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 use rustc_ast as ast;
   5 use rustc_ast::attr;
   6 use rustc_ast::ptr::P;
   7 use rustc_ast_pretty::pprust;
   8 use rustc_errors::Applicability;
   9 use rustc_expand::base::*;
  10 use rustc_session::Session;
  11 use rustc_span::symbol::{sym, Ident, Symbol};
  12 use rustc_span::Span;
  13 use std::iter;
  14 use thin_vec::thin_vec;
  15
  16 // #[test_case] is used by custom test authors to mark tests
  17 // When building for test, it needs to make the item public and gensym the name
  18 // Otherwise, we'll omit the item. This behavior means that any item annotated
  19 // with #[test_case] is never addressable.
  20 //
  21 // We mark item with an inert attribute "rustc_test_marker" which the test generation
  22 // logic will pick up on.
  23 pub fn expand_test_case(
  24     ecx: &mut ExtCtxt<'_>,
  25     attr_sp: Span,
  26     meta_item: &ast::MetaItem,
  27     anno_item: Annotatable,
  28 ) -> Vec<Annotatable> {
  29     check_builtin_macro_attribute(ecx, meta_item, sym::test_case);
  30     warn_on_duplicate_attribute(&ecx, &anno_item, sym::test_case);
  31
  32     if !ecx.ecfg.should_test {
  33         return vec![];
  34     }
  35
  36     let sp = ecx.with_def_site_ctxt(attr_sp);
  37     let mut item = anno_item.expect_item();
  38     item = item.map(|mut item| {
  39         let test_path_symbol = Symbol::intern(&item_path(
  40             // skip the name of the root module
  41             &ecx.current_expansion.module.mod_path[1..],
  42             &item.ident,
  43         ));
  44         item.vis = ast::Visibility {
  45             span: item.vis.span,
  46             kind: ast::VisibilityKind::Public,
  47             tokens: None,
  48         };
  49         item.ident.span = item.ident.span.with_ctxt(sp.ctxt());
  50         item.attrs.push(ecx.attribute(attr::mk_name_value_item_str(
  51             Ident::new(sym::rustc_test_marker, sp),
  52             test_path_symbol,
  53             sp,
  54         )));
  55         item
  56     });
  57
  58     return vec![Annotatable::Item(item)];
  59 }
  60
  61 pub fn expand_test(
  62     cx: &mut ExtCtxt<'_>,
  63     attr_sp: Span,
  64     meta_item: &ast::MetaItem,
  65     item: Annotatable,
  66 ) -> Vec<Annotatable> {
  67     check_builtin_macro_attribute(cx, meta_item, sym::test);
  68     warn_on_duplicate_attribute(&cx, &item, sym::test);
  69     expand_test_or_bench(cx, attr_sp, item, false)
  70 }
  71
  72 pub fn expand_bench(
  73     cx: &mut ExtCtxt<'_>,
  74     attr_sp: Span,
  75     meta_item: &ast::MetaItem,
  76     item: Annotatable,
  77 ) -> Vec<Annotatable> {
  78     check_builtin_macro_attribute(cx, meta_item, sym::bench);
  79     warn_on_duplicate_attribute(&cx, &item, sym::bench);
  80     expand_test_or_bench(cx, attr_sp, item, true)
  81 }
  82
  83 pub fn expand_test_or_bench(
  84     cx: &mut ExtCtxt<'_>,
  85     attr_sp: Span,
  86     item: Annotatable,
  87     is_bench: bool,
  88 ) -> Vec<Annotatable> {
  89     // If we're not in test configuration, remove the annotated item
  90     if !cx.ecfg.should_test {
  91         return vec![];
  92     }
  93
  94     let (item, is_stmt) = match item {
  95         Annotatable::Item(i) => (i, false),
  96         Annotatable::Stmt(stmt) if matches!(stmt.kind, ast::StmtKind::Item(_)) => {
  97             // FIXME: Use an 'if let' guard once they are implemented
  98             if let ast::StmtKind::Item(i) = stmt.into_inner().kind {
  99                 (i, true)
 100             } else {
 101                 unreachable!()
 102             }
 103         }
 104         other => {
 105             cx.struct_span_err(
 106                 other.span(),
 107                 "`#[test]` attribute is only allowed on non associated functions",
 108             )
 109             .emit();
 110             return vec![other];
 111         }
 112     };
 113
 114     // Note: non-associated fn items are already handled by `expand_test_or_bench`
 115     if !matches!(item.kind, ast::ItemKind::Fn(_)) {
 116         let diag = &cx.sess.parse_sess.span_diagnostic;
 117         let msg = "the `#[test]` attribute may only be used on a non-associated function";
 118         let mut err = match item.kind {
 119             // These were a warning before #92959 and need to continue being that to avoid breaking
 120             // stable user code (#94508).
