Rewrite inline parser test infra to generated proper rust test cases

2 files changed, 116 insertions, 54 deletions

diff --git a/src/tools/rust-analyzer/xtask/src/codegen.rs b/src/tools/rust-analyzer/xtask/src/codegen.rs
index 2491952f52f..aeb0c00ae6a 100644
--- a/src/tools/rust-analyzer/xtask/src/codegen.rs
+++ b/src/tools/rust-analyzer/xtask/src/codegen.rs
@@ -162,12 +162,12 @@ fn add_preamble(cg: CodegenType, mut text: String) -> String {
 /// Checks that the `file` has the specified `contents`. If that is not the
 /// case, updates the file and then fails the test.
 #[allow(clippy::print_stderr)]
-fn ensure_file_contents(cg: CodegenType, file: &Path, contents: &str, check: bool) {
+fn ensure_file_contents(cg: CodegenType, file: &Path, contents: &str, check: bool) -> bool {
     let contents = normalize_newlines(contents);
     if let Ok(old_contents) = fs::read_to_string(file) {
         if normalize_newlines(&old_contents) == contents {
             // File is already up to date.
-            return;
+            return false;
         }
     }
 
@@ -194,6 +194,7 @@ fn ensure_file_contents(cg: CodegenType, file: &Path, contents: &str, check: boo
             let _ = fs::create_dir_all(parent);
         }
         fs::write(file, contents).unwrap();
+        true
     }
 }
 
diff --git a/src/tools/rust-analyzer/xtask/src/codegen/parser_inline_tests.rs b/src/tools/rust-analyzer/xtask/src/codegen/parser_inline_tests.rs
index 5983b06e1b9..3a9073b4e40 100644
--- a/src/tools/rust-analyzer/xtask/src/codegen/parser_inline_tests.rs
+++ b/src/tools/rust-analyzer/xtask/src/codegen/parser_inline_tests.rs
@@ -6,68 +6,132 @@ use std::{
     collections::HashMap,
     fs, iter,
     path::{Path, PathBuf},
+    time::SystemTime,
 };
 
+use anyhow::Result;
+use itertools::Itertools as _;
+
 use crate::{
-    codegen::{ensure_file_contents, CommentBlock},
+    codegen::{ensure_file_contents, reformat, CommentBlock},
     project_root,
     util::list_rust_files,
 };
 
+const PARSER_CRATE_ROOT: &str = "crates/parser";
+const PARSER_TEST_DATA: &str = "crates/parser/test_data";
+const PARSER_TEST_DATA_INLINE: &str = "crates/parser/test_data/parser/inline";
+
 pub(crate) fn generate(check: bool) {
-    let grammar_dir = project_root().join(Path::new("crates/parser/src/grammar"));
-    let tests = tests_from_dir(&grammar_dir);
+    let tests = tests_from_dir(
+        &project_root().join(Path::new(&format!("{PARSER_CRATE_ROOT}/src/grammar"))),
+    );
 
-    install_tests(&tests.ok, "crates/parser/test_data/parser/inline/ok", check);
-    install_tests(&tests.err, "crates/parser/test_data/parser/inline/err", check);
+    let mut some_file_was_updated = false;
+    some_file_was_updated |=
+        install_tests(&tests.ok, &format!("{PARSER_TEST_DATA_INLINE}/ok"), check).unwrap();
+    some_file_was_updated |=
+        install_tests(&tests.err, &format!("{PARSER_TEST_DATA_INLINE}/err"), check).unwrap();
 
-    fn install_tests(tests: &HashMap<String, Test>, into: &str, check: bool) {
-        let tests_dir = project_root().join(into);
-        if !tests_dir.is_dir() {
-            fs::create_dir_all(&tests_dir).unwrap();
-        }
-        // ok is never actually read, but it needs to be specified to create a Test in existing_tests
-        let existing = existing_tests(&tests_dir, true);
-        if let Some(t) = existing.keys().find(|&t| !tests.contains_key(t)) {
-            panic!("Test is deleted: {t}");
-        }
+    if some_file_was_updated {
+        let _ = fs::File::open(&format!("{PARSER_CRATE_ROOT}/src/tests.rs"))
+            .unwrap()
+            .set_modified(SystemTime::now());
 
