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A JavaScript code coverage tool to generate native V8 reports or Istanbul reports.
- Usage
- Options
- Available Reports
- Compare Reports
- Collecting Istanbul Coverage Data
- Collecting V8 Coverage Data
- Filtering Results
- Resolve
sourcePath
for the Source Files - Adding Empty Coverage for Untested Files
- onEnd Hook
- Ignoring Uncovered Codes
- Multiprocessing Support
- Command Line
- Config File
- Merge Coverage Reports
- Common issues
- Debug for Coverage and Sourcemap
- Integration with Any Testing Framework
- Integration Examples
- Contributing
- Changelog
- Thanks
It's recommended to use Node.js 20+.
- Install
npm install monocart-coverage-reports
- API
const MCR = require('monocart-coverage-reports');
const mcr = MCR({
name: 'My Coverage Report - 2024-02-28',
outputDir: './coverage-reports',
reports: ["v8", "console-details"],
cleanCache: true
});
await mcr.add(coverageData);
await mcr.generate();
Using import
and load options from config file
import { CoverageReport } from 'monocart-coverage-reports';
const mcr = new CoverageReport();
await mcr.loadConfig();
For more information, see Multiprocessing Support
- CLI
mcr node my-app.js -r v8,console-details
For more information, see Command Line
- Default options: lib/default/options.js
- Options declaration see
CoverageReportOptions
lib/index.d.ts - Config file
V8 build-in reports (V8 data only):
v8
v8-json
- Save
CoverageResults
to a json file (defaults tocoverage-report.json
). - Shows native V8 code coverage with VSCode extension: Monocart Coverage for VSCode
- Save
Istanbul build-in reports (both V8 and Istanbul data):
clover
cobertura
html
html-spa
json
json-summary
lcov
lcovonly
none
teamcity
text
text-lcov
text-summary
Other build-in reports (both V8 and Istanbul data):
-
codecov
Save coverage data to a json file with Codecov format (defaults tocodecov.json
), see example. -
codacy
Save coverage data to a json file with Codacy API format (defaults tocodacy.json
). -
console-summary
shows coverage summary in the console.
console-details
Show coverage details in the console. Liketext
, but for V8. For Github actions, we can enforce color with env:FORCE_COLOR: true
.
markdown-summary
Save coverage summary to a markdown file (defaults tocoverage-summary.md
). For Github actions, we can show the markdown content to a job summary
cat path-to/coverage-summary.md >> $GITHUB_STEP_SUMMARY
-
markdown-details
Save coverage details to a markdown file (defaults tocoverage-details.md
).- Preview in runs
-
raw
only keep all original data, which can be used for other reports input withinputDir
. see Merge Coverage Reports -
Custom Reporter
{ reports: [ [path.resolve('./test/custom-istanbul-reporter.js'), { type: 'istanbul', file: 'custom-istanbul-coverage.text' }], [path.resolve('./test/custom-v8-reporter.js'), { type: 'v8', outputFile: 'custom-v8-coverage.json' }], [path.resolve('./test/custom-v8-reporter.mjs'), { type: 'both' }] ] }
- Istanbul custom reporter
example: ./test/custom-istanbul-reporter.js, see istanbul built-in reporters' implementation for reference.
- V8 custom reporter
example: ./test/custom-v8-reporter.js
const MCR = require('monocart-coverage-reports');
const coverageOptions = {
outputDir: './coverage-reports',
reports: [
// build-in reports
['console-summary'],
['v8'],
['html', {
subdir: 'istanbul'
}],
['json', {
file: 'my-json-file.json'
}],
'lcovonly',
// custom reports
// Specify reporter name with the NPM package
["custom-reporter-1"],
["custom-reporter-2", {
type: "istanbul",
key: "value"
}],
// Specify reporter name with local path
['/absolute/path/to/custom-reporter.js']
]
}
const mcr = MCR(coverageOptions);
If the V8 data format is used for Istanbul reports, it will be automatically converted from V8 to Istanbul.
