compiler/rustc_builtin_macros/src/test.rs

   1 /// The expansion from a test function to the appropriate test struct for libtest
   2 /// Ideally, this code would be in libtest but for efficiency and error messages it lives here.
   3 use crate::util::{check_builtin_macro_attribute, warn_on_duplicate_attribute};
   4
   5 use rustc_ast as ast;
   6 use rustc_ast::attr;
   7 use rustc_ast::ptr::P;
   8 use rustc_ast_pretty::pprust;
   9 use rustc_errors::Applicability;
  10 use rustc_expand::base::*;
  11 use rustc_session::Session;
  12 use rustc_span::symbol::{sym, Ident, Symbol};
  13 use rustc_span::Span;
  14
  15 use std::iter;
  16
  17 // #[test_case] is used by custom test authors to mark tests
  18 // When building for test, it needs to make the item public and gensym the name
  19 // Otherwise, we'll omit the item. This behavior means that any item annotated
  20 // with #[test_case] is never addressable.
  21 //
  22 // We mark item with an inert attribute "rustc_test_marker" which the test generation
  23 // logic will pick up on.
  24 pub fn expand_test_case(
  25     ecx: &mut ExtCtxt<'_>,
  26     attr_sp: Span,
  27     meta_item: &ast::MetaItem,
  28     anno_item: Annotatable,
  29 ) -> Vec<Annotatable> {
  30     check_builtin_macro_attribute(ecx, meta_item, sym::test_case);
  31     warn_on_duplicate_attribute(&ecx, &anno_item, sym::test_case);
  32
  33     if !ecx.ecfg.should_test {
  34         return vec![];
  35     }
  36
  37     let sp = ecx.with_def_site_ctxt(attr_sp);
  38     let mut item = anno_item.expect_item();
  39     item = item.map(|mut item| {
  40         item.vis = ast::Visibility {
  41             span: item.vis.span,
  42             kind: ast::VisibilityKind::Public,
  43             tokens: None,
  44         };
  45         item.ident.span = item.ident.span.with_ctxt(sp.ctxt());
  46         item.attrs.push(ecx.attribute(ecx.meta_word(sp, sym::rustc_test_marker)));
  47         item
  48     });
  49
  50     return vec![Annotatable::Item(item)];
  51 }
  52
  53 pub fn expand_test(
  54     cx: &mut ExtCtxt<'_>,
  55     attr_sp: Span,
  56     meta_item: &ast::MetaItem,
  57     item: Annotatable,
  58 ) -> Vec<Annotatable> {
  59     check_builtin_macro_attribute(cx, meta_item, sym::test);
  60     warn_on_duplicate_attribute(&cx, &item, sym::test);
  61     expand_test_or_bench(cx, attr_sp, item, false)
  62 }
  63
  64 pub fn expand_bench(
  65     cx: &mut ExtCtxt<'_>,
  66     attr_sp: Span,
  67     meta_item: &ast::MetaItem,
  68     item: Annotatable,
  69 ) -> Vec<Annotatable> {
  70     check_builtin_macro_attribute(cx, meta_item, sym::bench);
  71     warn_on_duplicate_attribute(&cx, &item, sym::bench);
  72     expand_test_or_bench(cx, attr_sp, item, true)
  73 }
  74
  75 pub fn expand_test_or_bench(
  76     cx: &mut ExtCtxt<'_>,
  77     attr_sp: Span,
  78     item: Annotatable,
  79     is_bench: bool,
  80 ) -> Vec<Annotatable> {
  81     // If we're not in test configuration, remove the annotated item
  82     if !cx.ecfg.should_test {
  83         return vec![];
  84     }
  85
  86     let (item, is_stmt) = match item {
  87         Annotatable::Item(i) => (i, false),
  88         Annotatable::Stmt(stmt) if matches!(stmt.kind, ast::StmtKind::Item(_)) => {
  89             // FIXME: Use an 'if let' guard once they are implemented
  90             if let ast::StmtKind::Item(i) = stmt.into_inner().kind {
  91                 (i, true)
  92             } else {
  93                 unreachable!()
  94             }
  95         }
  96         other => {
  97             cx.struct_span_err(
  98                 other.span(),
  99                 "`#[test]` attribute is only allowed on non associated functions",
 100             )
 101             .emit();
 102             return vec![other];
 103         }
 104     };
 105
 106     // Note: non-associated fn items are already handled by `expand_test_or_bench`
 107     if !matches!(item.kind, ast::ItemKind::Fn(_)) {
 108         cx.sess
 109             .parse_sess
 110             .span_diagnostic
 111             .struct_span_err(
 112                 attr_sp,
 113                 "the `#[test]` attribute may only be used on a non-associated function",
 114             )
 115             .note("the `#[test]` macro causes a a function to be run on a test and has no effect on non-functions")
 116             .span_label(item.span, format!("expected a non-associated function, found {} {}", item.kind.article(), item.kind.descr()))
 117             .span_suggestion(attr_sp, "replace with conditional compilation to make the item only exist when tests are being run", String::from("#[cfg(test)]"), Applicability::MaybeIncorrect)
 118             .emit();
 119
 120         return vec![Annotatable::Item(item)];
 121     }
 122
 123     // has_*_signature will report any errors in the type so compilation
 124     // will fail. We shouldn't try to expand in this case because the errors
 125     // would be spurious.
