test_runner: mark ignored lcov branches covered

lib/internal/test_runner/coverage.js

@@ -43,6 +43,7 @@ const kCoverageFileRegex = /^coverage-(\d+)-(\d{13})-(\d+)\.json$/;
 const kIgnoreRegex = /\/\* node:coverage ignore next (?<count>\d+ )?\*\//;
 const kLineEndingRegex = /\r?\n$/u;
 const kLineSplitRegex = /(?<=\r?\n)/u;
+const kNonExecutableLineRegex = /^\s*(?:$|[{}()[\];,]+|\/\/.*|\/\*.*\*\/)\s*$/;
 const kStatusRegex = /\/\* node:coverage (?<status>enable|disable) \*\//;
 
 class CoverageLine {
@@ -193,13 +194,15 @@ class TestCoverage {
           ObjectAssign(range, mapRangeToLines(range, lines));
 
           if (isBlockCoverage) {
+            const branchCount = isIgnoredBranchRange(range) ? 1 : range.count;
+
             ArrayPrototypePush(branchReports, {
               __proto__: null,
               line: range.lines[0]?.line,
-              count: range.count,
+              count: branchCount,
             });
 
-            if (range.count !== 0 ||
+            if (branchCount !== 0 ||
                 range.ignoredLines === range.lines.length) {
               branchesCovered++;
             }
@@ -585,6 +588,26 @@ function mapRangeToLines(range, lines) {
   return { __proto__: null, lines: mappedLines, ignoredLines };
 }
 
+function isIgnoredBranchRange(range) {
+  if (range.count !== 0 || range.ignoredLines === 0) {
+    return false;
+  }
+
+  for (let i = 0; i < range.lines.length; ++i) {
+    const line = range.lines[i];
+
+    if (line.ignore ||
+        line.count > 0 ||
+        RegExpPrototypeExec(kNonExecutableLineRegex, line.src) !== null) {
+      continue;
+    }
+
+    return false;
+  }
+
+  return true;
+}
+
 function mergeCoverageScripts(oldScript, newScript) {
   // Merge the functions from the new coverage into the functions from the
   // existing (merged) coverage.

test/fixtures/test-runner/coverage-ignored-branch.js

@@ -0,0 +1,11 @@
+'use strict';
+
+function getValue(condition) {
+  if (condition) {
+    return 'truthy';
+  }
+  /* node:coverage ignore next */
+  return 'falsy';
+}
+
+module.exports = { getValue };

test/fixtures/test-runner/coverage-ignored-branch.test.js

@@ -0,0 +1,9 @@
+'use strict';
+
+const assert = require('node:assert');
+const test = require('node:test');
+const { getValue } = require('./coverage-ignored-branch');
+
+test('returns truthy', () => {
+  assert.strictEqual(getValue(true), 'truthy');
+});

test/parallel/test-runner-coverage.js

@@ -2,7 +2,7 @@
 const common = require('../common');
 const assert = require('node:assert');
 const { spawnSync } = require('node:child_process');
-const { readdirSync } = require('node:fs');
+const { readFileSync, readdirSync } = require('node:fs');
 const { test } = require('node:test');
 const fixtures = require('../common/fixtures');
 const tmpdir = require('../common/tmpdir');
@@ -333,6 +333,36 @@ test('coverage reports on lines, functions, and branches', skipIfNoInspector, as
   });
 });
 
+test('lcov reporter excludes ignored branch ranges', skipIfNoInspector, () => {
+  const fixture = fixtures.path('test-runner', 'coverage-ignored-branch.test.js');
+  const destination = tmpdir.resolve('coverage-ignored-branch.lcov');
+  const env = { ...process.env };
+  delete env.NODE_TEST_CONTEXT;
+  const args = [
+    '--test',
+    '--experimental-test-coverage',
+    '--test-coverage-include=coverage-ignored-branch.js',
+    '--test-reporter',
+    'lcov',
+    '--test-reporter-destination',
+    destination,
+    fixture,
+  ];
+  const result = spawnSync(process.execPath, args, {
+    cwd: fixtures.path('test-runner'),
+    env,
+  });
+
+  assert.strictEqual(result.stderr.toString(), '');
+  assert.strictEqual(result.status, 0);
+
+  const report = readFileSync(destination, 'utf8');
+  assert.match(report, /^BRF:3$/m);
+  assert.match(report, /^BRH:3$/m);
+  assert.doesNotMatch(report, /^BRDA:.*,0$/m);
+  assert.doesNotMatch(report, /^DA:8,/m);
+});
+
 test('coverage with ESM hook - source irrelevant', skipIfNoInspector, () => {
   let report = [
     '# start of coverage report',