_fn.sig.ident;
    let fn_async = item_fn.sig.asyncness;
    let fn_generics = item_fn.sig.generics;
    let fn_output = item_fn.sig.output;
    let fn_const = item_fn.sig.constness;
    let fn_unsafety = item_fn.sig.unsafety;

    let sandbox = macro_args
        .sandbox
        .unwrap_or(syn::parse2(quote! { ::drink::minimal::MinimalSandbox })?);

    Ok(quote! {
        #[test]
        #(#fn_attrs)*
        #fn_vis #fn_async #fn_const #fn_unsafety fn #fn_name #fn_generics () #fn_output {
            let mut session = Session::<#sandbox>::default();
            #fn_block
        }
    })
}

/// Defines a contract bundle provider.
///
/// # Requirements
///
/// - Your crate cannot be part of a cargo workspace.
/// - Your crate must have `drink` in its dependencies (and it shouldn't be renamed).
/// - The attributed enum must not:
///     - be generic
///     - have variants
///     - have any attributes conflicting with `#[derive(Copy, Clone, PartialEq, Eq, Debug)]`
///
/// # Impact
///
/// This macro is intended to be used as an attribute of some empty enum. It will build all
/// contracts crates (with rules identical to those of `#[drink::test]`), and populate the decorated
/// enum with variants, one per built contract.
///
/// If the current crate is a contract crate, the enum will receive a method `local()` that returns
/// the contract bundle for the current crate.
///
/// Besides that, the enum will receive a method `bundle(self)` that returns the contract bundle
/// for corresponding contract variant.
///
/// Both methods return `DrinkResult<ContractBundle>`.
///
/// # Example
///
/// ```rust, ignore
/// #[drink::contract_bundle_provider]
/// enum BundleProvider {}
///
/// fn testcase() {
///     Session::<MinimalSandbox>::default()
///         .deploy_bundle_and(BundleProvider::local()?, "new", NO_ARGS, NO_SALT, NO_ENDOWMENT)
///         .deploy_bundle_and(BundleProvider::AnotherContract.bundle()?, "new", NO_ARGS, NO_SALT, NO_ENDOWMENT)
///         .unwrap();
/// }
/// ```
#[proc_macro_attribute]
pub fn contract_bundle_provider(attr: TokenStream, item: TokenStream) -> TokenStream {
    match contract_bundle_provider_internal(attr.into(), item.into()) {
        Ok(ts) => ts.into(),
        Err(e) => e.to_compile_error().into(),
    }
}

/// Auxiliary function to enter ?-based error propagation.
fn contract_bundle_provider_internal(
    _attr: TokenStream2,
    item: TokenStream2,
) -> SynResult<TokenStream2> {
    let enum_item = parse_bundle_enum(item)?;
    let bundle_registry = build_contracts();
    Ok(bundle_registry.generate_bundle_provision(enum_item))
}

fn parse_bundle_enum(item: TokenStream2) -> SynResult<ItemEnum> {
    let enum_item = syn::parse2::<ItemEnum>(item)?;

    if !enum_item.generics.params.is_empty() {
        return Err(syn::Error::new_spanned(
            enum_item.generics.params,
            "ContractBundleProvider must not be generic",
        ));
    }
    if !enum_item.variants.is_empty() {
        return Err(syn::Error::new_spanned(
            enum_item.variants,
            "ContractBundleProvider must not have variants",
        ));
    }

    Ok(enum_item)
}