Implements mocking of runtime apis (#5448)

* Implements mocking of runtime apis

This pr adds support for easily mock runtime api implementations for
tests by using the `mock_impl_runtime_apis!` macro. The syntax is
similar to `impl_runtime_apis!`. The mocked implementation automatically
implements `ApiExt`, `ApiErrorExt` and `Core` as these are required by
the runtime api traits, but not required in tests or only a subset of them.

* Fix warnings

* Update primitives/api/proc-macro/src/utils.rs

Co-Authored-By: Nikolay Volf <nikvolf@gmail.com>

* Review feedback

Co-authored-by: Nikolay Volf <nikvolf@gmail.com>

substrate/primitives/api/test/tests/ui/mock_only_error_associated_type.rs

@@ -0,0 +1,19 @@
+use substrate_test_runtime_client::runtime::Block;
+
+sp_api::decl_runtime_apis! {
+	pub trait Api {
+		fn test(data: u64);
+	}
+}
+
+struct MockApi;
+
+sp_api::mock_impl_runtime_apis! {
+	impl Api<Block> for MockApi {
+		type OtherData = u32;
+
+		fn test(data: u64) {}
+	}
+}
+
+fn main() {}

substrate/primitives/api/test/tests/ui/mock_only_error_associated_type.stderr

@@ -0,0 +1,5 @@
+error: Only associated type with name `Error` is allowed
+  --> $DIR/mock_only_error_associated_type.rs:13:3
+   |
+13 |         type OtherData = u32;
+   |         ^^^^

substrate/primitives/api/test/tests/ui/mock_only_one_block_type.rs

@@ -0,0 +1,27 @@
+use substrate_test_runtime_client::runtime::Block;
+
+struct Block2;
+
+sp_api::decl_runtime_apis! {
+	pub trait Api {
+		fn test(data: u64);
+	}
+
+	pub trait Api2 {
+		fn test(data: u64);
+	}
+}
+
+struct MockApi;
+
+sp_api::mock_impl_runtime_apis! {
+	impl Api<Block> for MockApi {
+		fn test(data: u64) {}
+	}
+
+	impl Api2<Block2> for MockApi {
+		fn test(data: u64) {}
+	}
+}
+
+fn main() {}

substrate/primitives/api/test/tests/ui/mock_only_one_block_type.stderr

@@ -0,0 +1,19 @@
+error: Block type should be the same between all runtime apis.
+  --> $DIR/mock_only_one_block_type.rs:22:12
+   |
+22 |     impl Api2<Block2> for MockApi {
+   |               ^^^^^^
+
+error: First block type found here
+  --> $DIR/mock_only_one_block_type.rs:18:11
+   |
+18 |     impl Api<Block> for MockApi {
+   |              ^^^^^
+
+warning: unused import: `substrate_test_runtime_client::runtime::Block`
+ --> $DIR/mock_only_one_block_type.rs:1:5
+  |
+1 | use substrate_test_runtime_client::runtime::Block;
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: `#[warn(unused_imports)]` on by default

substrate/primitives/api/test/tests/ui/mock_only_one_error_type.rs

@@ -0,0 +1,29 @@
+use substrate_test_runtime_client::runtime::Block;
+
+sp_api::decl_runtime_apis! {
+	pub trait Api {
+		fn test(data: u64);
+	}
+
+	pub trait Api2 {
+		fn test(data: u64);
+	}
+}
+
+struct MockApi;
+
+sp_api::mock_impl_runtime_apis! {
+	impl Api<Block> for MockApi {
+		type Error = u32;
+
+		fn test(data: u64) {}
+	}
+
+	impl Api2<Block> for MockApi {
+		type Error = u64;
+
+		fn test(data: u64) {}
+	}
+}
+
+fn main() {}

substrate/primitives/api/test/tests/ui/mock_only_one_error_type.stderr

@@ -0,0 +1,27 @@
+error: Error type can not change between runtime apis
+  --> $DIR/mock_only_one_error_type.rs:23:3
+   |
+23 |         type Error = u64;
+   |         ^^^^
+
+error[E0277]: the trait bound `u32: std::convert::From<std::string::String>` is not satisfied
+  --> $DIR/mock_only_one_error_type.rs:15:1
+   |
+15 | / sp_api::mock_impl_runtime_apis! {
+16 | |     impl Api<Block> for MockApi {
+17 | |         type Error = u32;
+18 | |
+...  |
+26 | |     }
+27 | | }
+   | | ^
+   | | |
+   | |_the trait `std::convert::From<std::string::String>` is not implemented for `u32`
+   |   in this macro invocation
+   |
+   = help: the following implementations were found:
+             <u32 as std::convert::From<bool>>
+             <u32 as std::convert::From<char>>
+             <u32 as std::convert::From<h2::frame::reason::Reason>>
+             <u32 as std::convert::From<h2::frame::stream_id::StreamId>>
+           and 16 others

