From bf9854ff45fc2284ae9a40570679b6087f57d217 Mon Sep 17 00:00:00 2001
From: marco-ippolito <marcoippolito54@gmail.com>
Date: Thu, 4 Jan 2024 13:16:45 +0100
Subject: [PATCH] test_runner: create flag --check-coverage to enforce code
 coverage

---
 doc/api/cli.md                                | 17 +++++++++++++
 doc/api/test.md                               | 15 +++++++++++
 doc/node.1                                    |  7 ++++++
 lib/internal/test_runner/test.js              | 10 +++++++-
 lib/internal/test_runner/utils.js             | 10 ++++++++
 src/node_options.cc                           |  3 +++
 src/node_options.h                            |  1 +
 .../test-runner/output/coverage_check.js      | 25 +++++++++++++++++++
 .../output/coverage_check.snapshot            | 23 +++++++++++++++++
 .../output/coverage_insufficient.js           | 25 +++++++++++++++++++
 .../output/coverage_insufficient.snapshot     | 24 ++++++++++++++++++
 11 files changed, 159 insertions(+), 1 deletion(-)
 create mode 100644 test/fixtures/test-runner/output/coverage_check.js
 create mode 100644 test/fixtures/test-runner/output/coverage_check.snapshot
 create mode 100644 test/fixtures/test-runner/output/coverage_insufficient.js
 create mode 100644 test/fixtures/test-runner/output/coverage_insufficient.snapshot

diff --git a/doc/api/cli.md b/doc/api/cli.md
index 072b3b8ead55b8..e83fe2a82b2249 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -887,11 +887,28 @@ changes:
     description: This option can be used with `--test`.
 -->
 
+> Stability: 1 - Experimental
+
 When used in conjunction with the `node:test` module, a code coverage report is
 generated as part of the test runner output. If no tests are run, a coverage
 report is not generated. See the documentation on
 [collecting code coverage from tests][] for more details.
 
+### `--check-coverage=coverage_threshold`
+
+<!-- YAML
+added:
+  - REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+The `--check-coverage` CLI flag, used in conjunction with the `--experimental-test-coverage` commands,
+enforce a specific test coverage threshold.
+It is expressed as a numerical value between `0` and `100`,
+representing the percentage (e.g., 80 for 80% coverage).
+If the coverage falls below the threshold, the test will result in a failure.
+
 ### `--experimental-vm-modules`
 