Istanbul | V8 | V8 to Istanbul | |
---|---|---|---|
Coverage data | Istanbul (Object) | V8 (Array) | V8 (Array) |
Output | Istanbul reports | V8 reports | Istanbul reports |
- Bytes | ❌ | ✅ | ❌ |
- Statements | ✅ | ✅ | ✅ |
- Branches | ✅ | ✅ | ✅ |
- Functions | ✅ | ✅ | ✅ |
- Lines | ✅ | ✅ | ✅ |
- Execution counts | ✅ | ✅ | ✅ |
CSS coverage | ❌ | ✅ | ✅ |
Minified code | ❌ | ✅ | ❌ |
-
Before coverage collection: Instrumenting source code with Istanbul
- webpack with babel loader: babel-plugin-istanbul, see example: webpack.config-istanbul.js
- CLI: nyc instrument or API: istanbul-lib-instrument
- vite: vite-plugin-istanbul
- rollup: rollup-plugin-istanbul
- swc: swc-plugin-coverage-instrument
-
Browser
- Collecting coverage data from
window.__coverage__
, example: test-istanbul.js
- Collecting coverage data from
-
Node.js
- Collecting coverage data from
global.__coverage__
- Collecting coverage data from
-
CDP
getIstanbulCoverage()
seeCDPClient
API
-
Before coverage collection: Enabling
sourcemap
for source code- webpack:
devtool: source-map
andmode: development
, example webpack.config-v8.js - rollup:
sourcemap: true
andtreeshake: false
- esbuild:
sourcemap: true
,treeShaking: false
andminify: false
- vite:
sourcemap: true
andminify: false
- webpack:
-
Browser (Chromium-based Only)
-
Node.js
-
CDP
await Promise.all([
page.coverage.startJSCoverage({
// reportAnonymousScripts: true,
resetOnNavigation: false
}),
page.coverage.startCSSCoverage({
// Note, anonymous styles (without sourceURLs) are not supported, alternatively, you can use CDPClient
resetOnNavigation: false
})
]);
await page.goto("your page url");
const [jsCoverage, cssCoverage] = await Promise.all([
page.coverage.stopJSCoverage(),
page.coverage.stopCSSCoverage()
]);
const coverageData = [... jsCoverage, ... cssCoverage];
Collect coverage with @playwright/test
Automatic fixtures
, see example: fixtures.ts
For more examples, see ./test/test-v8.js, and anonymous, css
await Promise.all([
page.coverage.startJSCoverage({
// reportAnonymousScripts: true,
resetOnNavigation: false,
// provide raw v8 coverage data
includeRawScriptCoverage: true
}),
page.coverage.startCSSCoverage({
resetOnNavigation: false
})
]);
await page.goto("your page url");
const [jsCoverage, cssCoverage] = await Promise.all([
page.coverage.stopJSCoverage(),
page.coverage.stopCSSCoverage()
]);
// to raw V8 script coverage
const coverageData = [... jsCoverage.map((it) => {
return {
source: it.text,
... it.rawScriptCoverage
};
}), ... cssCoverage];
Example: ./test/test-puppeteer.js
Possible solutions:
-
NODE_V8_COVERAGE=
dir
- Sets Node.js env
NODE_V8_COVERAGE
=dir
before the program running, the coverage data will be saved to thedir
after the program exits gracefully. - Read the JSON file(s) from the
dir
and generate coverage report. - Example:
cross-env NODE_V8_COVERAGE=
.temp/v8-coverage-env
node ./test/test-node-env.js && node ./test/generate-report.js - Sets Node.js env
-
V8 API + NODE_V8_COVERAGE
- Writing the coverage started by NODE_V8_COVERAGE to disk on demand with
v8.takeCoverage()
, it does not require waiting until the program exits gracefully. - Example:
cross-env NODE_V8_COVERAGE=
.temp/v8-coverage-api
node ./test/test-node-api.js - Writing the coverage started by NODE_V8_COVERAGE to disk on demand with
-
Inspector API
- Connecting to the V8 inspector and enable V8 coverage.
