1use proc_macro::TokenStream;
2use quote::{format_ident, quote};
3use std::mem;
4use syn::{
5 parse_macro_input, parse_quote, spanned::Spanned as _, AttributeArgs, FnArg, ItemFn, Lit, Meta,
6 NestedMeta, Type,
7};
8
9#[proc_macro_attribute]
10pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
11 let mut namespace = format_ident!("gpui");
12
13 let args = syn::parse_macro_input!(args as AttributeArgs);
14 let mut max_retries = 0;
15 let mut num_iterations = 1;
16 let mut starting_seed = 0;
17
18 for arg in args {
19 match arg {
20 NestedMeta::Meta(Meta::Path(name))
21 if name.get_ident().map_or(false, |n| n == "self") =>
22 {
23 namespace = format_ident!("crate");
24 }
25 NestedMeta::Meta(Meta::NameValue(meta)) => {
26 let key_name = meta.path.get_ident().map(|i| i.to_string());
27 let result = (|| {
28 match key_name.as_ref().map(String::as_str) {
29 Some("retries") => max_retries = parse_int(&meta.lit)?,
30 Some("iterations") => num_iterations = parse_int(&meta.lit)?,
31 Some("seed") => starting_seed = parse_int(&meta.lit)?,
32 _ => {
33 return Err(TokenStream::from(
34 syn::Error::new(meta.path.span(), "invalid argument")
35 .into_compile_error(),
36 ))
37 }
38 }
39 Ok(())
40 })();
41
42 if let Err(tokens) = result {
43 return tokens;
44 }
45 }
46 other => {
47 return TokenStream::from(
48 syn::Error::new_spanned(other, "invalid argument").into_compile_error(),
49 )
50 }
51 }
52 }
53
54 let mut inner_fn = parse_macro_input!(function as ItemFn);
55 if max_retries > 0 && num_iterations > 1 {
56 return TokenStream::from(
57 syn::Error::new_spanned(inner_fn, "retries and randomized iterations can't be mixed")
58 .into_compile_error(),
59 );
60 }
61 let inner_fn_attributes = mem::take(&mut inner_fn.attrs);
62 let inner_fn_name = format_ident!("_{}", inner_fn.sig.ident);
63 let outer_fn_name = mem::replace(&mut inner_fn.sig.ident, inner_fn_name.clone());
64
65 let mut outer_fn: ItemFn = if inner_fn.sig.asyncness.is_some() {
66 // Pass to the test function the number of app contexts that it needs,
67 // based on its parameter list.
68 let mut inner_fn_args = proc_macro2::TokenStream::new();
69 for (ix, arg) in inner_fn.sig.inputs.iter().enumerate() {
70 if let FnArg::Typed(arg) = arg {
71 if let Type::Path(ty) = &*arg.ty {
72 let last_segment = ty.path.segments.last();
73 match last_segment.map(|s| s.ident.to_string()).as_deref() {
74 Some("TestAppContext") => {
75 let first_entity_id = ix * 100_000;
76 inner_fn_args.extend(quote!(
77 #namespace::TestAppContext::new(
78 foreground_platform.clone(),
79 cx.platform().clone(),
80 deterministic.build_foreground(#ix),
81 deterministic.build_background(),
82 cx.font_cache().clone(),
83 #first_entity_id,
84 ),
85 ));
86 }
87 Some("StdRng") => {
88 inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed)));
89 }
90 _ => {
91 return TokenStream::from(
92 syn::Error::new_spanned(arg, "invalid argument")
93 .into_compile_error(),
94 )
95 }
96 }
97 } else {
98 return TokenStream::from(
99 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
100 );
101 }
102 } else {
103 return TokenStream::from(
104 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
105 );
106 }
107 }
108
109 parse_quote! {
110 #[test]
111 fn #outer_fn_name() {
112 #inner_fn
113
114 #namespace::test::run_test(
115 #num_iterations as u64,
116 #starting_seed as u64,
117 #max_retries,
118 &mut |cx, foreground_platform, deterministic, seed| cx.foreground().run(#inner_fn_name(#inner_fn_args))
119 );
120 }
121 }
122 } else {
123 let mut inner_fn_args = proc_macro2::TokenStream::new();
124 for arg in inner_fn.sig.inputs.iter() {
125 if let FnArg::Typed(arg) = arg {
126 if let Type::Path(ty) = &*arg.ty {
127 let last_segment = ty.path.segments.last();
128 if let Some("StdRng") = last_segment.map(|s| s.ident.to_string()).as_deref() {
129 inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(seed),));
130 }
131 } else {
132 inner_fn_args.extend(quote!(cx,));
133 }
134 } else {
135 return TokenStream::from(
136 syn::Error::new_spanned(arg, "invalid argument").into_compile_error(),
137 );
138 }
139 }
140
141 parse_quote! {
142 #[test]
143 fn #outer_fn_name() {
144 #inner_fn
145
146 #namespace::test::run_test(
147 #num_iterations as u64,
148 #starting_seed as u64,
149 #max_retries,
150 &mut |cx, _, _, seed| #inner_fn_name(#inner_fn_args)
151 );
152 }
153 }
154 };
155 outer_fn.attrs.extend(inner_fn_attributes);
156
157 TokenStream::from(quote!(#outer_fn))
158}
159
160fn parse_int(literal: &Lit) -> Result<usize, TokenStream> {
161 let result = if let Lit::Int(int) = &literal {
162 int.base10_parse()
163 } else {
164 Err(syn::Error::new(literal.span(), "must be an integer"))
165 };
166
167 result.map_err(|err| TokenStream::from(err.into_compile_error()))
168}