1 // Code that generates a test runner to run all the tests in a crate
4 use rustc_ast::entry::EntryPointType;
5 use rustc_ast::mut_visit::{ExpectOne, *};
7 use rustc_ast::{attr, ModKind};
8 use rustc_expand::base::{ExtCtxt, ResolverExpand};
9 use rustc_expand::expand::{AstFragment, ExpansionConfig};
10 use rustc_feature::Features;
11 use rustc_session::Session;
12 use rustc_span::hygiene::{AstPass, SyntaxContext, Transparency};
13 use rustc_span::symbol::{sym, Ident, Symbol};
14 use rustc_span::{Span, DUMMY_SP};
15 use rustc_target::spec::PanicStrategy;
16 use smallvec::{smallvec, SmallVec};
28 panic_strategy: PanicStrategy,
30 test_cases: Vec<Test>,
31 reexport_test_harness_main: Option<Symbol>,
32 test_runner: Option<ast::Path>,
35 // Traverse the crate, collecting all the test functions, eliding any
36 // existing main functions, and synthesizing a main test harness
37 pub fn inject(sess: &Session, resolver: &mut dyn ResolverExpand, krate: &mut ast::Crate) {
38 let span_diagnostic = sess.diagnostic();
39 let panic_strategy = sess.panic_strategy();
40 let platform_panic_strategy = sess.target.panic_strategy;
42 // Check for #![reexport_test_harness_main = "some_name"] which gives the
43 // main test function the name `some_name` without hygiene. This needs to be
44 // unconditional, so that the attribute is still marked as used in
46 let reexport_test_harness_main =
47 sess.first_attr_value_str_by_name(&krate.attrs, sym::reexport_test_harness_main);
49 // Do this here so that the test_runner crate attribute gets marked as used
50 // even in non-test builds
51 let test_runner = get_test_runner(sess, span_diagnostic, &krate);
54 let panic_strategy = match (panic_strategy, sess.opts.debugging_opts.panic_abort_tests) {
55 (PanicStrategy::Abort, true) => PanicStrategy::Abort,
56 (PanicStrategy::Abort, false) => {
57 if panic_strategy == platform_panic_strategy {
58 // Silently allow compiling with panic=abort on these platforms,
59 // but with old behavior (abort if a test fails).
62 "building tests with panic=abort is not supported \
63 without `-Zpanic_abort_tests`",
68 (PanicStrategy::Unwind, _) => PanicStrategy::Unwind,
70 generate_test_harness(
73 reexport_test_harness_main,
75 &sess.features_untracked(),
82 struct TestHarnessGenerator<'a> {
87 impl<'a> MutVisitor for TestHarnessGenerator<'a> {
88 fn visit_crate(&mut self, c: &mut ast::Crate) {
89 noop_visit_crate(c, self);
91 // Create a main function to run our tests
92 c.items.push(mk_main(&mut self.cx));
95 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
96 let mut item = i.into_inner();
97 if is_test_case(&self.cx.ext_cx.sess, &item) {
98 debug!("this is a test item");
100 let test = Test { span: item.span, ident: item.ident };
101 self.tests.push(test);
104 // We don't want to recurse into anything other than mods, since
105 // mods or tests inside of functions will break things
106 if let ast::ItemKind::Mod(..) = item.kind {
107 let tests = mem::take(&mut self.tests);
108 noop_visit_item_kind(&mut item.kind, self);
109 let mut tests = mem::replace(&mut self.tests, tests);
111 if !tests.is_empty() {
113 if item.id == ast::DUMMY_NODE_ID { ast::CRATE_NODE_ID } else { item.id };
114 // Create an identifier that will hygienically resolve the test
115 // case name, even in another module.
116 let inner_span = match item.kind {
117 ast::ItemKind::Mod(_, ModKind::Loaded(.., span)) => span,
120 let expn_id = self.cx.ext_cx.resolver.expansion_for_ast_pass(
122 AstPass::TestHarness,
126 for test in &mut tests {
127 // See the comment on `mk_main` for why we're using
128 // `apply_mark` directly.