- Taking coverage data and adding it to the report.
- Example:
- vm Example (scriptOffset):
-
CDP API
- Enabling Node Debugging.
- Collecting coverage data with CDP API.
- Example:
node --inspect=9229 ./test/test-node-cdp.js
-
Node Debugging + CDP + NODE_V8_COVERAGE + V8 API
- When the program starts a server, it will not exit on its own, thus requiring a manual invocation of the
v8.takeCoverage()
interface to manually collect coverage data. Remote invocation of thev8.takeCoverage()
interface can be accomplished through theRuntime.evaluate
of the CDP. - Example for koa web server:
- When the program starts a server, it will not exit on its own, thus requiring a manual invocation of the
-
Child Process + NODE_V8_COVERAGE
- see Command Line
CDPClient
available APIs
startJSCoverage: () => Promise<void>;
stopJSCoverage: () => Promise<V8CoverageEntry[]>;
startCSSCoverage: () => Promise<void>;
stopCSSCoverage: () => Promise<V8CoverageEntry[]>;
/** start both js and css coverage */
startCoverage: () => Promise<void>;
/** stop and return both js and css coverage */
stopCoverage: () => Promise<V8CoverageEntry[]>;
/** write the coverage started by NODE_V8_COVERAGE to disk on demand, returns v8 coverage dir */
writeCoverage: () => Promise<string>;
/** get istanbul coverage data */
getIstanbulCoverage: (coverageKey?: string) => Promise<any>;
- Work with node debugger port
--inspect=9229
or browser debugging port--remote-debugging-port=9229
const MCR = require('monocart-coverage-reports');
const client = await MCR.CDPClient({
port: 9229
});
await client.startJSCoverage();
// run your test here
const coverageData = await client.stopJSCoverage();
- Work with Playwright CDPSession
const { chromium } = require('playwright');
const MCR = require('monocart-coverage-reports');
const browser = await chromium.launch();
const page = await browser.newPage();
const session = await page.context().newCDPSession(page);
const client = await MCR.CDPClient({
session
});
// both js and css coverage
await client.startCoverage();
// run your test page here
await page.goto("your page url");
const coverageData = await client.stopCoverage();
- Work with Puppeteer CDPSession
const puppeteer = require('puppeteer');
const MCR = require('monocart-coverage-reports');
const browser = await puppeteer.launch({});
const page = await browser.newPage();
const session = await page.target().createCDPSession();
const client = await MCR.CDPClient({
session
});
// both js and css coverage
await client.startCoverage();
// run your test page here
await page.goto("your page url");
const coverageData = await client.stopCoverage();
- Work with Selenium Webdriver WebSocket (Chrome/Edge Browser)
const { Builder, Browser } = require('selenium-webdriver');
const MCR = require('monocart-coverage-reports');
const driver = await new Builder().forBrowser(Browser.CHROME).build();
const pageCdpConnection = await driver.createCDPConnection('page');
const session = new MCR.WSSession(pageCdpConnection._wsConnection);
const client = await MCR.CDPClient({
session
})
- JavaScript code coverage in V8
- Playwright Coverage Class
- Puppeteer Coverage Class
- DevTools Protocol for Coverage see ScriptCoverage and v8-coverage
// Coverage data for a source range.
export interface CoverageRange {
// JavaScript script source offset for the range start.
startOffset: integer;
// JavaScript script source offset for the range end.
endOffset: integer;
// Collected execution count of the source range.
count: integer;
}
// Coverage data for a JavaScript function.
/**
* @functionName can be an empty string.
* @ranges is always non-empty. The first range is called the "root range".
* @isBlockCoverage indicates if the function has block coverage information.