 <!-- YAML
diff --git a/doc/api/test.md b/doc/api/test.md
index 6d4725ba93c9fb..2c66206ebab462 100644
--- a/doc/api/test.md
+++ b/doc/api/test.md
@@ -403,6 +403,20 @@ if (anAlwaysFalseCondition) {
 }
 ```
 
+By using the CLI flag [`--check-coverage=coverage_threshold`][]
+in conjunction with the `--experimental-test-coverage` command,
+it is possible to enforce a specific test coverage threshold.
+When enabled, it evaluates the test coverage achieved during
+the execution of tests and determines whether it meets
+or exceeds the specified coverage threshold.
+If the coverage falls below the threshold,
+the command will result in a failure,
+indicating that the desired test coverage has not been reached.
+
+```bash
+node --test --experimental-test-coverage --check-coverage=100
+```
+
 ### Coverage reporters
 
 The tap and spec reporters will print a summary of the coverage statistics.
@@ -2966,6 +2980,7 @@ added:
 
 [TAP]: https://testanything.org/
 [TTY]: tty.md
+[`--check-coverage=coverage_threshold`]: cli.md#--check-coveragecoverage_threshold
 [`--experimental-test-coverage`]: cli.md#--experimental-test-coverage
 [`--import`]: cli.md#--importmodule
 [`--test-concurrency`]: cli.md#--test-concurrency
diff --git a/doc/node.1 b/doc/node.1
index 2966c14e1c3f5e..ba70fa247b86fa 100644
--- a/doc/node.1
+++ b/doc/node.1
@@ -91,6 +91,13 @@ Allow spawning process when using the permission model.
 .It Fl -allow-worker
 Allow creating worker threads when using the permission model.
 .
+.It Fl -check-coverage
+Enforce a minimum test coverage threshold (0 to 100)
+when used with the
+.Fl -experimental-test-coverage
+flag.
+The command fails if coverage falls below the specified threshold.
+.
 .It Fl -completion-bash
 Print source-able bash completion script for Node.js.
 .
diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index 19ae283ed9ad78..575b9c4f771a45 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -10,6 +10,7 @@ const {
   FunctionPrototype,
   MathMax,
   Number,
+  NumberPrototypeToFixed,
   ObjectSeal,
   PromisePrototypeThen,
   PromiseResolve,
@@ -58,6 +59,7 @@ const {
 const { setTimeout } = require('timers');
 const { TIMEOUT_MAX } = require('internal/timers');
 const { availableParallelism } = require('os');
+const { exitCodes: { kGenericUserError } } = internalBinding('errors');
 const { bigint: hrtime } = process.hrtime;
 const kCallbackAndPromisePresent = 'callbackAndPromisePresent';
 const kCancelledByParent = 'cancelledByParent';
@@ -75,7 +77,7 @@ const kHookNames = ObjectSeal(['before', 'after', 'beforeEach', 'afterEach']);
 const kUnwrapErrors = new SafeSet()
   .add(kTestCodeFailure).add(kHookFailure)
   .add('uncaughtException').add('unhandledRejection');
-const { testNamePatterns, testOnlyFlag } = parseCommandLine();
+const { testNamePatterns, testOnlyFlag, coverageThreshold } = parseCommandLine();
 let kResistStopPropagation;
 
 function stopTest(timeout, signal) {
@@ -753,6 +755,12 @@ class Test extends AsyncResource {
       reporter.diagnostic(nesting, loc, `duration_ms ${this.duration()}`);
 
       if (coverage) {
+        const actualCoverage = coverage.totals.coveredLinePercent;
+        if (actualCoverage < coverageThreshold) {
+          const msg = `ERROR: Global coverage (${NumberPrototypeToFixed(actualCoverage, 2)}%) does not meet expected threshold (${coverageThreshold}%)\n`;
+          reporter.stderr(loc, msg);
+          process.exitCode = kGenericUserError;
+        }
         reporter.coverage(nesting, loc, coverage);
       }
 
diff --git a/lib/internal/test_runner/utils.js b/lib/internal/test_runner/utils.js
index 184d44dce6c162..f3a5fa99726053 100644
--- a/lib/internal/test_runner/utils.js
+++ b/lib/internal/test_runner/utils.js
@@ -193,6 +193,15 @@ function parseCommandLine() {
 
   const isTestRunner = getOptionValue('--test');
   const coverage = getOptionValue('--experimental-test-coverage');
+  const coverageThreshold = getOptionValue('--check-coverage');
+  if (coverageThreshold < 0 || coverageThreshold > 100) {
+    throw new ERR_INVALID_ARG_VALUE(
+      '--check-coverage',
+      coverageThreshold,
+      'must be a value between 0 and 100',
+    );
+  }
+
   const isChildProcess = process.env.NODE_TEST_CONTEXT === 'child';
   const isChildProcessV8 = process.env.NODE_TEST_CONTEXT === 'child-v8';
   let destinations;
@@ -244,6 +253,7 @@ function parseCommandLine() {
     __proto__: null,
     isTestRunner,
     coverage,
+    coverageThreshold,
     testOnlyFlag,
     testNamePatterns,
     reporters,
diff --git a/src/node_options.cc b/src/node_options.cc
index 7b5152172c5ce7..f637f7391277f9 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -622,6 +622,9 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--experimental-test-coverage",
