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 TestHarnessGenerator<'_> {
88 fn add_test_cases(&mut self, node_id: ast::NodeId, span: Span, prev_tests: Vec<Test>) {
89 let mut tests = mem::replace(&mut self.tests, prev_tests);
91 if !tests.is_empty() {
92 // Create an identifier that will hygienically resolve the test
93 // case name, even in another module.
94 let expn_id = self.cx.ext_cx.resolver.expansion_for_ast_pass(
100 for test in &mut tests {
101 // See the comment on `mk_main` for why we're using
102 // `apply_mark` directly.
104 test.ident.span.apply_mark(expn_id.to_expn_id(), Transparency::Opaque);
106 self.cx.test_cases.extend(tests);
111 impl<'a> MutVisitor for TestHarnessGenerator<'a> {
112 fn visit_crate(&mut self, c: &mut ast::Crate) {
113 let prev_tests = mem::take(&mut self.tests);
114 noop_visit_crate(c, self);
115 self.add_test_cases(ast::CRATE_NODE_ID, c.spans.inner_span, prev_tests);
117 // Create a main function to run our tests
118 c.items.push(mk_main(&mut self.cx));
121 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
122 let mut item = i.into_inner();
123 if is_test_case(&self.cx.ext_cx.sess, &item) {
124 debug!("this is a test item");
126 let test = Test { span: item.span, ident: item.ident };
127 self.tests.push(test);
130 // We don't want to recurse into anything other than mods, since
131 // mods or tests inside of functions will break things
132 if let ast::ItemKind::Mod(_, ModKind::Loaded(.., ref spans)) = item.kind {
133 let ast::ModSpans { inner_span: span, inject_use_span: _ } = *spans;
134 let prev_tests = mem::take(&mut self.tests);
135 noop_visit_item_kind(&mut item.kind, self);
136 self.add_test_cases(item.id, span, prev_tests);
142 // Beware, this is duplicated in librustc_passes/entry.rs (with
143 // `rustc_hir::Item`), so make sure to keep them in sync.
144 fn entry_point_type(sess: &Session, item: &ast::Item, depth: usize) -> EntryPointType {
146 ast::ItemKind::Fn(..) => {
147 if sess.contains_name(&item.attrs, sym::start) {
148 EntryPointType::Start
149 } else if sess.contains_name(&item.attrs, sym::rustc_main) {
150 EntryPointType::MainAttr
151 } else if item.ident.name == sym::main {
153 // This is a top-level function so can be 'main'
154 EntryPointType::MainNamed
156 EntryPointType::OtherMain
162 _ => EntryPointType::None,
165 /// A folder used to remove any entry points (like fn main) because the harness
166 /// generator will provide its own
167 struct EntryPointCleaner<'a> {
168 // Current depth in the ast
174 impl<'a> MutVisitor for EntryPointCleaner<'a> {
175 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
177 let item = noop_flat_map_item(i, self).expect_one("noop did something");
180 // Remove any #[main] or #[start] from the AST so it doesn't
181 // clash with the one we're going to add, but mark it as
182 // #[allow(dead_code)] to avoid printing warnings.
183 let item = match entry_point_type(self.sess, &item, self.depth) {
184 EntryPointType::MainNamed | EntryPointType::MainAttr | EntryPointType::Start => item
185 .map(|ast::Item { id, ident, attrs, kind, vis, span, tokens }| {
186 let allow_ident = Ident::new(sym::allow, self.def_site);
188 attr::mk_nested_word_item(Ident::new(sym::dead_code, self.def_site));
189 let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
190 let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
194 !attr.has_name(sym::rustc_main) && !attr.has_name(sym::start)
196 .chain(iter::once(allow_dead_code))
199 ast::Item { id, ident, attrs, kind, vis, span, tokens }
201 EntryPointType::None | EntryPointType::OtherMain => item,
208 /// Crawl over the crate, inserting test reexports and the test main function
209 fn generate_test_harness(
211 resolver: &mut dyn ResolverExpand,
212 reexport_test_harness_main: Option<Symbol>,
213 krate: &mut ast::Crate,
215 panic_strategy: PanicStrategy,
216 test_runner: Option<ast::Path>,
218 let mut econfig = ExpansionConfig::default("test".to_string());
219 econfig.features = Some(features);
221 let ext_cx = ExtCtxt::new(sess, econfig, resolver, None);
223 let expn_id = ext_cx.resolver.expansion_for_ast_pass(
225 AstPass::TestHarness,
226 &[sym::test, sym::rustc_attrs],
229 let def_site = DUMMY_SP.with_def_site_ctxt(expn_id.to_expn_id());
231 // Remove the entry points
232 let mut cleaner = EntryPointCleaner { sess, depth: 0, def_site };
233 cleaner.visit_crate(krate);
239 test_cases: Vec::new(),
240 reexport_test_harness_main,
244 TestHarnessGenerator { cx, tests: Vec::new() }.visit_crate(krate);
247 /// Creates a function item for use as the main function of a test build.