If this is false, it usually means that the functions was never called.
It seems to be equivalent to ranges.length === 1 && ranges[0].count === 0.
*/
export interface FunctionCoverage {
// JavaScript function name.
functionName: string;
// Source ranges inside the function with coverage data.
ranges: CoverageRange[];
// Whether coverage data for this function has block granularity.
isBlockCoverage: boolean;
}
// Coverage data for a JavaScript script.
export interface ScriptCoverage {
// JavaScript script id.
scriptId: Runtime.ScriptId;
// JavaScript script name or url.
url: string;
// Functions contained in the script that has coverage data.
functions: FunctionCoverage[];
}
export type V8CoverageData = ScriptCoverage[];
JavaScript Runtime | V8 Coverage | |
---|---|---|
Chrome (65%) | ✅ | Chromium-based |
Safari (18%) | ❌ | |
Edge (5%) | ✅ | Chromium-based |
Firefox (2%) | ❌ | |
Node.js | ✅ | |
Deno | ❌ | issue |
Bun | ❌ |
When V8 coverage data collected, it actually contains the data of all entry files, for example:
- dist/main.js
- dist/vendor.js
- dist/something-else.js
We can use entryFilter
to filter the entry files. For example, we should remove vendor.js
and something-else.js
if they are not in our coverage scope.
- dist/main.js
When inline or linked sourcemap exists to the entry file, the source files will be extracted from the sourcemap for the entry file, and the entry file will be removed if logging
is not debug
.
- src/index.js
- src/components/app.js
- node_modules/dependency/dist/dependency.js
We can use sourceFilter
to filter the source files. For example, we should remove dependency.js
if it is not in our coverage scope.
- src/index.js
- src/components/app.js
For example:
const coverageOptions = {
entryFilter: (entry) => entry.url.indexOf("main.js") !== -1,
sourceFilter: (sourcePath) => sourcePath.search(/src\//) !== -1
};
Or using minimatch
pattern:
const coverageOptions = {
entryFilter: "**/main.js",
sourceFilter: "**/src/**"
};
Support multiple patterns:
const coverageOptions = {
entryFilter: {
'**/node_modules/**': false,
'**/vendor.js': false,
'**/src/**': true
},
sourceFilter: {
'**/node_modules/**': false,
'**/**': true
}
};
As CLI args (JSON-like string. Added in: v2.8):
mcr --sourceFilter "{'**/node_modules/**':false,'**/**':true}"
Note, those patterns will be transformed to a function, and the order of the patterns will impact the results:
const coverageOptions = {
entryFilter: (entry) => {
if (minimatch(entry.url, '**/node_modules/**')) { return false; }
if (minimatch(entry.url, '**/vendor.js')) { return false; }
if (minimatch(entry.url, '**/src/**')) { return true; }
return false; // else unmatched
}
};
If you don't want to define both entryFilter
and sourceFilter
, you can use filter
instead. (Added in: v2.8)
const coverageOptions = {
// combined patterns
filter: {
'**/node_modules/**': false,
'**/vendor.js': false,
'**/src/**': true
'**/**': true
}
};
If the source file comes from the sourcemap, then its path is a virtual path. Using the sourcePath
option to resolve a custom path.
For example, we have tested multiple dist files, which contain some common files. We hope to merge the coverage of the same files, so we need to unify the sourcePath
in order to be able to merge the coverage data.
const coverageOptions = {
sourcePath: (filePath) => {
// Remove the virtual prefix
const list = ['my-dist-file1/', 'my-dist-file2/'];
for (const str of list) {
if (filePath.startsWith(str)) {
return filePath.slice(str.length);
}
}
return filePath;
}
};
It also supports simple key/value replacement:
const coverageOptions = {
sourcePath: {
'my-dist-file1/': '',
'my-dist-file2/': ''
}
};
Normalize the full path of the file:
const path = require("path")
// MCR coverage options
const coverageOptions = {
sourcePath: (filePath, info)=> {
if (!filePath.includes('/') && info.distFile) {
return `${path.dirname(info.distFile)}/${filePath}`;
}
return filePath;
}
}
By default the untested files will not be included in the coverage report, we can add empty coverage for untested files with option all
, the untested files will show 0% coverage.