 126     if (!is_bench && !has_test_signature(cx, &item))
 127         || (is_bench && !has_bench_signature(cx, &item))
 128     {
 129         return vec![Annotatable::Item(item)];
 130     }
 131
 132     let (sp, attr_sp) = (cx.with_def_site_ctxt(item.span), cx.with_def_site_ctxt(attr_sp));
 133
 134     let test_id = Ident::new(sym::test, attr_sp);
 135
 136     // creates test::$name
 137     let test_path = |name| cx.path(sp, vec![test_id, Ident::from_str_and_span(name, sp)]);
 138
 139     // creates test::ShouldPanic::$name
 140     let should_panic_path = |name| {
 141         cx.path(
 142             sp,
 143             vec![
 144                 test_id,
 145                 Ident::from_str_and_span("ShouldPanic", sp),
 146                 Ident::from_str_and_span(name, sp),
 147             ],
 148         )
 149     };
 150
 151     // creates test::TestType::$name
 152     let test_type_path = |name| {
 153         cx.path(
 154             sp,
 155             vec![
 156                 test_id,
 157                 Ident::from_str_and_span("TestType", sp),
 158                 Ident::from_str_and_span(name, sp),
 159             ],
 160         )
 161     };
 162
 163     // creates $name: $expr
 164     let field = |name, expr| cx.field_imm(sp, Ident::from_str_and_span(name, sp), expr);
 165
 166     let test_fn = if is_bench {
 167         // A simple ident for a lambda
 168         let b = Ident::from_str_and_span("b", attr_sp);
 169
 170         cx.expr_call(
 171             sp,
 172             cx.expr_path(test_path("StaticBenchFn")),
 173             vec![
 174                 // |b| self::test::assert_test_result(
 175                 cx.lambda1(
 176                     sp,
 177                     cx.expr_call(
 178                         sp,
 179                         cx.expr_path(test_path("assert_test_result")),
 180                         vec![
 181                             // super::$test_fn(b)
 182                             cx.expr_call(
 183                                 sp,
 184                                 cx.expr_path(cx.path(sp, vec![item.ident])),
 185                                 vec![cx.expr_ident(sp, b)],
 186                             ),
 187                         ],
 188                     ),
 189                     b,
 190                 ), // )
 191             ],
 192         )
 193     } else {
 194         cx.expr_call(
 195             sp,
 196             cx.expr_path(test_path("StaticTestFn")),
 197             vec![
 198                 // || {
 199                 cx.lambda0(
 200                     sp,
 201                     // test::assert_test_result(
 202                     cx.expr_call(
 203                         sp,
 204                         cx.expr_path(test_path("assert_test_result")),
 205                         vec![
 206                             // $test_fn()
 207                             cx.expr_call(sp, cx.expr_path(cx.path(sp, vec![item.ident])), vec![]), // )
 208                         ],
 209                     ), // }
 210                 ), // )
 211             ],
 212         )
 213     };
 214
 215     let mut test_const = cx.item(
 216         sp,
 217         Ident::new(item.ident.name, sp),
 218         vec![
 219             // #[cfg(test)]
 220             cx.attribute(attr::mk_list_item(
 221                 Ident::new(sym::cfg, attr_sp),
 222                 vec![attr::mk_nested_word_item(Ident::new(sym::test, attr_sp))],
 223             )),
 224             // #[rustc_test_marker]
 225             cx.attribute(cx.meta_word(attr_sp, sym::rustc_test_marker)),
 226         ],
 227         // const $ident: test::TestDescAndFn =
 228         ast::ItemKind::Const(
 229             ast::Defaultness::Final,
 230             cx.ty(sp, ast::TyKind::Path(None, test_path("TestDescAndFn"))),
 231             // test::TestDescAndFn {
 232             Some(
 233                 cx.expr_struct(
 234                     sp,
 235                     test_path("TestDescAndFn"),
 236                     vec![
 237                         // desc: test::TestDesc {
 238                         field(
 239                             "desc",
 240                             cx.expr_struct(
 241                                 sp,
 242                                 test_path("TestDesc"),
 243                                 vec![
 244                                     // name: "path::to::test"
 245                                     field(
 246                                         "name",
 247                                         cx.expr_call(
 248                                             sp,
 249                                             cx.expr_path(test_path("StaticTestName")),
 250                                             vec![cx.expr_str(
 251                                                 sp,
 252                                                 Symbol::intern(&item_path(
 253                                                     // skip the name of the root module
 254                                                     &cx.current_expansion.module.mod_path[1..],
 255                                                     &item.ident,
 256                                                 )),
 257                                             )],
 258                                         ),
 259                                     ),
 260                                     // ignore: true | false
 261                                     field(
 262                                         "ignore",
 263                                         cx.expr_bool(sp, should_ignore(&cx.sess, &item)),
 264                                     ),
 265                                     // compile_fail: true | false
 266                                     field("compile_fail", cx.expr_bool(sp, false)),
 267                                     // no_run: true | false
 268                                     field("no_run", cx.expr_bool(sp, false)),
 269                                     // should_panic: ...