248 /// This function will call the `test_runner` as specified by the crate attribute
250 /// By default this expands to
255 /// extern crate test;
256 /// test::test_main_static(&[
264 /// Most of the Ident have the usual def-site hygiene for the AST pass. The
265 /// exception is the `test_const`s. These have a syntax context that has two
266 /// opaque marks: one from the expansion of `test` or `test_case`, and one
267 /// generated in `TestHarnessGenerator::flat_map_item`. When resolving this
268 /// identifier after failing to find a matching identifier in the root module
269 /// we remove the outer mark, and try resolving at its def-site, which will
270 /// then resolve to `test_const`.
272 /// The expansion here can be controlled by two attributes:
274 /// [`TestCtxt::reexport_test_harness_main`] provides a different name for the `main`
275 /// function and [`TestCtxt::test_runner`] provides a path that replaces
276 /// `test::test_main_static`.
277 fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
278 let sp = cx.def_site;
279 let ecx = &cx.ext_cx;
280 let test_id = Ident::new(sym::test, sp);
282 let runner_name = match cx.panic_strategy {
283 PanicStrategy::Unwind => "test_main_static",
284 PanicStrategy::Abort => "test_main_static_abort",
287 // test::test_main_static(...)
288 let mut test_runner = cx
291 .unwrap_or_else(|| ecx.path(sp, vec![test_id, Ident::from_str_and_span(runner_name, sp)]));
293 test_runner.span = sp;
295 let test_main_path_expr = ecx.expr_path(test_runner);
296 let call_test_main = ecx.expr_call(sp, test_main_path_expr, vec![mk_tests_slice(cx, sp)]);
297 let call_test_main = ecx.stmt_expr(call_test_main);
300 let test_extern_stmt =
301 ecx.stmt_item(sp, ecx.item(sp, test_id, vec![], ast::ItemKind::ExternCrate(None)));
304 let main_meta = ecx.meta_word(sp, sym::rustc_main);
305 let main_attr = ecx.attribute(main_meta);
307 // pub fn main() { ... }
308 let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
310 // If no test runner is provided we need to import the test crate
311 let main_body = if cx.test_runner.is_none() {
312 ecx.block(sp, vec![test_extern_stmt, call_test_main])
314 ecx.block(sp, vec![call_test_main])
317 let decl = ecx.fn_decl(vec![], ast::FnRetTy::Ty(main_ret_ty));
318 let sig = ast::FnSig { decl, header: ast::FnHeader::default(), span: sp };
319 let defaultness = ast::Defaultness::Final;
320 let main = ast::ItemKind::Fn(Box::new(ast::Fn {
323 generics: ast::Generics::default(),
324 body: Some(main_body),
327 // Honor the reexport_test_harness_main attribute
328 let main_id = match cx.reexport_test_harness_main {
329 Some(sym) => Ident::new(sym, sp.with_ctxt(SyntaxContext::root())),
330 None => Ident::new(sym::main, sp),
333 let main = P(ast::Item {
335 attrs: vec![main_attr],
336 id: ast::DUMMY_NODE_ID,
338 vis: ast::Visibility { span: sp, kind: ast::VisibilityKind::Public, tokens: None },
343 // Integrate the new item into existing module structures.
344 let main = AstFragment::Items(smallvec![main]);
345 cx.ext_cx.monotonic_expander().fully_expand_fragment(main).make_items().pop().unwrap()
348 /// Creates a slice containing every test like so:
349 /// &[&test1, &test2]
350 fn mk_tests_slice(cx: &TestCtxt<'_>, sp: Span) -> P<ast::Expr> {
351 debug!("building test vector from {} tests", cx.test_cases.len());
352 let ecx = &cx.ext_cx;
359 ecx.expr_addr_of(test.span, ecx.expr_path(ecx.path(test.span, vec![test.ident])))
365 fn is_test_case(sess: &Session, i: &ast::Item) -> bool {
366 sess.contains_name(&i.attrs, sym::rustc_test_marker)
371 sd: &rustc_errors::Handler,
373 ) -> Option<ast::Path> {
374 let test_attr = sess.find_by_name(&krate.attrs, sym::test_runner)?;
375 let meta_list = test_attr.meta_item_list()?;
376 let span = test_attr.span;
378 [single] => match single.meta_item() {
379 Some(meta_item) if meta_item.is_word() => return Some(meta_item.path.clone()),
381 sd.struct_span_err(span, "`test_runner` argument must be a path").emit();
385 sd.struct_span_err(span, "`#![test_runner(..)]` accepts exactly 1 argument").emit();