129 test.ident.span = test.ident.span.apply_mark(expn_id, Transparency::Opaque);
131 self.cx.test_cases.extend(tests);
138 // Beware, this is duplicated in librustc_passes/entry.rs (with
139 // `rustc_hir::Item`), so make sure to keep them in sync.
140 fn entry_point_type(sess: &Session, item: &ast::Item, depth: usize) -> EntryPointType {
142 ast::ItemKind::Fn(..) => {
143 if sess.contains_name(&item.attrs, sym::start) {
144 EntryPointType::Start
145 } else if sess.contains_name(&item.attrs, sym::rustc_main) {
146 EntryPointType::MainAttr
147 } else if item.ident.name == sym::main {
149 // This is a top-level function so can be 'main'
150 EntryPointType::MainNamed
152 EntryPointType::OtherMain
158 _ => EntryPointType::None,
161 /// A folder used to remove any entry points (like fn main) because the harness
162 /// generator will provide its own
163 struct EntryPointCleaner<'a> {
164 // Current depth in the ast
170 impl<'a> MutVisitor for EntryPointCleaner<'a> {
171 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
173 let item = noop_flat_map_item(i, self).expect_one("noop did something");
176 // Remove any #[main] or #[start] from the AST so it doesn't
177 // clash with the one we're going to add, but mark it as
178 // #[allow(dead_code)] to avoid printing warnings.
179 let item = match entry_point_type(self.sess, &item, self.depth) {
180 EntryPointType::MainNamed | EntryPointType::MainAttr | EntryPointType::Start => item
181 .map(|ast::Item { id, ident, attrs, kind, vis, span, tokens }| {
182 let allow_ident = Ident::new(sym::allow, self.def_site);
184 attr::mk_nested_word_item(Ident::new(sym::dead_code, self.def_site));
185 let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
186 let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
190 !self.sess.check_name(attr, sym::rustc_main)
191 && !self.sess.check_name(attr, sym::start)
193 .chain(iter::once(allow_dead_code))
196 ast::Item { id, ident, attrs, kind, vis, span, tokens }
198 EntryPointType::None | EntryPointType::OtherMain => item,
205 /// Crawl over the crate, inserting test reexports and the test main function
206 fn generate_test_harness(
208 resolver: &mut dyn ResolverExpand,
209 reexport_test_harness_main: Option<Symbol>,
210 krate: &mut ast::Crate,
212 panic_strategy: PanicStrategy,
213 test_runner: Option<ast::Path>,
215 let mut econfig = ExpansionConfig::default("test".to_string());
216 econfig.features = Some(features);
218 let ext_cx = ExtCtxt::new(sess, econfig, resolver, None);
220 let expn_id = ext_cx.resolver.expansion_for_ast_pass(
222 AstPass::TestHarness,
223 &[sym::test, sym::rustc_attrs],
226 let def_site = DUMMY_SP.with_def_site_ctxt(expn_id);
228 // Remove the entry points
229 let mut cleaner = EntryPointCleaner { sess, depth: 0, def_site };
230 cleaner.visit_crate(krate);
236 test_cases: Vec::new(),
237 reexport_test_harness_main,
241 TestHarnessGenerator { cx, tests: Vec::new() }.visit_crate(krate);
244 /// Creates a function item for use as the main function of a test build.
245 /// This function will call the `test_runner` as specified by the crate attribute
247 /// By default this expands to
252 /// extern crate test;
253 /// test::test_main_static(&[
261 /// Most of the Ident have the usual def-site hygiene for the AST pass. The
262 /// exception is the `test_const`s. These have a syntax context that has two
263 /// opaque marks: one from the expansion of `test` or `test_case`, and one
264 /// generated in `TestHarnessGenerator::flat_map_item`. When resolving this
265 /// identifier after failing to find a matching identifier in the root module
266 /// we remove the outer mark, and try resolving at its def-site, which will
267 /// then resolve to `test_const`.
