Add UI tests

Signed-off-by: Oliver Tale-Yazdi <[email protected]>

.gitignore

@@ -1,3 +1,5 @@
 /target/
+**/target
+
 Cargo.lock
 **/*.rs.bk

README.md

@@ -24,6 +24,7 @@ Building a warning is easy with the builder pattern.
 
 ```rust
 use proc_macro_warning::Warning;
+
 let warning = Warning::new_deprecated("my_macro")
 	.old("my_macro()")
 	.new("my_macro::new()")
@@ -35,6 +36,8 @@ let warning = Warning::new_deprecated("my_macro")
 let tokens = quote::quote!(#warning);
 ```
 
+This works in derive-macros, but you **must** put in a span, otherwise it will not show up in the compile output.  
+
 ## Used In 
 
 Substrate (since [#13798](https://github.com/paritytech/substrate/pull/13798)) uses this to emit warnings for its FRAME eDSL on deprecated behaviour.
@@ -69,13 +72,12 @@ warning: use of deprecated constant `pallet::warnings::ConstantWeight_0::_w`:
      |                          
 ```
 
-
 ## License
 
 Licensed under either of at your own choice:
 
-* GNU GENERAL PUBLIC LICENSE, Version 3 ([LICENSE-GPL3](./LICENSE-GPL3) or https://www.gnu.org/licenses/gpl-3.0.txt)
-* Apache License, Version 2.0 ([LICENSE-APACHE2](/LICENSE-APACHE2) or https://www.apache.org/licenses/LICENSE-2.0.txt).
+* GNU GENERAL PUBLIC LICENSE, Version 3 ([LICENSE-GPL3](./LICENSE-GPL3) or [gnu.org](https://www.gnu.org/licenses/gpl-3.0.txt>))
+* Apache License, Version 2.0 ([LICENSE-APACHE2](/LICENSE-APACHE2) or [apache.org](https://www.apache.org/licenses/LICENSE-2.0.txt>)).
 
 ### Contribution
 

src/lib.rs

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: (GPL-3.0 or Apache-2.0)
  */
 
-//! Emit warnings from inside proc macros.
+#![doc = include_str!("../README.md")]
 
 use core::ops::Deref;
 use proc_macro2::Span;

tests/Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+members = [
+	"derive",
+	"ui"
+]

tests/derive/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "derive"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro-warning = { path = "../../" }
+quote = "1.0.26"
+syn = "2.0.15"

tests/derive/src/lib.rs

@@ -0,0 +1,26 @@
+use proc_macro::TokenStream;
+use syn::spanned::Spanned;
+
+#[proc_macro_derive(Deprecated)]
+pub fn deprecated(input: TokenStream) -> TokenStream {
+    impl_dep(input, true)
+}
+
+#[proc_macro_derive(DeprecatedNoSpan)]
+pub fn deprecated2(input: TokenStream) -> TokenStream {
+    impl_dep(input, false)
+}
+
+fn impl_dep(input: TokenStream, span: bool) -> TokenStream {
+    let input = syn::parse_macro_input!(input as syn::DeriveInput);
+
+    let warning = proc_macro_warning::Warning::new_deprecated("test")
+        .old("foo").new("bar");
+    let warning = if span {
+        warning.span(input.span())
+    } else {
+        warning
+    }.build();
+
+    quote::quote!{ #warning }.into()
+}

tests/ui/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ui"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dev-dependencies]
+trybuild = "1.0.80"
+derive = { path = "../derive" }

tests/ui/src/lib.rs

@@ -0,0 +1,17 @@
+#[test]
+#[cfg(test)]
+fn ui_warm() {
+	std::env::set_var("RUSTFLAGS", "--deny warnings");
+	let t = trybuild::TestCases::new();
+
+	t.compile_fail("src/warn/*.rs");
+}
+
+#[test]
+#[cfg(test)]
+fn ui_no_warn() {
+	std::env::set_var("RUSTFLAGS", "--deny warnings");
+	let t = trybuild::TestCases::new();
+
+	t.pass("src/no-warn/*.rs");
+}

tests/ui/src/no-warn/derive_no_span.rs

@@ -0,0 +1,10 @@
+//! Without a span no warning will be printed.
+
+#[derive(derive::DeprecatedNoSpan)]
+struct Test {
+
+}
+
+fn main() {
+    let _ = Test { };
+}

tests/ui/src/warn/derive_basic.rs

@@ -0,0 +1,8 @@
+#[derive(derive::Deprecated)]
+struct Test {
+
+}
+
+fn main() {
+    let _ = Test { };
+}

tests/ui/src/warn/derive_basic.stderr

@@ -0,0 +1,11 @@
+error: use of deprecated constant `test::_w`:
+               It is deprecated to foo.
+               Please instead bar.
+ --> src/warn/derive_basic.rs:2:1
+  |
+2 | / struct Test {
+3 | |
+4 | | }
+  | |_^
+  |
+  = note: `-D deprecated` implied by `-D warnings`