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