substrate/primitives/api/test/tests/ui/mock_only_one_self_type.rs

@@ -0,0 +1,26 @@
+use substrate_test_runtime_client::runtime::Block;
+
+sp_api::decl_runtime_apis! {
+	pub trait Api {
+		fn test(data: u64);
+	}
+
+	pub trait Api2 {
+		fn test(data: u64);
+	}
+}
+
+struct MockApi;
+struct MockApi2;
+
+sp_api::mock_impl_runtime_apis! {
+	impl Api<Block> for MockApi {
+		fn test(data: u64) {}
+	}
+
+	impl Api2<Block> for MockApi2 {
+		fn test(data: u64) {}
+	}
+}
+
+fn main() {}

substrate/primitives/api/test/tests/ui/mock_only_one_self_type.stderr

@@ -0,0 +1,19 @@
+error: Self type should not change between runtime apis
+  --> $DIR/mock_only_one_self_type.rs:21:23
+   |
+21 |     impl Api2<Block> for MockApi2 {
+   |                          ^^^^^^^^
+
+error: First self type found here
+  --> $DIR/mock_only_one_self_type.rs:17:22
+   |
+17 |     impl Api<Block> for MockApi {
+   |                         ^^^^^^^
+
+warning: unused import: `substrate_test_runtime_client::runtime::Block`
+ --> $DIR/mock_only_one_self_type.rs:1:5
+  |
+1 | use substrate_test_runtime_client::runtime::Block;
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+  = note: `#[warn(unused_imports)]` on by default

substrate/primitives/api/test/tests/ui/mock_only_self_reference.rs

@@ -0,0 +1,20 @@
+use substrate_test_runtime_client::runtime::Block;
+
+sp_api::decl_runtime_apis! {
+	pub trait Api {
+		fn test(data: u64);
+		fn test2(data: u64);
+	}
+}
+
+struct MockApi;
+
+sp_api::mock_impl_runtime_apis! {
+	impl Api<Block> for MockApi {
+		fn test(self, data: u64) {}
+
+		fn test2(&mut self, data: u64) {}
+	}
+}
+
+fn main() {}

substrate/primitives/api/test/tests/ui/mock_only_self_reference.stderr

@@ -0,0 +1,65 @@
+error: Only `&self` is supported!
+  --> $DIR/mock_only_self_reference.rs:14:11
+   |
+14 |         fn test(self, data: u64) {}
+   |                 ^^^^
+
+error: Only `&self` is supported!
+  --> $DIR/mock_only_self_reference.rs:16:12
+   |
+16 |         fn test2(&mut self, data: u64) {}
+   |                  ^
+
+error[E0053]: method `Api_test_runtime_api_impl` has an incompatible type for trait
+  --> $DIR/mock_only_self_reference.rs:12:1
+   |
+3  | / sp_api::decl_runtime_apis! {
+4  | |     pub trait Api {
+5  | |         fn test(data: u64);
+6  | |         fn test2(data: u64);
+7  | |     }
+8  | | }
+   | |_- type in trait
+...
+12 |   sp_api::mock_impl_runtime_apis! {
+   |   -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |   |
+   |  _expected `u64`, found `()`
+   | |
+13 | |     impl Api<Block> for MockApi {
+14 | |         fn test(self, data: u64) {}
+15 | |
+16 | |         fn test2(&mut self, data: u64) {}
+17 | |     }
+18 | | }
+   | |_- in this macro invocation
+   |
+   = note: expected fn pointer `fn(&MockApi, &sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::BlockId<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u64, sp_runtime::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::ExecutionContext, std::option::Option<u64>, std::vec::Vec<_>) -> std::result::Result<_, _>`
+              found fn pointer `fn(&MockApi, &sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::BlockId<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u64, sp_runtime::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::ExecutionContext, std::option::Option<()>, std::vec::Vec<_>) -> std::result::Result<_, _>`
+
+error[E0053]: method `Api_test2_runtime_api_impl` has an incompatible type for trait
+  --> $DIR/mock_only_self_reference.rs:12:1
+   |
+3  | / sp_api::decl_runtime_apis! {
+4  | |     pub trait Api {
+5  | |         fn test(data: u64);
+6  | |         fn test2(data: u64);
+7  | |     }
+8  | | }
+   | |_- type in trait
+...
+12 |   sp_api::mock_impl_runtime_apis! {
+   |   -^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |   |
+   |  _expected `u64`, found `()`
+   | |
+13 | |     impl Api<Block> for MockApi {
+14 | |         fn test(self, data: u64) {}
+15 | |
+16 | |         fn test2(&mut self, data: u64) {}
+17 | |     }
+18 | | }
+   | |_- in this macro invocation
+   |
+   = note: expected fn pointer `fn(&MockApi, &sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::BlockId<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u64, sp_runtime::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::ExecutionContext, std::option::Option<u64>, std::vec::Vec<_>) -> std::result::Result<_, _>`
+              found fn pointer `fn(&MockApi, &sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::BlockId<sp_runtime::generic::block::Block<sp_runtime::generic::header::Header<u64, sp_runtime::traits::BlakeTwo256>, substrate_test_runtime::Extrinsic>>, sp_api_hidden_includes_DECL_RUNTIME_APIS::sp_api::ExecutionContext, std::option::Option<()>, std::vec::Vec<_>) -> std::result::Result<_, _>`