fix(coverage): add tooltip to line count in html report (denoland#23971)

closes denoland#21582

cli/tools/coverage/reporter.rs

@@ -644,7 +644,7 @@ impl HtmlCoverageReporter {
  if *count == 0 {
  "<span class='cline-any cline-no'>&nbsp</span>".to_string()
  } else {
- format!("<span class='cline-any cline-yes'>x{count}</span>")
+ format!("<span class='cline-any cline-yes' title='This line is covered {count} time{}'>x{count}</span>", if *count > 1 { "s" } else { "" })
  }
  } else {
  "<span class='cline-any cline-neutral'>&nbsp</span>".to_string()

tests/integration/coverage_tests.rs

@@ -441,6 +441,12 @@ fn no_internal_node_code() {
 
 #[test]
 fn test_html_reporter() {
+ // This test case generates a html coverage report of test cases in /tests/testdata/coverage/multisource
+ // You can get the same reports in ./cov_html by running the following command:
+ // ```
+ // ./target/debug/deno test --coverage=cov_html tests/testdata/coverage/multisource
+ // ./target/debug/deno coverage --html cov_html
+ // ```
  let context = TestContext::default();
  let tempdir = context.temp_dir();
  let tempdir = tempdir.path().join("cov");
@@ -481,6 +487,9 @@ fn test_html_reporter() {
 
  let foo_ts_html = tempdir.join("html").join("foo.ts.html").read_to_string();
  assert_contains!(foo_ts_html, "<h1>Coverage report for foo.ts</h1>");
+ // Check that line count has correct title attribute
+ assert_contains!(foo_ts_html, "<span class='cline-any cline-yes' title='This line is covered 1 time'>x1</span>");
+ assert_contains!(foo_ts_html, "<span class='cline-any cline-yes' title='This line is covered 3 times'>x3</span>");
 
  let bar_ts_html = tempdir.join("html").join("bar.ts.html").read_to_string();
  assert_contains!(bar_ts_html, "<h1>Coverage report for bar.ts</h1>");