 121             ast::ItemKind::MacCall(_) => diag.struct_span_warn(attr_sp, msg),
 122             // `.forget_guarantee()` needed to get these two arms to match types. Because of how
 123             // locally close the `.emit()` call is I'm comfortable with it, but if it can be
 124             // reworked in the future to not need it, it'd be nice.
 125             _ => diag.struct_span_err(attr_sp, msg).forget_guarantee(),
 126         };
 127         err.span_label(attr_sp, "the `#[test]` macro causes a function to be run on a test and has no effect on non-functions")
 128             .span_label(item.span, format!("expected a non-associated function, found {} {}", item.kind.article(), item.kind.descr()))
 129             .span_suggestion(attr_sp, "replace with conditional compilation to make the item only exist when tests are being run", "#[cfg(test)]", Applicability::MaybeIncorrect)
 130             .emit();
 131
 132         return vec![Annotatable::Item(item)];
 133     }
 134
 135     // has_*_signature will report any errors in the type so compilation
 136     // will fail. We shouldn't try to expand in this case because the errors
 137     // would be spurious.
 138     if (!is_bench && !has_test_signature(cx, &item))
 139         || (is_bench && !has_bench_signature(cx, &item))
 140     {
 141         return vec![Annotatable::Item(item)];
 142     }
 143
 144     let (sp, attr_sp) = (cx.with_def_site_ctxt(item.span), cx.with_def_site_ctxt(attr_sp));
 145
 146     let test_id = Ident::new(sym::test, attr_sp);
 147
 148     // creates test::$name
 149     let test_path = |name| cx.path(sp, vec![test_id, Ident::from_str_and_span(name, sp)]);
 150
 151     // creates test::ShouldPanic::$name
 152     let should_panic_path = |name| {
 153         cx.path(
 154             sp,
 155             vec![
 156                 test_id,
 157                 Ident::from_str_and_span("ShouldPanic", sp),
 158                 Ident::from_str_and_span(name, sp),
 159             ],
 160         )
 161     };
 162
 163     // creates test::TestType::$name
 164     let test_type_path = |name| {
 165         cx.path(
 166             sp,
 167             vec![
 168                 test_id,
 169                 Ident::from_str_and_span("TestType", sp),
 170                 Ident::from_str_and_span(name, sp),
 171             ],
 172         )
 173     };
 174
 175     // creates $name: $expr
 176     let field = |name, expr| cx.field_imm(sp, Ident::from_str_and_span(name, sp), expr);
 177
 178     let test_fn = if is_bench {
 179         // A simple ident for a lambda
 180         let b = Ident::from_str_and_span("b", attr_sp);
 181
 182         cx.expr_call(
 183             sp,
 184             cx.expr_path(test_path("StaticBenchFn")),
 185             vec![
 186                 // |b| self::test::assert_test_result(
 187                 cx.lambda1(
 188                     sp,
 189                     cx.expr_call(
 190                         sp,
 191                         cx.expr_path(test_path("assert_test_result")),
 192                         vec![
 193                             // super::$test_fn(b)
 194                             cx.expr_call(
 195                                 sp,
 196                                 cx.expr_path(cx.path(sp, vec![item.ident])),
 197                                 vec![cx.expr_ident(sp, b)],
 198                             ),
 199                         ],
 200                     ),
 201                     b,
 202                 ), // )
 203             ],
 204         )
 205     } else {
 206         cx.expr_call(
 207             sp,
 208             cx.expr_path(test_path("StaticTestFn")),
 209             vec![
 210                 // || {
 211                 cx.lambda0(
 212                     sp,
 213                     // test::assert_test_result(
 214                     cx.expr_call(
 215                         sp,
 216                         cx.expr_path(test_path("assert_test_result")),
 217                         vec![
 218                             // $test_fn()
 219                             cx.expr_call(sp, cx.expr_path(cx.path(sp, vec![item.ident])), vec![]), // )
 220                         ],
 221                     ), // }
 222                 ), // )
 223             ],
 224         )
 225     };
 226
 227     let test_path_symbol = Symbol::intern(&item_path(
 228         // skip the name of the root module
 229         &cx.current_expansion.module.mod_path[1..],
 230         &item.ident,
 231     ));
 232
 233     let mut test_const = cx.item(
