fix(cli): preserve comments in doc tests

cli/util/extract.rs

@@ -586,7 +586,10 @@ fn generate_pseudo_file(
         wrap_kind,
       }));
 
-  let source = deno_ast::swc::codegen::to_code(&transformed);
+  let source = deno_ast::swc::codegen::to_code_with_comments(
+    Some(&parsed.comments().as_single_threaded()),
+    &transformed,
+  );
 
   log::debug!("{}:\n{}", file.specifier, source);
 
@@ -1165,6 +1168,33 @@ Deno.test("file:///main.ts$3-6.ts", async ()=>{
           media_type: MediaType::TypeScript,
         }],
       },
+      // https://github.com/denoland/deno/issues/26728
+      Test {
+        input: Input {
+          source: r#"
+/**
+ * ```ts
+ * // @ts-expect-error: can only add numbers
+ * add('1', '2');
+ * ```
+ */
+export function add(first: number, second: number) {
+  return first + second;
+}
+"#,
+          specifier: "file:///main.ts",
+        },
+        expected: vec![Expected {
+          source: r#"import { add } from "file:///main.ts";
+Deno.test("file:///main.ts$3-7.ts", async ()=>{
+    // @ts-expect-error: can only add numbers
+    add('1', '2');
+});
+"#,
+          specifier: "file:///main.ts$3-7.ts",
+          media_type: MediaType::TypeScript,
+        }],
+      },
     ];
 
     for test in tests {
@@ -1376,6 +1406,31 @@ console.log(Foo);
           media_type: MediaType::TypeScript,
         }],
       },
+      // https://github.com/denoland/deno/issues/26728
+      Test {
+        input: Input {
+          source: r#"
+/**
+ * ```ts
+ * // @ts-expect-error: can only add numbers
+ * add('1', '2');
+ * ```
+ */
+export function add(first: number, second: number) {
+  return first + second;
+}
+"#,
+          specifier: "file:///main.ts",
+        },
+        expected: vec![Expected {
+          source: r#"import { add } from "file:///main.ts";
+// @ts-expect-error: can only add numbers
+add('1', '2');
+"#,
+          specifier: "file:///main.ts$3-7.ts",
+          media_type: MediaType::TypeScript,
+        }],
+      },
     ];
 
     for test in tests {

tests/specs/test/doc_ts_expect_error/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "test --doc mod.ts",
+  "exitCode": 0,
+  "output": "mod.out"
+}

tests/specs/test/doc_ts_expect_error/mod.out

@@ -0,0 +1,8 @@
+Check [WILDCARD]/mod.ts
+Check [WILDCARD]/mod.ts$2-10.ts
+running 0 tests from ./mod.ts
+running 1 test from ./mod.ts$2-10.ts
+[WILDCARD]/mod.ts$2-10.ts ... ok ([WILDCARD]ms)
+
+ok | 1 passed | 0 failed ([WILDCARD]ms)
+

tests/specs/test/doc_ts_expect_error/mod.ts

@@ -0,0 +1,13 @@
+/**
+ * ```ts
+ * import { add } from "./mod.ts";
+ *
+ * add(1, 2);
+ *
+ * // @ts-expect-error: can only add numbers
+ * add('1', '2');
+ * ```
+ */
+export function add(first: number, second: number) {
+  return first + second;
+}

tests/specs/test/markdown_ts_expect_error/__test__.jsonc

@@ -0,0 +1,5 @@
+{
+  "args": "test --doc main.md",
+  "exitCode": 0,
+  "output": "main.out"
+}

tests/specs/test/markdown_ts_expect_error/main.md

@@ -0,0 +1,8 @@
+# Documentation
+
+This test case checks if `@ts-expect-error` comment works as expected.
+
+```ts
+// @ts-expect-error
+const a: string = 42;
+```

tests/specs/test/markdown_ts_expect_error/main.out

@@ -0,0 +1,6 @@
+Check [WILDCARD]/main.md$5-9.ts
+running 1 test from ./main.md$5-9.ts
+[WILDCARD]/main.md$5-9.ts ... ok ([WILDCARD]ms)
+
+ok | 1 passed | 0 failed ([WILDCARD]ms)
+