fix: exclude internal JS files from coverage (#20448)

4 files changed, 87 insertions, 0 deletions

diff --git a/cli/tests/integration/coverage_tests.rs b/cli/tests/integration/coverage_tests.rs
index a8b3ec3a1..d8a11a624 100644
--- a/cli/tests/integration/coverage_tests.rs
+++ b/cli/tests/integration/coverage_tests.rs
@@ -1,8 +1,10 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
+use deno_core::serde_json;
 use std::fs;
 use test_util as util;
 use test_util::TempDir;
+use util::assert_starts_with;
 use util::env_vars_for_npm_tests;
 use util::TestContext;
 use util::TestContextBuilder;
@@ -439,3 +441,66 @@ fn no_transpiled_lines() {
 
   output.assert_exit_code(0);
 }
+
+#[test]
+fn no_internal_code() {
+  let context = TestContext::default();
+  let tempdir = context.temp_dir();
+  let tempdir = tempdir.path().join("cov");
+
+  let output = context
+    .new_command()
+    .args_vec(vec![
+      "test".to_string(),
+      "--quiet".to_string(),
+      format!("--coverage={}", tempdir),
+      "coverage/no_internal_code_test.ts".to_string(),
+    ])
+    .run();
+
+  output.assert_exit_code(0);
+  output.skip_output_check();
+
+  // Check that coverage files contain no internal urls
+  let paths = fs::read_dir(tempdir).unwrap();
+  for path in paths {
+    let unwrapped = path.unwrap().path();
+    let data = fs::read_to_string(&unwrapped.clone()).unwrap();
+
+    let value: serde_json::Value = serde_json::from_str(&data).unwrap();
+    let url = value["url"].as_str().unwrap();
+    assert_starts_with!(url, "file:");
+  }
+}
+
+#[test]
+fn no_internal_node_code() {
+  let context = TestContext::default();
+  let tempdir = context.temp_dir();
+  let tempdir = tempdir.path().join("cov");
+
+  let output = context
+    .new_command()
+    .args_vec(vec![
+      "test".to_string(),
+      "--quiet".to_string(),
+      "--no-check".to_string(),
+      format!("--coverage={}", tempdir),
+      "coverage/no_internal_node_code_test.ts".to_string(),
+    ])
+    .run();
+
+  output.assert_exit_code(0);
+  output.skip_output_check();
+
+  // Check that coverage files contain no internal urls
+  let paths = fs::read_dir(tempdir).unwrap();
+  for path in paths {
+    let unwrapped = path.unwrap().path();
+    let data = fs::read_to_string(&unwrapped.clone()).unwrap();
+
+    let value: serde_json::Value = serde_json::from_str(&data).unwrap();
+    let url = value["url"].as_str().unwrap();
+    assert_starts_with!(url, "file:");
+  }
+}
diff --git a/cli/tests/testdata/coverage/no_internal_code_test.ts b/cli/tests/testdata/coverage/no_internal_code_test.ts
new file mode 100644
index 000000000..0cf46d252
--- /dev/null
+++ b/cli/tests/testdata/coverage/no_internal_code_test.ts
@@ -0,0 +1,7 @@
+const add = (a: number, b: number) => a + b;
+
+Deno.test(function addTest() {
+  if (add(2, 3) !== 5) {
+    throw new Error("fail");
+  }
+});
diff --git a/cli/tests/testdata/coverage/no_internal_node_code_test.ts b/cli/tests/testdata/coverage/no_internal_node_code_test.ts
new file mode 100644
index 000000000..dc53e0c52
--- /dev/null
+++ b/cli/tests/testdata/coverage/no_internal_node_code_test.ts
@@ -0,0 +1,8 @@
+import * as path from "node:path";
+
+Deno.test(function test() {
+  const res = path.join("foo", "bar");
+  if (!res.includes("foo")) {
+    throw new Error("fail");
+  }
+});
diff --git a/cli/tools/coverage/mod.rs b/cli/tools/coverage/mod.rs
index 6dca349f7..2b8e67c82 100644
--- a/cli/tools/coverage/mod.rs
+++ b/cli/tools/coverage/mod.rs
@@ -127,6 +127,13 @@ impl CoverageCollector {
 
     let script_coverages = self.take_precise_coverage().await?.result;
     for script_coverage in script_coverages {
+      // Filter out internal JS files from being included in coverage reports
+      if script_coverage.url.starts_with("ext:")
+        || script_coverage.url.starts_with("[ext:")
+      {
+        continue;
+      }
+
       let filename = format!("{}.json", Uuid::new_v4());
       let filepath = self.dir.join(filename);