Contract mock system

Cargo.toml

@@ -4,6 +4,7 @@ members = [
   "ethcontract-common",
   "ethcontract-derive",
   "ethcontract-generate",
+  "ethcontract-mock",
   "examples",
   "examples/documentation",
   "examples/generate",

ethcontract-generate/src/generate/methods.rs

@@ -29,8 +29,19 @@ fn expand_functions(cx: &Context) -> Result<TokenStream> {
         .functions()
         .map(|function| {
             let signature = function.abi_signature();
-            expand_function(cx, function, aliases.remove(&signature))
-                .with_context(|| format!("error expanding function '{}'", signature))
+
+            let alias = aliases.remove(&signature);
+            let name = alias.unwrap_or_else(|| util::safe_ident(&function.name.to_snake_case()));
+            let signature = function.abi_signature();
+            let selector = expand_selector(function.selector());
+            let inputs = expand_inputs(&function.inputs)
+                .with_context(|| format!("error expanding function '{}'", signature))?;
+            let input_types = expand_input_types(&function.inputs)
+                .with_context(|| format!("error expanding function '{}'", signature))?;
+            let outputs = expand_outputs(&function.outputs)
+                .with_context(|| format!("error expanding function '{}'", signature))?;
+
+            Ok((function, name, selector, inputs, input_types, outputs))
         })
         .collect::<Result<Vec<_>>>()?;
     if let Some(unused) = aliases.keys().next() {
@@ -40,13 +51,31 @@ fn expand_functions(cx: &Context) -> Result<TokenStream> {
         ));
     }
 
+    let methods = functions
+        .iter()
+        .map(|(function, name, selector, inputs, _, outputs)| {
+            expand_function(cx, function, name, selector, inputs, outputs)
+        });
+
     let methods_attrs = quote! { #[derive(Clone)] };
     let methods_struct = quote! {
         struct Methods {
             instance: self::ethcontract::dyns::DynInstance,
         }
     };
 
+    let signature_accessors =
+        functions
+            .iter()
+            .map(|(function, name, selector, _, input_types, outputs)| {
+                expand_signature_accessor(function, name, selector, input_types, outputs)
+            });
+
+    let signatures_attrs = quote! { #[derive(Clone, Copy)] };
+    let signatures_struct = quote! {
+        struct Signatures;
+    };
+
     if functions.is_empty() {
         // NOTE: The methods struct is still needed when there are no functions
         //   as it contains the the runtime instance. The code is setup this way
@@ -55,11 +84,19 @@ fn expand_functions(cx: &Context) -> Result<TokenStream> {
         return Ok(quote! {
             #methods_attrs
             #methods_struct
+
+            #signatures_attrs
+            #signatures_struct
         });
     }
 
     Ok(quote! {
         impl Contract {
+            /// Returns an object that allows accessing typed method signatures.
+            pub fn signatures() -> Signatures {
+                Signatures
+            }
+
             /// Retrieves a reference to type containing all the generated
             /// contract methods. This can be used for methods where the name
             /// would collide with a common method (like `at` or `deployed`).
@@ -68,13 +105,21 @@ fn expand_functions(cx: &Context) -> Result<TokenStream> {
             }
         }
 
+        /// Type containing signatures for all methods for generated contract type.
+        #signatures_attrs
+        pub #signatures_struct
+
+        impl Signatures {
+            #( #signature_accessors )*
+        }
+
         /// Type containing all contract methods for generated contract type.
         #methods_attrs
         pub #methods_struct
 
         #[allow(clippy::too_many_arguments, clippy::type_complexity)]
         impl Methods {
-            #( #functions )*
+            #( #methods )*
         }
 
         impl std::ops::Deref for Contract {
@@ -86,10 +131,15 @@ fn expand_functions(cx: &Context) -> Result<TokenStream> {
     })
 }
 
-fn expand_function(cx: &Context, function: &Function, alias: Option<Ident>) -> Result<TokenStream> {
-    let name = alias.unwrap_or_else(|| util::safe_ident(&function.name.to_snake_case()));
+fn expand_function(
+    cx: &Context,
+    function: &Function,
+    name: &Ident,
+    selector: &TokenStream,
+    inputs: &TokenStream,
+    outputs: &TokenStream,
+) -> TokenStream {
     let signature = function.abi_signature();
-    let selector = expand_selector(function.selector());
 
     let doc_str = cx
         .contract
@@ -102,8 +152,6 @@ fn expand_function(cx: &Context, function: &Function, alias: Option<Ident>) -> R
         .unwrap_or("Generated by `ethcontract`");
     let doc = util::expand_doc(doc_str);
 
-    let input = expand_inputs(&function.inputs)?;
-    let outputs = expand_fn_outputs(&function.outputs)?;
     let (method, result_type_name) = match function.state_mutability {
         StateMutability::Pure | StateMutability::View => {
             (quote! { view_method }, quote! { DynViewMethodBuilder })
@@ -113,13 +161,32 @@ fn expand_function(cx: &Context, function: &Function, alias: Option<Ident>) -> R
     let result = quote! { self::ethcontract::dyns::#result_type_name<#outputs> };
     let arg = expand_inputs_call_arg(&function.inputs);
 