const coverageOptions = {
all: './src',
// or multiple dirs
all: ['./src', './lib'],
};
The untested files will apply to the sourceFilter
. And it also supports additional filter
(return the file type for js or css coverage):
const coverageOptions = {
all: {
dir: ['./src'],
filter: {
// exclude files
'**/ignored-*.js': false,
'**/*.html': false,
// empty css coverage
'**/*.scss': "css",
'**/*': true
}
}
};
We can also compile these untested files, such as .ts, .jsx, or .vue, etc., so that they can be analyzed by the default AST parser, thus get more coverage metric data.
const path = require("path");
const swc = require("@swc/core");
const coverageOptions = {
all: {
dir: ['./src'],
transformer: async (entry) => {
const { code, map } = await swc.transform(entry.source, {
filename: path.basename(entry.url),
sourceMaps: true,
isModule: true,
jsc: {
parser: {
syntax: "typescript",
jsx: true
},
transform: {}
}
});
entry.source = code;
entry.sourceMap = JSON.parse(map);
}
}
};
For example, checking thresholds:
const EC = require('eight-colors');
const coverageOptions = {
name: 'My Coverage Report',
outputDir: './coverage-reports',
onEnd: (coverageResults) => {
const thresholds = {
bytes: 80,
lines: 60
};
console.log('check thresholds ...', thresholds);
const errors = [];
const { summary } = coverageResults;
Object.keys(thresholds).forEach((k) => {
const pct = summary[k].pct;
if (pct < thresholds[k]) {
errors.push(`Coverage threshold for ${k} (${pct} %) not met: ${thresholds[k]} %`);
}
});
if (errors.length) {
const errMsg = errors.join('\n');
console.log(EC.red(errMsg));
// throw new Error(errMsg);
// process.exit(1);
}
}
}
To ignore codes, use the special comment which starts with v8 ignore
:
- Ignoring all until stop
/* v8 ignore start */
function uncovered() {
}
/* v8 ignore stop */
- Ignoring the next line or next N lines
/* v8 ignore next */
const os = platform === 'wind32' ? 'Windows' : 'Other';
const os = platform === 'wind32' ? 'Windows' /* v8 ignore next */ : 'Other';
// v8 ignore next 3
if (platform === 'linux') {
console.log('hello linux');
}
The data will be added to
[outputDir]/.cache
, After the generation of the report, this data will be removed unless debugging has been enabled or a raw report has been used, see Debug for Coverage and Sourcemap
- Main process, before the start of testing
const MCR = require('monocart-coverage-reports');
const coverageOptions = require('path-to/same-options.js');
const mcr = MCR(coverageOptions);
// clean previous cache before the start of testing
// unless the running environment is new and no cache
mcr.cleanCache();
- Sub process 1, testing stage 1
const MCR = require('monocart-coverage-reports');
const coverageOptions = require('path-to/same-options.js');
const mcr = MCR(coverageOptions);
await mcr.add(coverageData1);
- Sub process 2, testing stage 2
const MCR = require('monocart-coverage-reports');
const coverageOptions = require('path-to/same-options.js');
const mcr = MCR(coverageOptions);
await mcr.add(coverageData2);
- Main process, after the completion of testing
// generate coverage reports after the completion of testing
const MCR = require('monocart-coverage-reports');
const coverageOptions = require('path-to/same-options.js');
const mcr = MCR(coverageOptions);
await mcr.generate();
The CLI will run the program as a child process with
NODE_V8_COVERAGE=dir
until it exits gracefully, and generate the coverage report with the coverage data from thedir
.
