1 // Code that generates a test runner to run all the tests in a crate
5 use rustc_ast::entry::EntryPointType;
6 use rustc_ast::mut_visit::{ExpectOne, *};
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::source_map::respan;
14 use rustc_span::symbol::{sym, Ident, Symbol};
15 use rustc_span::{Span, DUMMY_SP};
16 use rustc_target::spec::PanicStrategy;
17 use smallvec::{smallvec, SmallVec};
29 panic_strategy: PanicStrategy,
31 test_cases: Vec<Test>,
32 reexport_test_harness_main: Option<Symbol>,
33 test_runner: Option<ast::Path>,
36 // Traverse the crate, collecting all the test functions, eliding any
37 // existing main functions, and synthesizing a main test harness
38 pub fn inject(sess: &Session, resolver: &mut dyn ResolverExpand, krate: &mut ast::Crate) {
39 let span_diagnostic = sess.diagnostic();
40 let panic_strategy = sess.panic_strategy();
41 let platform_panic_strategy = sess.target.target.options.panic_strategy;
43 // Check for #![reexport_test_harness_main = "some_name"] which gives the
44 // main test function the name `some_name` without hygiene. This needs to be
45 // unconditional, so that the attribute is still marked as used in
47 let reexport_test_harness_main =
48 sess.first_attr_value_str_by_name(&krate.attrs, sym::reexport_test_harness_main);
50 // Do this here so that the test_runner crate attribute gets marked as used
51 // even in non-test builds
52 let test_runner = get_test_runner(sess, span_diagnostic, &krate);
55 let panic_strategy = match (panic_strategy, sess.opts.debugging_opts.panic_abort_tests) {
56 (PanicStrategy::Abort, true) => PanicStrategy::Abort,
57 (PanicStrategy::Abort, false) => {
58 if panic_strategy == platform_panic_strategy {
59 // Silently allow compiling with panic=abort on these platforms,
60 // but with old behavior (abort if a test fails).
63 "building tests with panic=abort is not supported \
64 without `-Zpanic_abort_tests`",
69 (PanicStrategy::Unwind, _) => PanicStrategy::Unwind,
71 generate_test_harness(
74 reexport_test_harness_main,
76 &sess.features_untracked(),
83 struct TestHarnessGenerator<'a> {
88 impl<'a> MutVisitor for TestHarnessGenerator<'a> {
89 fn visit_crate(&mut self, c: &mut ast::Crate) {
90 noop_visit_crate(c, self);
92 // Create a main function to run our tests
93 c.module.items.push(mk_main(&mut self.cx));
96 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
97 let mut item = i.into_inner();
98 if is_test_case(&self.cx.ext_cx.sess, &item) {
99 debug!("this is a test item");
101 let test = Test { span: item.span, ident: item.ident };
102 self.tests.push(test);
105 // We don't want to recurse into anything other than mods, since
106 // mods or tests inside of functions will break things
107 if let ast::ItemKind::Mod(mut module) = item.kind {
108 let tests = mem::take(&mut self.tests);
109 noop_visit_mod(&mut module, self);
110 let mut tests = mem::replace(&mut self.tests, tests);
112 if !tests.is_empty() {
114 if item.id == ast::DUMMY_NODE_ID { ast::CRATE_NODE_ID } else { item.id };
115 // Create an identifier that will hygienically resolve the test
116 // case name, even in another module.
117 let expn_id = self.cx.ext_cx.resolver.expansion_for_ast_pass(
119 AstPass::TestHarness,
123 for test in &mut tests {
124 // See the comment on `mk_main` for why we're using
125 // `apply_mark` directly.
126 test.ident.span = test.ident.span.apply_mark(expn_id, Transparency::Opaque);
128 self.cx.test_cases.extend(tests);
130 item.kind = ast::ItemKind::Mod(module);
135 fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
140 // Beware, this is duplicated in librustc_passes/entry.rs (with
141 // `rustc_hir::Item`), so make sure to keep them in sync.
142 fn entry_point_type(sess: &Session, item: &ast::Item, depth: usize) -> EntryPointType {
144 ast::ItemKind::Fn(..) => {
145 if sess.contains_name(&item.attrs, sym::start) {
146 EntryPointType::Start
147 } else if sess.contains_name(&item.attrs, sym::main) {
148 EntryPointType::MainAttr
149 } else if item.ident.name == sym::main {
151 // This is a top-level function so can be 'main'
152 EntryPointType::MainNamed
154 EntryPointType::OtherMain
160 _ => EntryPointType::None,
163 /// A folder used to remove any entry points (like fn main) because the harness
164 /// generator will provide its own
165 struct EntryPointCleaner<'a> {
166 // Current depth in the ast
172 impl<'a> MutVisitor for EntryPointCleaner<'a> {
173 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
175 let item = noop_flat_map_item(i, self).expect_one("noop did something");
178 // Remove any #[main] or #[start] from the AST so it doesn't
179 // clash with the one we're going to add, but mark it as
180 // #[allow(dead_code)] to avoid printing warnings.