 270                                     field(
 271                                         "should_panic",
 272                                         match should_panic(cx, &item) {
 273                                             // test::ShouldPanic::No
 274                                             ShouldPanic::No => {
 275                                                 cx.expr_path(should_panic_path("No"))
 276                                             }
 277                                             // test::ShouldPanic::Yes
 278                                             ShouldPanic::Yes(None) => {
 279                                                 cx.expr_path(should_panic_path("Yes"))
 280                                             }
 281                                             // test::ShouldPanic::YesWithMessage("...")
 282                                             ShouldPanic::Yes(Some(sym)) => cx.expr_call(
 283                                                 sp,
 284                                                 cx.expr_path(should_panic_path("YesWithMessage")),
 285                                                 vec![cx.expr_str(sp, sym)],
 286                                             ),
 287                                         },
 288                                     ),
 289                                     // test_type: ...
 290                                     field(
 291                                         "test_type",
 292                                         match test_type(cx) {
 293                                             // test::TestType::UnitTest
 294                                             TestType::UnitTest => {
 295                                                 cx.expr_path(test_type_path("UnitTest"))
 296                                             }
 297                                             // test::TestType::IntegrationTest
 298                                             TestType::IntegrationTest => {
 299                                                 cx.expr_path(test_type_path("IntegrationTest"))
 300                                             }
 301                                             // test::TestPath::Unknown
 302                                             TestType::Unknown => {
 303                                                 cx.expr_path(test_type_path("Unknown"))
 304                                             }
 305                                         },
 306                                     ),
 307                                     // },
 308                                 ],
 309                             ),
 310                         ),
 311                         // testfn: test::StaticTestFn(...) | test::StaticBenchFn(...)
 312                         field("testfn", test_fn), // }
 313                     ],
 314                 ), // }
 315             ),
 316         ),
 317     );
 318     test_const = test_const.map(|mut tc| {
 319         tc.vis.kind = ast::VisibilityKind::Public;
 320         tc
 321     });
 322
 323     // extern crate test
 324     let test_extern = cx.item(sp, test_id, vec![], ast::ItemKind::ExternCrate(None));
 325
 326     tracing::debug!("synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
 327
 328     if is_stmt {
 329         vec![
 330             // Access to libtest under a hygienic name
 331             Annotatable::Stmt(P(cx.stmt_item(sp, test_extern))),
 332             // The generated test case
 333             Annotatable::Stmt(P(cx.stmt_item(sp, test_const))),
 334             // The original item
 335             Annotatable::Stmt(P(cx.stmt_item(sp, item))),
 336         ]
 337     } else {
 338         vec![
 339             // Access to libtest under a hygienic name
 340             Annotatable::Item(test_extern),
 341             // The generated test case
 342             Annotatable::Item(test_const),
 343             // The original item
 344             Annotatable::Item(item),
 345         ]
 346     }
 347 }
 348
 349 fn item_path(mod_path: &[Ident], item_ident: &Ident) -> String {
 350     mod_path
 351         .iter()
 352         .chain(iter::once(item_ident))
 353         .map(|x| x.to_string())
 354         .collect::<Vec<String>>()
 355         .join("::")
 356 }
 357
 358 enum ShouldPanic {
 359     No,
 360     Yes(Option<Symbol>),
 361 }
 362
 363 fn should_ignore(sess: &Session, i: &ast::Item) -> bool {
 364     sess.contains_name(&i.attrs, sym::ignore)
 365 }
 366
 367 fn should_panic(cx: &ExtCtxt<'_>, i: &ast::Item) -> ShouldPanic {
 368     match cx.sess.find_by_name(&i.attrs, sym::should_panic) {
 369         Some(attr) => {
 370             let sd = &cx.sess.parse_sess.span_diagnostic;
 371
 372             match attr.meta_item_list() {
 373                 // Handle #[should_panic(expected = "foo")]
 374                 Some(list) => {
 375                     let msg = list
 376                         .iter()
 377                         .find(|mi| mi.has_name(sym::expected))
 378                         .and_then(|mi| mi.meta_item())
 379                         .and_then(|mi| mi.value_str());
 380                     if list.len() != 1 || msg.is_none() {
 381                         sd.struct_span_warn(
 382                             attr.span,
 383                             "argument must be of the form: \
 384                              `expected = \"error message\"`",
 385                         )
 386                         .note(
 387                             "errors in this attribute were erroneously \
 388                                 allowed and will become a hard error in a \
 389                                 future release",
 390                         )
 391                         .emit();
 392                         ShouldPanic::Yes(None)
 393                     } else {
 394                         ShouldPanic::Yes(msg)
 395                     }
 396                 }
 397                 // Handle #[should_panic] and #[should_panic = "expected"]
 398                 None => ShouldPanic::Yes(attr.value_str()),
 399             }
 400         }
 401         None => ShouldPanic::No,
 402     }
 403 }
 404
 405 enum TestType {
 406     UnitTest,
 407     IntegrationTest,
 408     Unknown,
 409 }
 410
 411 /// Attempts to determine the type of test.