-    Ok(quote! {
+    quote! {
         #doc
-        pub fn #name(&self #input) -> #result {
+        pub fn #name(&self #inputs) -> #result {
             self.instance.#method(#selector, #arg)
                 .expect("generated call")
         }
-    })
+    }
+}
+
+fn expand_signature_accessor(
+    function: &Function,
+    name: &Ident,
+    selector: &TokenStream,
+    input_types: &TokenStream,
+    outputs: &TokenStream,
+) -> TokenStream {
+    let doc = util::expand_doc(&format!(
+        "Returns signature for method `{}`.",
+        function.signature()
+    ));
+    quote! {
+        #doc
+        pub fn #name(&self) -> self::ethcontract::contract::Signature<#input_types, #outputs> {
+            self::ethcontract::contract::Signature::new(#selector)
+        }
+    }
 }
 
 pub(crate) fn expand_inputs(inputs: &[Param]) -> Result<TokenStream> {
@@ -135,6 +202,14 @@ pub(crate) fn expand_inputs(inputs: &[Param]) -> Result<TokenStream> {
     Ok(quote! { #( , #params )* })
 }
 
+pub(crate) fn expand_input_types(inputs: &[Param]) -> Result<TokenStream> {
+    let params = inputs
+        .iter()
+        .map(|param| types::expand(&param.kind))
+        .collect::<Result<Vec<_>>>()?;
+    Ok(quote! { ( #( #params ,)* ) })
+}
+
 pub(crate) fn expand_inputs_call_arg(inputs: &[Param]) -> TokenStream {
     let names = inputs
         .iter()
@@ -143,7 +218,7 @@ pub(crate) fn expand_inputs_call_arg(inputs: &[Param]) -> TokenStream {
     quote! { ( #( #names ,)* ) }
 }
 
-fn expand_fn_outputs(outputs: &[Param]) -> Result<TokenStream> {
+fn expand_outputs(outputs: &[Param]) -> Result<TokenStream> {
     match outputs.len() {
         0 => Ok(quote! { () }),
         1 => types::expand(&outputs[0].kind),
@@ -216,14 +291,14 @@ mod tests {
     }
 
     #[test]
-    fn expand_fn_outputs_empty() {
-        assert_quote!(expand_fn_outputs(&[],).unwrap(), { () });
+    fn expand_outputs_empty() {
+        assert_quote!(expand_outputs(&[],).unwrap(), { () });
     }
 
     #[test]
-    fn expand_fn_outputs_single() {
+    fn expand_outputs_single() {
         assert_quote!(
-            expand_fn_outputs(&[Param {
+            expand_outputs(&[Param {
                 name: "a".to_string(),
                 kind: ParamType::Bool,
             }])
@@ -233,9 +308,9 @@ mod tests {
     }
 
     #[test]
-    fn expand_fn_outputs_multiple() {
+    fn expand_outputs_multiple() {
         assert_quote!(
-            expand_fn_outputs(&[
+            expand_outputs(&[
                 Param {
                     name: "a".to_string(),
                     kind: ParamType::Bool,

ethcontract-mock/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "ethcontract-mock"
+version = "0.14.0"
+authors = ["Gnosis developers <[email protected]>"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/gnosis/ethcontract-rs"
+homepage = "https://github.com/gnosis/ethcontract-rs"
+documentation = "https://docs.rs/ethcontract"
+description = """
+Tools for mocking ethereum contracts.
+"""
+
+[dependencies]
+ethcontract = { version = "0.14.0", path = "../ethcontract" }
+hex = "0.4"
+mockall = "0.10"
+rlp = "0.5"
+predicates = "1.0"
+
+[dev-dependencies]
+tokio = { version = "1.6", features = ["macros"] }
+ethcontract-derive = { version = "0.14.0", path = "../ethcontract-derive" }

ethcontract-mock/src/details/default.rs

@@ -0,0 +1,25 @@
+//! Helpers for building default values for tokens.
+
+use ethcontract::common::abi::{Bytes, Int, ParamType, Token, Uint};
+use ethcontract::Address;
+
+/// Builds a default value for the given solidity type.
+pub fn default(ty: &ParamType) -> Token {
+    match ty {
+        ParamType::Address => Token::Address(Address::default()),
+        ParamType::Bytes => Token::Bytes(Bytes::default()),
+        ParamType::Int(_) => Token::Int(Int::default()),
+        ParamType::Uint(_) => Token::Uint(Uint::default()),
+        ParamType::Bool => Token::Bool(false),
+        ParamType::String => Token::String(String::default()),
+        ParamType::Array(_) => Token::Array(Vec::new()),
+        ParamType::FixedBytes(n) => Token::FixedBytes(vec![0; *n]),
+        ParamType::FixedArray(ty, n) => Token::FixedArray(vec![default(ty); *n]),
+        ParamType::Tuple(tys) => default_tuple(tys.iter()),
+    }
+}
+
+/// Builds a default value for the given solidity tuple type.
+pub fn default_tuple<'a>(tys: impl Iterator<Item = &'a ParamType>) -> Token {
+    Token::Tuple(tys.map(default).collect())
+}