 234         sp,
 235         Ident::new(item.ident.name, sp),
 236         thin_vec![
 237             // #[cfg(test)]
 238             cx.attribute(attr::mk_list_item(
 239                 Ident::new(sym::cfg, attr_sp),
 240                 vec![attr::mk_nested_word_item(Ident::new(sym::test, attr_sp))],
 241             )),
 242             // #[rustc_test_marker = "test_case_sort_key"]
 243             cx.attribute(attr::mk_name_value_item_str(
 244                 Ident::new(sym::rustc_test_marker, attr_sp),
 245                 test_path_symbol,
 246                 attr_sp,
 247             )),
 248         ]
 249         .into(),
 250         // const $ident: test::TestDescAndFn =
 251         ast::ItemKind::Const(
 252             ast::Defaultness::Final,
 253             cx.ty(sp, ast::TyKind::Path(None, test_path("TestDescAndFn"))),
 254             // test::TestDescAndFn {
 255             Some(
 256                 cx.expr_struct(
 257                     sp,
 258                     test_path("TestDescAndFn"),
 259                     vec![
 260                         // desc: test::TestDesc {
 261                         field(
 262                             "desc",
 263                             cx.expr_struct(
 264                                 sp,
 265                                 test_path("TestDesc"),
 266                                 vec![
 267                                     // name: "path::to::test"
 268                                     field(
 269                                         "name",
 270                                         cx.expr_call(
 271                                             sp,
 272                                             cx.expr_path(test_path("StaticTestName")),
 273                                             vec![cx.expr_str(sp, test_path_symbol)],
 274                                         ),
 275                                     ),
 276                                     // ignore: true | false
 277                                     field(
 278                                         "ignore",
 279                                         cx.expr_bool(sp, should_ignore(&cx.sess, &item)),
 280                                     ),
 281                                     // ignore_message: Some("...") | None
 282                                     field(
 283                                         "ignore_message",
 284                                         if let Some(msg) = should_ignore_message(cx, &item) {
 285                                             cx.expr_some(sp, cx.expr_str(sp, msg))
 286                                         } else {
 287                                             cx.expr_none(sp)
 288                                         },
 289                                     ),
 290                                     // compile_fail: true | false
 291                                     field("compile_fail", cx.expr_bool(sp, false)),
 292                                     // no_run: true | false
 293                                     field("no_run", cx.expr_bool(sp, false)),
 294                                     // should_panic: ...
 295                                     field(
 296                                         "should_panic",
 297                                         match should_panic(cx, &item) {
 298                                             // test::ShouldPanic::No
 299                                             ShouldPanic::No => {
 300                                                 cx.expr_path(should_panic_path("No"))
 301                                             }
 302                                             // test::ShouldPanic::Yes
 303                                             ShouldPanic::Yes(None) => {
 304                                                 cx.expr_path(should_panic_path("Yes"))
 305                                             }
 306                                             // test::ShouldPanic::YesWithMessage("...")
 307                                             ShouldPanic::Yes(Some(sym)) => cx.expr_call(
 308                                                 sp,
 309                                                 cx.expr_path(should_panic_path("YesWithMessage")),
 310                                                 vec![cx.expr_str(sp, sym)],
 311                                             ),
 312                                         },
 313                                     ),
 314                                     // test_type: ...