- Installing globally
npm i monocart-coverage-reports -g
mcr node ./test/specs/node.test.js -r v8,console-details --lcov
- Locally in your project
npm i monocart-coverage-reports
npx mcr node ./test/specs/node.test.js -r v8,console-details --lcov
-
CLI Options see all options with running
mcr
ormcr --help
-
Use
--
to separate sub CLI args
mcr -c mcr.config.js -- sub-cli -c sub-cli.config.js
- Examples
Loading config file by priority:
- Custom config file:
- CLI:
mcr --config <my-config-file-path>
- API:
await mcr.loadConfig("my-config-file-path")
- CLI:
mcr.config.js
mcr.config.cjs
mcr.config.mjs
mcr.config.json
- json formatmcr.config.ts
(requires preloading the ts execution module)
The following usage scenarios may require merging coverage reports:
- When the code is executed in different environments, like Node.js
server side
and browserclient side
(Next.js
for instance). Each environment may generate its own coverage report. Merging them can give a more comprehensive view of the test coverage. - When the code is subjected to different kinds of testing. For example,
unit tests
withJest
might cover certain parts of the code, whileend-to-end tests
withPlaywright
might cover other parts. Merging these different coverage reports can provide a holistic view of what code has been tested. - When tests are run on different machines or containers, each might produce its own coverage report. Merging these can give a complete picture of the test coverage across all machines or shards.
- The
MCR
will automatically merge all the added coverage data when executinggenerate()
. And it supports adding coverage data asynchronously across processes, see Multiprocessing Support - For
Next.js
, it can actually add coverage data including both server side and client side before executinggenerate()
, see example nextjs-with-playwright - Using
Codecov
, a popular online code coverage service, which supports automatic merging of reports. Please use reportcodecov
, it will generate report filecodecov.json
. If multiplecodecov.json
files are generated, upload all these files, they will be automatically merged. see Codecov and merging reports
If the reports cannot be merged automatically, then here is how to manually merge the reports.
First, using the raw
report to export the original coverage data to the specified directory.
- For example, we have
raw
coverage data fromunit test
, which is output to./coverage-reports/unit/raw
. Unit test examples:Jest
+ jest-monocart-coverageVitest
+ vitest-monocart-coverage
const coverageOptions = {
name: 'My Unit Test Coverage Report',
outputDir: "./coverage-reports/unit",
reports: [
['raw', {
// relative path will be "./coverage-reports/unit/raw"
// defaults to raw
outputDir: "raw"
}],
['v8'],
['console-details']
]
};
-
We also have
raw
coverage data frome2e test
, which is output to./coverage-reports/e2e/raw
. E2E test examples:Playwright
+ monocart-reporter with coverage APIPlaywright
+MCR
, see playwright-coverage- see more Integration Examples
-
Then create a script
merge-coverage.js
to generate a merged report with optioninputDir
.