181 let item = match entry_point_type(self.sess, &item, self.depth) {
182 EntryPointType::MainNamed | EntryPointType::MainAttr | EntryPointType::Start => item
183 .map(|ast::Item { id, ident, attrs, kind, vis, span, tokens }| {
184 let allow_ident = Ident::new(sym::allow, self.def_site);
186 attr::mk_nested_word_item(Ident::new(sym::dead_code, self.def_site));
187 let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
188 let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
192 !self.sess.check_name(attr, sym::main)
193 && !self.sess.check_name(attr, sym::start)
195 .chain(iter::once(allow_dead_code))
198 ast::Item { id, ident, attrs, kind, vis, span, tokens }
200 EntryPointType::None | EntryPointType::OtherMain => item,
206 fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
211 /// Crawl over the crate, inserting test reexports and the test main function
212 fn generate_test_harness(
214 resolver: &mut dyn ResolverExpand,
215 reexport_test_harness_main: Option<Symbol>,
216 krate: &mut ast::Crate,
218 panic_strategy: PanicStrategy,
219 test_runner: Option<ast::Path>,
221 let mut econfig = ExpansionConfig::default("test".to_string());
222 econfig.features = Some(features);
224 let ext_cx = ExtCtxt::new(sess, econfig, resolver, None);
226 let expn_id = ext_cx.resolver.expansion_for_ast_pass(
228 AstPass::TestHarness,
229 &[sym::main, sym::test, sym::rustc_attrs],
232 let def_site = DUMMY_SP.with_def_site_ctxt(expn_id);
234 // Remove the entry points
235 let mut cleaner = EntryPointCleaner { sess, depth: 0, def_site };
236 cleaner.visit_crate(krate);
242 test_cases: Vec::new(),
243 reexport_test_harness_main,
247 TestHarnessGenerator { cx, tests: Vec::new() }.visit_crate(krate);
250 /// Creates a function item for use as the main function of a test build.
251 /// This function will call the `test_runner` as specified by the crate attribute
253 /// By default this expands to
258 /// extern crate test;
259 /// test::test_main_static(&[
267 /// Most of the Ident have the usual def-site hygiene for the AST pass. The
268 /// exception is the `test_const`s. These have a syntax context that has two
269 /// opaque marks: one from the expansion of `test` or `test_case`, and one
270 /// generated in `TestHarnessGenerator::flat_map_item`. When resolving this
271 /// identifier after failing to find a matching identifier in the root module
272 /// we remove the outer mark, and try resolving at its def-site, which will
273 /// then resolve to `test_const`.
275 /// The expansion here can be controlled by two attributes:
277 /// [`TestCtxt::reexport_test_harness_main`] provides a different name for the `main`
278 /// function and [`TestCtxt::test_runner`] provides a path that replaces
279 /// `test::test_main_static`.
280 fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
281 let sp = cx.def_site;
282 let ecx = &cx.ext_cx;
283 let test_id = Ident::new(sym::test, sp);
285 let runner_name = match cx.panic_strategy {
286 PanicStrategy::Unwind => "test_main_static",
287 PanicStrategy::Abort => "test_main_static_abort",
290 // test::test_main_static(...)
291 let mut test_runner = cx
294 .unwrap_or(ecx.path(sp, vec![test_id, Ident::from_str_and_span(runner_name, sp)]));
296 test_runner.span = sp;
298 let test_main_path_expr = ecx.expr_path(test_runner);
299 let call_test_main = ecx.expr_call(sp, test_main_path_expr, vec![mk_tests_slice(cx, sp)]);
300 let call_test_main = ecx.stmt_expr(call_test_main);
303 let test_extern_stmt =
304 ecx.stmt_item(sp, ecx.item(sp, test_id, vec![], ast::ItemKind::ExternCrate(None)));
307 let main_meta = ecx.meta_word(sp, sym::main);
308 let main_attr = ecx.attribute(main_meta);
310 // pub fn main() { ... }
311 let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
313 // If no test runner is provided we need to import the test crate
314 let main_body = if cx.test_runner.is_none() {
315 ecx.block(sp, vec![test_extern_stmt, call_test_main])
317 ecx.block(sp, vec![call_test_main])
320 let decl = ecx.fn_decl(vec![], ast::FnRetTy::Ty(main_ret_ty));
321 let sig = ast::FnSig { decl, header: ast::FnHeader::default() };
322 let def = ast::Defaultness::Final;
323 let main = ast::ItemKind::Fn(def, sig, ast::Generics::default(), Some(main_body));
325 // Honor the reexport_test_harness_main attribute
326 let main_id = match cx.reexport_test_harness_main {
327 Some(sym) => Ident::new(sym, sp.with_ctxt(SyntaxContext::root())),
328 None => Ident::new(sym::main, sp),
331 let main = P(ast::Item {
333 attrs: vec![main_attr],
334 id: ast::DUMMY_NODE_ID,
336 vis: respan(sp, ast::VisibilityKind::Public),
341 // Integrate the new item into existing module structures.
342 let main = AstFragment::Items(smallvec![main]);
343 cx.ext_cx.monotonic_expander().fully_expand_fragment(main).make_items().pop().unwrap()
346 /// Creates a slice containing every test like so:
347 /// &[&test1, &test2]
348 fn mk_tests_slice(cx: &TestCtxt<'_>, sp: Span) -> P<ast::Expr> {
349 debug!("building test vector from {} tests", cx.test_cases.len());
350 let ecx = &cx.ext_cx;
357 ecx.expr_addr_of(test.span, ecx.expr_path(ecx.path(test.span, vec![test.ident])))
363 fn is_test_case(sess: &Session, i: &ast::Item) -> bool {
364 sess.contains_name(&i.attrs, sym::rustc_test_marker)
369 sd: &rustc_errors::Handler,
371 ) -> Option<ast::Path> {
372 let test_attr = sess.find_by_name(&krate.attrs, sym::test_runner)?;
373 let meta_list = test_attr.meta_item_list()?;
374 let span = test_attr.span;
376 [single] => match single.meta_item() {
377 Some(meta_item) if meta_item.is_word() => return Some(meta_item.path.clone()),
378 _ => sd.struct_span_err(span, "`test_runner` argument must be a path").emit(),
380 _ => sd.struct_span_err(span, "`#![test_runner(..)]` accepts exactly 1 argument").emit(),