 315                                     field(
 316                                         "test_type",
 317                                         match test_type(cx) {
 318                                             // test::TestType::UnitTest
 319                                             TestType::UnitTest => {
 320                                                 cx.expr_path(test_type_path("UnitTest"))
 321                                             }
 322                                             // test::TestType::IntegrationTest
 323                                             TestType::IntegrationTest => {
 324                                                 cx.expr_path(test_type_path("IntegrationTest"))
 325                                             }
 326                                             // test::TestPath::Unknown
 327                                             TestType::Unknown => {
 328                                                 cx.expr_path(test_type_path("Unknown"))
 329                                             }
 330                                         },
 331                                     ),
 332                                     // },
 333                                 ],
 334                             ),
 335                         ),
 336                         // testfn: test::StaticTestFn(...) | test::StaticBenchFn(...)
 337                         field("testfn", test_fn), // }
 338                     ],
 339                 ), // }
 340             ),
 341         ),
 342     );
 343     test_const = test_const.map(|mut tc| {
 344         tc.vis.kind = ast::VisibilityKind::Public;
 345         tc
 346     });
 347
 348     // extern crate test
 349     let test_extern = cx.item(sp, test_id, ast::AttrVec::new(), ast::ItemKind::ExternCrate(None));
 350
 351     debug!("synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
 352
 353     if is_stmt {
 354         vec![
 355             // Access to libtest under a hygienic name
 356             Annotatable::Stmt(P(cx.stmt_item(sp, test_extern))),
 357             // The generated test case
 358             Annotatable::Stmt(P(cx.stmt_item(sp, test_const))),
 359             // The original item
 360             Annotatable::Stmt(P(cx.stmt_item(sp, item))),
 361         ]
 362     } else {
 363         vec![
 364             // Access to libtest under a hygienic name
 365             Annotatable::Item(test_extern),
 366             // The generated test case
 367             Annotatable::Item(test_const),
 368             // The original item
 369             Annotatable::Item(item),
 370         ]
 371     }
 372 }
 373
 374 fn item_path(mod_path: &[Ident], item_ident: &Ident) -> String {
 375     mod_path
 376         .iter()
 377         .chain(iter::once(item_ident))
 378         .map(|x| x.to_string())
 379         .collect::<Vec<String>>()
 380         .join("::")
 381 }
 382
 383 enum ShouldPanic {
 384     No,
 385     Yes(Option<Symbol>),
 386 }
 387
 388 fn should_ignore(sess: &Session, i: &ast::Item) -> bool {
 389     sess.contains_name(&i.attrs, sym::ignore)
 390 }
 391
 392 fn should_ignore_message(cx: &ExtCtxt<'_>, i: &ast::Item) -> Option<Symbol> {
 393     match cx.sess.find_by_name(&i.attrs, sym::ignore) {
 394         Some(attr) => {
 395             match attr.meta_item_list() {
 396                 // Handle #[ignore(bar = "foo")]
 397                 Some(_) => None,
 398                 // Handle #[ignore] and #[ignore = "message"]
 399                 None => attr.value_str(),
 400             }
 401         }
 402         None => None,
 403     }
 404 }
 405
 406 fn should_panic(cx: &ExtCtxt<'_>, i: &ast::Item) -> ShouldPanic {
 407     match cx.sess.find_by_name(&i.attrs, sym::should_panic) {
 408         Some(attr) => {
 409             let sd = &cx.sess.parse_sess.span_diagnostic;
 410
 411             match attr.meta_item_list() {
 412                 // Handle #[should_panic(expected = "foo")]
 413                 Some(list) => {
 414                     let msg = list
 415                         .iter()
 416                         .find(|mi| mi.has_name(sym::expected))
 417                         .and_then(|mi| mi.meta_item())
 418                         .and_then(|mi| mi.value_str());
 419                     if list.len() != 1 || msg.is_none() {
 420                         sd.struct_span_warn(
 421                             attr.span,
 422                             "argument must be of the form: \
 423                              `expected = \"error message\"`",
 424                         )
 425                         .note(
 426                             "errors in this attribute were erroneously \
 427                                 allowed and will become a hard error in a \
 428                                 future release",
 429                         )
 430                         .emit();
 431                         ShouldPanic::Yes(None)
 432                     } else {
 433                         ShouldPanic::Yes(msg)
 434                     }
 435                 }
 436                 // Handle #[should_panic] and #[should_panic = "expected"]
 437                 None => ShouldPanic::Yes(attr.value_str()),
 438             }
 439         }
 440         None => ShouldPanic::No,
 441     }
 442 }
 443
 444 enum TestType {
 445     UnitTest,
 446     IntegrationTest,
 447     Unknown,
 448 }
 449
 450 /// Attempts to determine the type of test.