// merge-coverage.js
const fs = require('fs');
const { CoverageReport } = require('monocart-coverage-reports');
const inputDir = [
'./coverage-reports/unit/raw',
'./coverage-reports/e2e/raw'
];
const coverageOptions = {
name: 'My Merged Coverage Report',
inputDir,
outputDir: './coverage-reports/merged',
// filter for both unit and e2e
entryFilter: {
'**/node_modules/**': false,
'**/*': true
},
sourceFilter: {
'**/node_modules/**': false,
'**/src/**': true
},
sourcePath: (filePath, info) => {
// Unify the file path for the same files
// For example, the file index.js has different paths:
// unit: unit-dist/src/index.js
// e2e: e2e-dist/src/index.js
// return filePath.replace("unit-dist/", "").replace("e2e-dist/", "")
return filePath;
},
reports: [
['v8'],
['console-details']
],
onEnd: () => {
// remove the raw files if it useless
// inputDir.forEach((p) => {
// fs.rmSync(p, {
// recursive: true,
// force: true
// });
// });
}
};
await new CoverageReport(coverageOptions).generate();
- Running script
node path/to/merge-coverage.js
after all the tests are completed. All the command scripts are probably like following:
{
"scripts": {
"test:unit": "jest",
"test:e2e": "playwright test",
"merge-coverage": "node path/to/merge-coverage.js",
"test": "npm run test:unit && npm run test:e2e && npm run merge-coverage"
}
}
see example: merge-code-coverage
In most cases, it happens when the coverage of the generated code is converted to the coverage of the original code through a sourcemap. In other words, it's an issue with the sourcemap. Most of the time, we can solve this by setting minify
to false
in the configuration of build tools. Let's take a look at an example:
const a = tf ? 'true' : 'false';
^ ^ ^
m1 p m2
In the generated code, there is a position p
, and we need to find out its corresponding position in the original code. Unfortunately, there is no matched mapping for the position p
. Instead, it has two adjacent upstream and downstream mappings m1
and m2
, so, the original position of p
that we are looking for, might not be able to be precisely located. Especially, the generated code is different from the original code, such as the code was minified, compressed or converted, it is difficult to find the exact original position without matched mapping.
- Further understanding of sourcemap, try Debug for Coverage and Sourcemap
How MCR
Works:
- 1, Trying to fix the original position with string comparison and
diff-sequences
. However, for non-JS code, such as Vue template, JSX, etc., it might be hard to find a perfect solution. - 2, Finding all functions, statements and branches by parsing the source code AST. (There is a small issue is the V8 cannot provide effective branch coverage information for
AssignmentPattern
)
It happens during the parsing of the source code into AST, if the source code is not in the standard ECMAScript. For example ts
, jsx
and so on. There is a option to fix it, which is to manually compile the source code for these files.
import * as fs from "fs";
import * as path from "path";
import { fileURLToPath } from "url";
import * as TsNode from 'ts-node';
const coverageOptions = {
onEntry: async (entry) => {
const filePath = fileURLToPath(entry.url)
const originalSource = fs.readFileSync(filePath).toString("utf-8");
const fileName = path.basename(filePath);
const tn = TsNode.create({});
const source = tn.compile(originalSource, fileName);
entry.fake = false;
entry.source = source;
}
}
When there are a lot of raw v8 coverage files to process, it may cause OOM. We can try the following Node.js options:
- run: npm run test:coverage
env:
NODE_OPTIONS: --max-old-space-size=8192
Sometimes, the coverage is not what we expect. The next step is to figure out why, and we can easily find out the answer step by step through debugging.
- Start debugging for v8 report with option
logging: 'debug'
const coverageOptions = {
logging: 'debug',
reports: [
['v8'],
['console-details']
]
};
When logging
is debug
, the raw report data will be preserved in [outputDir]/.cache
or [outputDir]/raw
if raw
report is used. And the dist file will be preserved in the V8 list, and by opening the browser's devtool, it makes data verification visualization effortless.
- Check sourcemap with Source Map Visualization
- Show time logs with env
MCR_LOG_TIME
process.env.MCR_LOG_TIME = true
- API
- Collecting coverage data when any stage of the test is completed, and adding the coverage data to the coverage reporter.
await mcr.add(coverageData)
- Generating the coverage reports after the completion of all tests.
await mcr.generate()
- see Multiprocessing Support
- Collecting coverage data when any stage of the test is completed, and adding the coverage data to the coverage reporter.
- CLI
- Wrapping with any CLI.
mcr your-cli --your-arguments
- see Command line
- Wrapping with any CLI.