             "enable code coverage in the test runner",
             &EnvironmentOptions::test_runner_coverage);
+  AddOption("--check-coverage",
+            "check that coverage falls within the threshold provided",
+            &EnvironmentOptions::test_runner_check_coverage);
   AddOption("--test-name-pattern",
             "run tests whose name matches this regular expression",
             &EnvironmentOptions::test_name_pattern);
diff --git a/src/node_options.h b/src/node_options.h
index 915151b7dc2904..68a7717d82acb8 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -166,6 +166,7 @@ class EnvironmentOptions : public Options {
   uint64_t test_runner_concurrency = 0;
   uint64_t test_runner_timeout = 0;
   bool test_runner_coverage = false;
+  uint64_t test_runner_check_coverage = 0;
   std::vector<std::string> test_name_pattern;
   std::vector<std::string> test_reporter;
   std::vector<std::string> test_reporter_destination;
diff --git a/test/fixtures/test-runner/output/coverage_check.js b/test/fixtures/test-runner/output/coverage_check.js
new file mode 100644
index 00000000000000..291992172a7bb4
--- /dev/null
+++ b/test/fixtures/test-runner/output/coverage_check.js
@@ -0,0 +1,25 @@
+// Flags: --expose-internals --experimental-test-coverage --check-coverage=100
+
+'use strict';
+require('../../../common');
+const { TestCoverage } = require('internal/test_runner/coverage');
+const { test, mock } = require('node:test');
+
+mock.method(TestCoverage.prototype, 'summary', () => {
+    return {
+        files: [],
+        totals: {
+            totalLineCount: 100,
+            totalBranchCount: 100,
+            totalFunctionCount: 100,
+            coveredLineCount: 100,
+            coveredBranchCount: 100,
+            coveredFunctionCount: 100,
+            coveredLinePercent: 100,
+            coveredBranchPercent: 100,
+            coveredFunctionPercent: 100
+        }
+    }
+});
+
+test('ok');
diff --git a/test/fixtures/test-runner/output/coverage_check.snapshot b/test/fixtures/test-runner/output/coverage_check.snapshot
new file mode 100644
index 00000000000000..615d058b6c188d
--- /dev/null
+++ b/test/fixtures/test-runner/output/coverage_check.snapshot
@@ -0,0 +1,23 @@
+TAP version 13
+# Subtest: ok
+ok 1 - ok
+  ---
+  duration_ms: 0.423333
+  ...
+1..1
+# tests 1
+# suites 0
+# pass 1
+# fail 0
+# cancelled 0
+# skipped 0
+# todo 0
+# duration_ms 5.332083
+# start of coverage report
+# -----------------------------------------------------
+# file | line % | branch % | funcs % | uncovered lines
+# -----------------------------------------------------
+# -----------------------------------------------------
+# all… | 100.00 |   100.00 |  100.00 |
+# -----------------------------------------------------
+# end of coverage report
diff --git a/test/fixtures/test-runner/output/coverage_insufficient.js b/test/fixtures/test-runner/output/coverage_insufficient.js
new file mode 100644
index 00000000000000..212374e8dad78f
--- /dev/null
+++ b/test/fixtures/test-runner/output/coverage_insufficient.js
@@ -0,0 +1,25 @@
+// Flags: --expose-internals --experimental-test-coverage --check-coverage=100
+
+'use strict';
+require('../../../common');
+const { TestCoverage } = require('internal/test_runner/coverage');
+const { test, mock } = require('node:test');
+
+mock.method(TestCoverage.prototype, 'summary', () => {
+    return {
+        files: [],
+        totals: {
+            totalLineCount: 0,
+            totalBranchCount: 0,
+            totalFunctionCount: 0,
+            coveredLineCount: 0,
+            coveredBranchCount: 0,
+            coveredFunctionCount: 0,
+            coveredLinePercent: 0,
+            coveredBranchPercent: 0,
+            coveredFunctionPercent: 0
+        }
+    }
+});
+
+test('ok');
diff --git a/test/fixtures/test-runner/output/coverage_insufficient.snapshot b/test/fixtures/test-runner/output/coverage_insufficient.snapshot
new file mode 100644
index 00000000000000..dcbd39279ab97e
--- /dev/null
+++ b/test/fixtures/test-runner/output/coverage_insufficient.snapshot
@@ -0,0 +1,24 @@
+TAP version 13
+# Subtest: ok
+ok 1 - ok
+  ---
+  duration_ms: 0.845333
+  ...
+1..1
+# tests 1
+# suites 0
+# pass 1
+# fail 0
+# cancelled 0
+# skipped 0
+# todo 0
+# duration_ms 5.3
+# ERROR: Global coverage (0.00%) does not meet expected threshold (100%)
+# start of coverage report
+# -----------------------------------------------------
+# file | line % | branch % | funcs % | uncovered lines
+# -----------------------------------------------------
+# -----------------------------------------------------
+# all… |   0.00 |     0.00 |    0.00 |
+# -----------------------------------------------------
+# end of coverage report