 412 /// Since doctests are created without macro expanding, only possible variants here
 413 /// are `UnitTest`, `IntegrationTest` or `Unknown`.
 414 fn test_type(cx: &ExtCtxt<'_>) -> TestType {
 415     // Root path from context contains the topmost sources directory of the crate.
 416     // I.e., for `project` with sources in `src` and tests in `tests` folders
 417     // (no matter how many nested folders lie inside),
 418     // there will be two different root paths: `/project/src` and `/project/tests`.
 419     let crate_path = cx.root_path.as_path();
 420
 421     if crate_path.ends_with("src") {
 422         // `/src` folder contains unit-tests.
 423         TestType::UnitTest
 424     } else if crate_path.ends_with("tests") {
 425         // `/tests` folder contains integration tests.
 426         TestType::IntegrationTest
 427     } else {
 428         // Crate layout doesn't match expected one, test type is unknown.
 429         TestType::Unknown
 430     }
 431 }
 432
 433 fn has_test_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
 434     let has_should_panic_attr = cx.sess.contains_name(&i.attrs, sym::should_panic);
 435     let sd = &cx.sess.parse_sess.span_diagnostic;
 436     if let ast::ItemKind::Fn(box ast::Fn { ref sig, ref generics, .. }) = i.kind {
 437         if let ast::Unsafe::Yes(span) = sig.header.unsafety {
 438             sd.struct_span_err(i.span, "unsafe functions cannot be used for tests")
 439                 .span_label(span, "`unsafe` because of this")
 440                 .emit();
 441             return false;
 442         }
 443         if let ast::Async::Yes { span, .. } = sig.header.asyncness {
 444             sd.struct_span_err(i.span, "async functions cannot be used for tests")
 445                 .span_label(span, "`async` because of this")
 446                 .emit();
 447             return false;
 448         }
 449
 450         // If the termination trait is active, the compiler will check that the output
 451         // type implements the `Termination` trait as `libtest` enforces that.
 452         let has_output = match sig.decl.output {
 453             ast::FnRetTy::Default(..) => false,
 454             ast::FnRetTy::Ty(ref t) if t.kind.is_unit() => false,
 455             _ => true,
 456         };
 457
 458         if !sig.decl.inputs.is_empty() {
 459             sd.span_err(i.span, "functions used as tests can not have any arguments");
 460             return false;
 461         }
 462
 463         match (has_output, has_should_panic_attr) {
 464             (true, true) => {
 465                 sd.span_err(i.span, "functions using `#[should_panic]` must return `()`");
 466                 false
 467             }
 468             (true, false) => {
 469                 if !generics.params.is_empty() {
 470                     sd.span_err(i.span, "functions used as tests must have signature fn() -> ()");
 471                     false
 472                 } else {
 473                     true
 474                 }
 475             }
 476             (false, _) => true,
 477         }
 478     } else {
 479         // should be unreachable because `is_test_fn_item` should catch all non-fn items
 480         false
 481     }
 482 }
 483
 484 fn has_bench_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
 485     let has_sig = if let ast::ItemKind::Fn(box ast::Fn { ref sig, .. }) = i.kind {
 486         // N.B., inadequate check, but we're running
 487         // well before resolve, can't get too deep.
 488         sig.decl.inputs.len() == 1
 489     } else {
 490         false
 491     };
 492
 493     if !has_sig {
 494         cx.sess.parse_sess.span_diagnostic.span_err(
 495             i.span,
 496             "functions used as benches must have \
 497             signature `fn(&mut Bencher) -> impl Termination`",
 498         );
 499     }
 500
 501     has_sig
 502 }