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