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