269 /// The expansion here can be controlled by two attributes:
271 /// [`TestCtxt::reexport_test_harness_main`] provides a different name for the `main`
272 /// function and [`TestCtxt::test_runner`] provides a path that replaces
273 /// `test::test_main_static`.
274 fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
275 let sp = cx.def_site;
276 let ecx = &cx.ext_cx;
277 let test_id = Ident::new(sym::test, sp);
279 let runner_name = match cx.panic_strategy {
280 PanicStrategy::Unwind => "test_main_static",
281 PanicStrategy::Abort => "test_main_static_abort",
284 // test::test_main_static(...)
285 let mut test_runner = cx
288 .unwrap_or_else(|| ecx.path(sp, vec![test_id, Ident::from_str_and_span(runner_name, sp)]));
290 test_runner.span = sp;
292 let test_main_path_expr = ecx.expr_path(test_runner);
293 let call_test_main = ecx.expr_call(sp, test_main_path_expr, vec![mk_tests_slice(cx, sp)]);
294 let call_test_main = ecx.stmt_expr(call_test_main);
297 let test_extern_stmt =
298 ecx.stmt_item(sp, ecx.item(sp, test_id, vec![], ast::ItemKind::ExternCrate(None)));
301 let main_meta = ecx.meta_word(sp, sym::rustc_main);
302 let main_attr = ecx.attribute(main_meta);
304 // pub fn main() { ... }
305 let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
307 // If no test runner is provided we need to import the test crate
308 let main_body = if cx.test_runner.is_none() {
309 ecx.block(sp, vec![test_extern_stmt, call_test_main])
311 ecx.block(sp, vec![call_test_main])
314 let decl = ecx.fn_decl(vec![], ast::FnRetTy::Ty(main_ret_ty));
315 let sig = ast::FnSig { decl, header: ast::FnHeader::default(), span: sp };
316 let def = ast::Defaultness::Final;
318 ast::ItemKind::Fn(box ast::FnKind(def, sig, ast::Generics::default(), Some(main_body)));
320 // Honor the reexport_test_harness_main attribute
321 let main_id = match cx.reexport_test_harness_main {
322 Some(sym) => Ident::new(sym, sp.with_ctxt(SyntaxContext::root())),
323 None => Ident::new(sym::main, sp),
326 let main = P(ast::Item {
328 attrs: vec![main_attr],
329 id: ast::DUMMY_NODE_ID,
331 vis: ast::Visibility { span: sp, kind: ast::VisibilityKind::Public, tokens: None },
336 // Integrate the new item into existing module structures.
337 let main = AstFragment::Items(smallvec![main]);
338 cx.ext_cx.monotonic_expander().fully_expand_fragment(main).make_items().pop().unwrap()
341 /// Creates a slice containing every test like so:
342 /// &[&test1, &test2]
343 fn mk_tests_slice(cx: &TestCtxt<'_>, sp: Span) -> P<ast::Expr> {
344 debug!("building test vector from {} tests", cx.test_cases.len());
345 let ecx = &cx.ext_cx;
352 ecx.expr_addr_of(test.span, ecx.expr_path(ecx.path(test.span, vec![test.ident])))
358 fn is_test_case(sess: &Session, i: &ast::Item) -> bool {
359 sess.contains_name(&i.attrs, sym::rustc_test_marker)
364 sd: &rustc_errors::Handler,
366 ) -> Option<ast::Path> {
367 let test_attr = sess.find_by_name(&krate.attrs, sym::test_runner)?;
368 let meta_list = test_attr.meta_item_list()?;
369 let span = test_attr.span;
371 [single] => match single.meta_item() {
372 Some(meta_item) if meta_item.is_word() => return Some(meta_item.path.clone()),
373 _ => sd.struct_span_err(span, "`test_runner` argument must be a path").emit(),
375 _ => sd.struct_span_err(span, "`#![test_runner(..)]` accepts exactly 1 argument").emit(),