 451 /// Since doctests are created without macro expanding, only possible variants here
 452 /// are `UnitTest`, `IntegrationTest` or `Unknown`.
 453 fn test_type(cx: &ExtCtxt<'_>) -> TestType {
 454     // Root path from context contains the topmost sources directory of the crate.
 455     // I.e., for `project` with sources in `src` and tests in `tests` folders
 456     // (no matter how many nested folders lie inside),
 457     // there will be two different root paths: `/project/src` and `/project/tests`.
 458     let crate_path = cx.root_path.as_path();
 459
 460     if crate_path.ends_with("src") {
 461         // `/src` folder contains unit-tests.
 462         TestType::UnitTest
 463     } else if crate_path.ends_with("tests") {
 464         // `/tests` folder contains integration tests.
 465         TestType::IntegrationTest
 466     } else {
 467         // Crate layout doesn't match expected one, test type is unknown.
 468         TestType::Unknown
 469     }
 470 }
 471
 472 fn has_test_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
 473     let has_should_panic_attr = cx.sess.contains_name(&i.attrs, sym::should_panic);
 474     let sd = &cx.sess.parse_sess.span_diagnostic;
 475     if let ast::ItemKind::Fn(box ast::Fn { ref sig, ref generics, .. }) = i.kind {
 476         if let ast::Unsafe::Yes(span) = sig.header.unsafety {
 477             sd.struct_span_err(i.span, "unsafe functions cannot be used for tests")
 478                 .span_label(span, "`unsafe` because of this")
 479                 .emit();
 480             return false;
 481         }
 482         if let ast::Async::Yes { span, .. } = sig.header.asyncness {
 483             sd.struct_span_err(i.span, "async functions cannot be used for tests")
 484                 .span_label(span, "`async` because of this")
 485                 .emit();
 486             return false;
 487         }
 488
 489         // If the termination trait is active, the compiler will check that the output
 490         // type implements the `Termination` trait as `libtest` enforces that.
 491         let has_output = match sig.decl.output {
 492             ast::FnRetTy::Default(..) => false,
 493             ast::FnRetTy::Ty(ref t) if t.kind.is_unit() => false,
 494             _ => true,
 495         };
 496
 497         if !sig.decl.inputs.is_empty() {
 498             sd.span_err(i.span, "functions used as tests can not have any arguments");
 499             return false;
 500         }
 501
 502         match (has_output, has_should_panic_attr) {
 503             (true, true) => {
 504                 sd.span_err(i.span, "functions using `#[should_panic]` must return `()`");
 505                 false
 506             }
 507             (true, false) => {
 508                 if !generics.params.is_empty() {
 509                     sd.span_err(i.span, "functions used as tests must have signature fn() -> ()");
 510                     false
 511                 } else {
 512                     true
 513                 }
 514             }
 515             (false, _) => true,
 516         }
 517     } else {
 518         // should be unreachable because `is_test_fn_item` should catch all non-fn items
 519         false
 520     }
 521 }
 522
 523 fn has_bench_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
 524     let has_sig = if let ast::ItemKind::Fn(box ast::Fn { ref sig, .. }) = i.kind {
 525         // N.B., inadequate check, but we're running
 526         // well before resolve, can't get too deep.
 527         sig.decl.inputs.len() == 1
 528     } else {
 529         false
 530     };
 531
 532     if !has_sig {
 533         cx.sess.parse_sess.span_diagnostic.span_err(
 534             i.span,
 535             "functions used as benches must have \
 536             signature `fn(&mut Bencher) -> impl Termination`",
 537         );
 538     }
 539
 540     has_sig
 541 }