1 // Code that generates a test runner to run all the tests in a crate
4 use smallvec::{smallvec, SmallVec};
5 use rustc_target::spec::PanicStrategy;
6 use syntax::ast::{self, Ident};
8 use syntax::entry::{self, EntryPointType};
9 use syntax_expand::base::{ExtCtxt, Resolver};
10 use syntax_expand::expand::{AstFragment, ExpansionConfig};
11 use syntax::feature_gate::Features;
12 use syntax::mut_visit::{*, ExpectOne};
14 use syntax::sess::ParseSess;
15 use syntax::source_map::respan;
16 use syntax::symbol::{sym, Symbol};
17 use syntax_pos::{Span, DUMMY_SP};
18 use syntax_pos::hygiene::{AstPass, SyntaxContext, Transparency};
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
40 resolver: &mut dyn Resolver,
42 krate: &mut ast::Crate,
43 span_diagnostic: &errors::Handler,
45 panic_strategy: PanicStrategy,
46 platform_panic_strategy: PanicStrategy,
47 enable_panic_abort_tests: bool,
49 // Check for #![reexport_test_harness_main = "some_name"] which gives the
50 // main test function the name `some_name` without hygiene. This needs to be
51 // unconditional, so that the attribute is still marked as used in
53 let reexport_test_harness_main =
54 attr::first_attr_value_str_by_name(&krate.attrs, sym::reexport_test_harness_main);
56 // Do this here so that the test_runner crate attribute gets marked as used
57 // even in non-test builds
58 let test_runner = get_test_runner(span_diagnostic, &krate);
61 let panic_strategy = match (panic_strategy, enable_panic_abort_tests) {
62 (PanicStrategy::Abort, true) =>
64 (PanicStrategy::Abort, false) if panic_strategy == platform_panic_strategy => {
65 // Silently allow compiling with panic=abort on these platforms,
66 // but with old behavior (abort if a test fails).
69 (PanicStrategy::Abort, false) => {
70 span_diagnostic.err("building tests with panic=abort is not yet supported");
73 (PanicStrategy::Unwind, _) => PanicStrategy::Unwind,
75 generate_test_harness(sess, resolver, reexport_test_harness_main,
76 krate, features, panic_strategy, test_runner)
80 struct TestHarnessGenerator<'a> {
85 impl<'a> MutVisitor for TestHarnessGenerator<'a> {
86 fn visit_crate(&mut self, c: &mut ast::Crate) {
87 noop_visit_crate(c, self);
89 // Create a main function to run our tests
90 c.module.items.push(mk_main(&mut self.cx));
93 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
94 let mut item = i.into_inner();
95 if is_test_case(&item) {
96 debug!("this is a test item");
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() {
113 let parent = if item.id == ast::DUMMY_NODE_ID {
118 // Create an identifier that will hygienically resolve the test
119 // case name, even in another module.
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);
133 item.kind = ast::ItemKind::Mod(module);
138 fn visit_mac(&mut self, _mac: &mut ast::Mac) {
143 /// A folder used to remove any entry points (like fn main) because the harness
144 /// generator will provide its own
145 struct EntryPointCleaner {
146 // Current depth in the ast
151 impl MutVisitor for EntryPointCleaner {
152 fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
154 let item = noop_flat_map_item(i, self).expect_one("noop did something");
157 // Remove any #[main] or #[start] from the AST so it doesn't
158 // clash with the one we're going to add, but mark it as
159 // #[allow(dead_code)] to avoid printing warnings.
160 let item = match entry::entry_point_type(&item, self.depth) {
161 EntryPointType::MainNamed |
162 EntryPointType::MainAttr |
163 EntryPointType::Start =>
164 item.map(|ast::Item {id, ident, attrs, kind, vis, span, tokens}| {
165 let allow_ident = Ident::new(sym::allow, self.def_site);
166 let dc_nested = attr::mk_nested_word_item(
167 Ident::from_str_and_span("dead_code", self.def_site),
169 let allow_dead_code_item = attr::mk_list_item(allow_ident, vec![dc_nested]);
170 let allow_dead_code = attr::mk_attr_outer(allow_dead_code_item);
175 attrs: attrs.into_iter()
177 !attr.check_name(sym::main) && !attr.check_name(sym::start)
179 .chain(iter::once(allow_dead_code))
187 EntryPointType::None |
188 EntryPointType::OtherMain => item,
194 fn visit_mac(&mut self, _mac: &mut ast::Mac) {
199 /// Crawl over the crate, inserting test reexports and the test main function
200 fn generate_test_harness(sess: &ParseSess,
201 resolver: &mut dyn Resolver,
202 reexport_test_harness_main: Option<Symbol>,
203 krate: &mut ast::Crate,
205 panic_strategy: PanicStrategy,
206 test_runner: Option<ast::Path>) {
207 let mut econfig = ExpansionConfig::default("test".to_string());
208 econfig.features = Some(features);
210 let ext_cx = ExtCtxt::new(sess, econfig, resolver);
212 let expn_id = ext_cx.resolver.expansion_for_ast_pass(
214 AstPass::TestHarness,
215 &[sym::main, sym::test, sym::rustc_attrs],
218 let def_site = DUMMY_SP.with_def_site_ctxt(expn_id);
220 // Remove the entry points
221 let mut cleaner = EntryPointCleaner { depth: 0, def_site };
222 cleaner.visit_crate(krate);
228 test_cases: Vec::new(),
229 reexport_test_harness_main,
233 TestHarnessGenerator {
236 }.visit_crate(krate);
239 /// Creates a function item for use as the main function of a test build.