-        let mut new_idx = existing.len() + 1;
-        for (name, test) in tests {
-            let path = match existing.get(name) {
-                Some((path, _test)) => path.clone(),
-                None => {
-                    let file_name = format!("{new_idx:04}_{name}.rs");
-                    new_idx += 1;
-                    tests_dir.join(file_name)
+        let ok_tests = tests.ok.keys().sorted().map(|k| {
+            let test_name = quote::format_ident!("{}", k);
+            let test_file = format!("test_data/parser/inline/ok/{test_name}.rs");
+            quote::quote! {
+                #[test]
+                fn #test_name() {
+                    run_and_expect_no_errors(#test_file);
                 }
-            };
-            ensure_file_contents(crate::flags::CodegenType::ParserTests, &path, &test.text, check);
+            }
+        });
+        let err_tests = tests.err.keys().sorted().map(|k| {
+            let test_name = quote::format_ident!("{}", k);
+            let test_file = format!("test_data/parser/inline/err/{test_name}.rs");
+            quote::quote! {
+                #[test]
+                fn #test_name() {
+                    run_and_expect_errors(#test_file);
+                }
+            }
+        });
+
+        let output = quote::quote! {
+            mod ok {
+                use crate::tests::run_and_expect_no_errors;
+                #(#ok_tests)*
+            }
+            mod err {
+                use crate::tests::run_and_expect_errors;
+                #(#err_tests)*
+            }
+        };
+
+        let pretty = reformat(output.to_string());
+        ensure_file_contents(
+            crate::flags::CodegenType::ParserTests,
+            format!("{PARSER_TEST_DATA}/generated/runner.rs").as_ref(),
+            &pretty,
+            check,
+        );
+    }
+}
+
+fn install_tests(tests: &HashMap<String, Test>, into: &str, check: bool) -> Result<bool> {
+    let tests_dir = project_root().join(into);
+    if !tests_dir.is_dir() {
+        fs::create_dir_all(&tests_dir)?;
+    }
+    let existing = existing_tests(&tests_dir, TestKind::Ok)?;
+    if let Some((t, (path, _))) = existing.iter().find(|&(t, _)| !tests.contains_key(t)) {
+        panic!("Test `{t}` is deleted: {}", path.display());
+    }
+
+    let mut some_file_was_updated = false;
+
+    for (name, test) in tests {
+        let path = match existing.get(name) {
+            Some((path, _test)) => path.clone(),
+            None => tests_dir.join(name).with_extension("rs"),
+        };
+        if ensure_file_contents(crate::flags::CodegenType::ParserTests, &path, &test.text, check) {
+            some_file_was_updated = true;
         }
     }
+
+    Ok(some_file_was_updated)
 }
 
 #[derive(Debug)]
 struct Test {
-    name: String,
-    text: String,
-    ok: bool,
+    pub name: String,
+    pub text: String,
+    pub kind: TestKind,
+}
+
+#[derive(Copy, Clone, Debug)]
+enum TestKind {
+    Ok,
+    Err,
 }
 
 #[derive(Default, Debug)]
 struct Tests {
-    ok: HashMap<String, Test>,
-    err: HashMap<String, Test>,
+    pub ok: HashMap<String, Test>,
+    pub err: HashMap<String, Test>,
 }
 
 fn collect_tests(s: &str) -> Vec<Test> {
     let mut res = Vec::new();
     for comment_block in CommentBlock::extract_untagged(s) {
         let first_line = &comment_block.contents[0];
-        let (name, ok) = if let Some(name) = first_line.strip_prefix("test ") {
-            (name.to_owned(), true)
+        let (name, kind) = if let Some(name) = first_line.strip_prefix("test ") {
+            (name.to_owned(), TestKind::Ok)
         } else if let Some(name) = first_line.strip_prefix("test_err ") {
-            (name.to_owned(), false)
+            (name.to_owned(), TestKind::Err)
         } else {
             continue;
         };
@@ -78,7 +142,7 @@ fn collect_tests(s: &str) -> Vec<Test> {
             .collect::<Vec<_>>()
             .join("\n");
         assert!(!text.trim().is_empty() && text.ends_with('\n'));
-        res.push(Test { name, text, ok })
+        res.push(Test { name, text, kind })
     }
     res
 }
@@ -96,7 +160,7 @@ fn tests_from_dir(dir: &Path) -> Tests {
         let text = fs::read_to_string(path).unwrap();
 
         for test in collect_tests(&text) {
-            if test.ok {
+            if let TestKind::Ok = test.kind {
                 if let Some(old_test) = res.ok.insert(test.name.clone(), test) {
                     panic!("Duplicate test: {}", old_test.name);
                 }
@@ -107,25 +171,22 @@ fn tests_from_dir(dir: &Path) -> Tests {
     }
 }
 
-fn existing_tests(dir: &Path, ok: bool) -> HashMap<String, (PathBuf, Test)> {
-    let mut res = HashMap::default();
-    for file in fs::read_dir(dir).unwrap() {
-        let file = file.unwrap();
-        let path = file.path();
-        if path.extension().unwrap_or_default() != "rs" {
-            continue;
-        }
-        let name = {
-            let file_name = path.file_name().unwrap().to_str().unwrap();
-            file_name[5..file_name.len() - 3].to_string()
-        };
-        let text = fs::read_to_string(&path).unwrap();
-        let test = Test { name: name.clone(), text, ok };
-        if let Some(old) = res.insert(name, (path, test)) {
-            println!("Duplicate test: {old:?}");
+fn existing_tests(dir: &Path, ok: TestKind) -> Result<HashMap<String, (PathBuf, Test)>> {
+    let mut res = HashMap::new();
+    for file in fs::read_dir(dir)? {
+        let path = file?.path();
+        let rust_file = path.extension().and_then(|ext| ext.to_str()) == Some("rs");
+
+        if rust_file {
+            let name = path.file_stem().map(|x| x.to_string_lossy().to_string()).unwrap();
+            let text = fs::read_to_string(&path)?;
+            let test = Test { name: name.clone(), text, kind: ok };
+            if let Some(old) = res.insert(name, (path, test)) {
+                println!("Duplicate test: {:?}", old);
+            }
         }
     }
-    res
+    Ok(res)
 }
 
 #[test]