- playwright-coverage - Example for Playwright coverage reports
- playwright-bdd-coverage - Example for Playwright BDD coverage reports
- monocart-reporter - Playwright custom reporter, supports generating Code coverage report
- Coverage for component testing with
monocart-reporter
: - Coverage for Next.js, both server side and client side:
- Coverage for Remix:
- see Collecting V8 Coverage Data with Playwright
- c8 has integrated
MCR
as an experimental feature since v10.1.0
c8 --experimental-monocart --reporter=v8 --reporter=console-details node foo.js
- CodeceptJS is a BDD + AI testing framework for e2e testing, it has integrated
MCR
since v3.5.15, see plugins/coverage
- Monocart Coverage for VSCode - Shows native V8 code coverage in VSCode
- jest-monocart-coverage - Jest custom reporter for coverage reports
- merge-code-coverage - Example for merging code coverage (Jest unit + Playwright e2e sharding)
- vitest-monocart-coverage - Vitest custom provider module for coverage reports
- merge-code-coverage-vitest - Example for merging code coverage (Vitest unit + Playwright e2e sharding)
- node-monocart-coverage - Custom reporter for Node test runner for coverage
- jest-puppeteer-coverage - Example for Jest puppeteer coverage
- maplibre-gl-js - Example for Jest (unit) + Puppeteer (e2e) + Codecov
- see Collecting Raw V8 Coverage Data with Puppeteer
- cypress-monocart-coverage - Cypress plugin for coverage reports
- wdio-monocart-service - WebdriverIO service for coverage reports
- storybook-monocart-coverage - Example for Storybook V8 coverage reports
- testcafe-reporter-coverage - TestCafe custom reporter for coverage reports
- selenium-webdriver-coverage - Example for Selenium Webdriver V8 coverage reports
mcr mocha ./test/**/*.js
cross-env NODE_OPTIONS="--import tsx" npx mcr tsx ./src/example.ts
cross-env NODE_OPTIONS="--import tsx" npx mcr mocha ./test/**/*.ts
# Node.js v18.19.0 +
mcr --import tsx tsx ./src/example.ts
mcr --import tsx mocha ./test/**/*.ts
cross-env NODE_OPTIONS="--loader ts-node/esm --no-warnings" npx mcr ts-node ./src/example.ts
cross-env NODE_OPTIONS="--loader ts-node/esm --no-warnings" npx mcr mocha ./test/**/*.ts
mcr ava
- Supports native
codecov
built-in report (specification)
const coverageOptions = {
outputDir: "./coverage-reports",
reports: [
['codecov']
]
};
- Github actions:
- name: Codecov
uses: codecov/codecov-action@v4
with:
token: ${{ secrets.CODECOV_TOKEN }}
files: ./coverage-reports/codecov.json
- Using
lcov
report:
const coverageOptions = {
outputDir: "./coverage-reports",
lcov: true
};
- Github actions:
- name: Codacy Coverage Reporter
uses: codacy/codacy-coverage-reporter-action@v1
with:
project-token: ${{ secrets.CODACY_PROJECT_TOKEN }}
coverage-reports: ./docs/mcr/lcov.info
- Using
lcov
report:
const coverageOptions = {
outputDir: "./coverage-reports",
lcov: true
};
- Github actions:
- name: Coveralls
uses: coverallsapp/github-action@v2
with:
files: ./coverage-reports/lcov.info
- Using
lcov
report. Github actions example:
- name: Analyze with SonarCloud
uses: sonarsource/sonarcloud-github-action@master
env:
SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
with:
projectBaseDir: ./
args: >
-Dsonar.organization=cenfun
-Dsonar.projectKey=monocart-coverage-reports
-Dsonar.projectName=monocart-coverage-reports
-Dsonar.javascript.lcov.reportPaths=docs/mcr/lcov.info
-Dsonar.sources=lib
-Dsonar.tests=test
-Dsonar.exclusions=dist/*,packages/*
- Node.js 20+
- VSCode (extensions: eslint/stylelint/vue)
npm install
npx playwright install --with-deps
npm run build
npm run test
npm run dev
- Refreshing
eol=lf
for snapshot of test (Windows)
git add . -u
git commit -m "Saving files before refreshing line endings"
npm run eol