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Monocart Coverage Reports

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A JavaScript code coverage tool to generate native V8 reports or Istanbul reports.

Usage

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

Options

Available Reports

V8 build-in reports (V8 data only):

  • v8
    • Features:
      • A Brand-New V8 Coverage Report User Interface
      • Support for Native Byte Statistics
      • Support processing big data with high performance
      • Coverage for Any Runtime Code
      • CSS Coverage Support
      • Better Support for Sourcemap Conversion
    • Demos: V8 and more

Istanbul build-in reports (both V8 and Istanbul data):

Other build-in reports (both V8 and Istanbul data):

  • codecov Save coverage data to a json file with Codecov format (defaults to codecov.json), see example.

  • codacy Save coverage data to a json file with Codacy API format (defaults to codacy.json).

  • console-summary shows coverage summary in the console.

  • console-details Show coverage details in the console. Like text, 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 to coverage-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 to coverage-details.md).

  • raw only keep all original data, which can be used for other reports input with inputDir. 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

Multiple Reports:

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);

Compare Reports

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 ❌ ✅ ❌

Collecting Istanbul Coverage Data

Collecting V8 Coverage Data

Collecting V8 Coverage Data with Playwright

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, css

Collecting Raw V8 Coverage Data with Puppeteer

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

Collecting V8 Coverage Data from Node.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 the dir 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

  • 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

  • Inspector API

    • Connecting to the V8 inspector and enable V8 coverage.
    • Taking coverage data and adding it to the report.
    • Example:

    node ./test/test-node-ins.js

    • vm Example (scriptOffset):

    node ./test/test-node-vm.js

  • 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 the v8.takeCoverage() interface can be accomplished through the Runtime.evaluate of the CDP.
    • Example for koa web server:

    node ./test/test-node-koa.js

  • Child Process + NODE_V8_COVERAGE

Collecting V8 Coverage Data with CDPClient API

  • 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();
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();
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();
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
})

V8 Coverage Data API

// 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 ❌

Filtering Results

Using entryFilter and sourceFilter to filter the results for V8 report

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
    }
};

Using filter instead of entryFilter and sourceFilter

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
    }
};

Resolve sourcePath for the Source Files

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;
    }
}

Adding Empty Coverage for Untested Files

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);
        }
    }
};

onEnd Hook

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);
        }
    }
}

Ignoring Uncovered Codes

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');
}
/* c8 ignore start */
function uncovered() {
}
/* c8 ignore stop */

/* node:coverage disable */
function uncovered() {
}
/* node:coverage enable */

Multiprocessing Support

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();

Command Line

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 the dir.

  • 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 or mcr --help

  • Use -- to separate sub CLI args

mcr -c mcr.config.js -- sub-cli -c sub-cli.config.js

Config File

Loading config file by priority:

  • Custom config file:
    • CLI: mcr --config <my-config-file-path>
    • API: await mcr.loadConfig("my-config-file-path")
  • mcr.config.js
  • mcr.config.cjs
  • mcr.config.mjs
  • mcr.config.json - json format
  • mcr.config.ts (requires preloading the ts execution module)

Merge Coverage Reports

The following usage scenarios may require merging coverage reports:

  • When the code is executed in different environments, like Node.js server side and browser client 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 with Jest might cover certain parts of the code, while end-to-end tests with Playwright 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.

Automatic Merging

  • The MCR will automatically merge all the added coverage data when executing generate(). 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 executing generate(), see example nextjs-with-playwright
  • Using Codecov, a popular online code coverage service, which supports automatic merging of reports. Please use report codecov, it will generate report file codecov.json. If multiple codecov.json files are generated, upload all these files, they will be automatically merged. see Codecov and merging reports

Manual Merging

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.

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 from e2e test, which is output to ./coverage-reports/e2e/raw. E2E test examples:

  • Then create a script merge-coverage.js to generate a merged report with option inputDir.

// 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

Common issues

Unexpected 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.

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)

Unparsable source

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;
    }
}

JavaScript heap out of memory

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

Debug for Coverage and Sourcemap

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.

  • Generate additional source and sourcemap files to cache or raw dir
const coverageOptions = {
    logging: 'debug',
    sourceMap: true
};
  • Show time logs with env MCR_LOG_TIME
process.env.MCR_LOG_TIME = true

Integration with Any Testing Framework

  • 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
  • CLI
    • Wrapping with any CLI. mcr your-cli --your-arguments
    • see Command line

Integration Examples

Playwright

c8

  • c8 has integrated MCR as an experimental feature since v10.1.0
c8 --experimental-monocart --reporter=v8 --reporter=console-details node foo.js

CodeceptJS

VSCode

Jest

Vitest

Node Test Runner

Puppeteer

Cypress

WebdriverIO

Storybook Test Runner

TestCafe

Selenium Webdriver

Mocha

mcr mocha ./test/**/*.js

TypeScript

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

AVA

mcr ava

Codecov

codecov

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

Codacy

Codacy

  • 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

Coveralls

Coverage Status

  • 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

Sonar Cloud

Coverage

  • 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/*

Contributing

  • 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

Thanks

About

A code coverage tool to generate native V8 reports or Istanbul reports.

Topics

testing coverage v8 code reports reporter istanbul code-coverage monocart

Resources

Readme

License

MIT license
Activity

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2 watching

Forks

8 forks
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Releases 15

2.11.0 Latest
Oct 3, 2024
+ 14 releases

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