240 /// This function will call the `test_runner` as specified by the crate attribute
242 /// By default this expands to
246 /// extern crate test;
247 /// test::test_main_static(&[
254 /// Most of the Ident have the usual def-site hygiene for the AST pass. The
255 /// exception is the `test_const`s. These have a syntax context that has two
256 /// opaque marks: one from the expansion of `test` or `test_case`, and one
257 /// generated in `TestHarnessGenerator::flat_map_item`. When resolving this
258 /// identifier after failing to find a matching identifier in the root module
259 /// we remove the outer mark, and try resolving at its def-site, which will
260 /// then resolve to `test_const`.
262 /// The expansion here can be controlled by two attributes:
264 /// `reexport_test_harness_main` provides a different name for the `main`
265 /// function and `test_runner` provides a path that replaces
266 /// `test::test_main_static`.
267 fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
268 let sp = cx.def_site;
269 let ecx = &cx.ext_cx;
270 let test_id = Ident::new(sym::test, sp);
272 let runner_name = match cx.panic_strategy {
273 PanicStrategy::Unwind => "test_main_static",
274 PanicStrategy::Abort => "test_main_static_abort",
277 // test::test_main_static(...)
278 let mut test_runner = cx.test_runner.clone().unwrap_or(
279 ecx.path(sp, vec![test_id, ecx.ident_of(runner_name, sp)]));
281 test_runner.span = sp;
283 let test_main_path_expr = ecx.expr_path(test_runner);
284 let call_test_main = ecx.expr_call(sp, test_main_path_expr,
285 vec![mk_tests_slice(cx, sp)]);
286 let call_test_main = ecx.stmt_expr(call_test_main);
289 let test_extern_stmt = ecx.stmt_item(sp, ecx.item(sp,
292 ast::ItemKind::ExternCrate(None)
296 let main_meta = ecx.meta_word(sp, sym::main);
297 let main_attr = ecx.attribute(main_meta);
299 // pub fn main() { ... }
300 let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
302 // If no test runner is provided we need to import the test crate
303 let main_body = if cx.test_runner.is_none() {
304 ecx.block(sp, vec![test_extern_stmt, call_test_main])
306 ecx.block(sp, vec![call_test_main])
309 let main = ast::ItemKind::Fn(ecx.fn_decl(vec![], ast::FunctionRetTy::Ty(main_ret_ty)),
310 ast::FnHeader::default(),
311 ast::Generics::default(),
314 // Honor the reexport_test_harness_main attribute
315 let main_id = match cx.reexport_test_harness_main {
316 Some(sym) => Ident::new(sym, sp.with_ctxt(SyntaxContext::root())),
317 None => Ident::new(sym::main, sp),
320 let main = P(ast::Item {
322 attrs: vec![main_attr],
323 id: ast::DUMMY_NODE_ID,
325 vis: respan(sp, ast::VisibilityKind::Public),
330 // Integrate the new item into existing module structures.
331 let main = AstFragment::Items(smallvec![main]);
332 cx.ext_cx.monotonic_expander().fully_expand_fragment(main).make_items().pop().unwrap()
335 /// Creates a slice containing every test like so:
336 /// &[&test1, &test2]
337 fn mk_tests_slice(cx: &TestCtxt<'_>, sp: Span) -> P<ast::Expr> {
338 debug!("building test vector from {} tests", cx.test_cases.len());
339 let ref ecx = cx.ext_cx;
342 ecx.expr_vec_slice(sp,
343 cx.test_cases.iter().map(|test| {
344 ecx.expr_addr_of(test.span,
345 ecx.expr_path(ecx.path(test.span, vec![test.ident])))
349 fn is_test_case(i: &ast::Item) -> bool {
350 attr::contains_name(&i.attrs, sym::rustc_test_marker)
353 fn get_test_runner(sd: &errors::Handler, krate: &ast::Crate) -> Option<ast::Path> {
354 let test_attr = attr::find_by_name(&krate.attrs, sym::test_runner)?;
355 test_attr.meta_item_list().map(|meta_list| {
356 if meta_list.len() != 1 {
357 sd.span_fatal(test_attr.span,
358 "`#![test_runner(..)]` accepts exactly 1 argument").raise()
360 match meta_list[0].meta_item() {
361 Some(meta_item) if meta_item.is_word() => meta_item.path.clone(),
362 _ => sd.span_fatal(test_attr.span, "`test_runner` argument must be a path").raise()