feat(coverage): add an option to collect coverage of anonymous scripts (#2796)

This patch adds `reportAnonymousScripts` option to the `coverage.startJSCoverage` method. With this option, anonymous scripts are reported as well.

Fixes #2777

docs/api.md

@@ -2939,8 +2939,11 @@ _To output coverage in a form consumable by [Istanbul](https://github.com/istanb
 #### coverage.startJSCoverage(options)
 - `options` <[Object]>  Set of configurable options for coverage
   - `resetOnNavigation` <[boolean]> Whether to reset coverage on every navigation. Defaults to `true`.
+  - `reportAnonymousScripts` <[boolean]> Whether anonymous scripts generated by the page should be reported. Defaults to `false`.
 - returns: <[Promise]> Promise that resolves when coverage is started
 
+> **NOTE** Anonymous scripts are ones that don't have an associated url. These are scripts that are dynamically created on the page using `eval` or `new Function`. If `reportAnonymousScripts` is set to `true`, anonymous scripts will have `__puppeteer_evaluation_script__` as their URL.
+
 #### coverage.stopCSSCoverage()
 - returns: <[Promise]<[Array]<[Object]>>> Promise that resolves to the array of coverage reports for all stylesheets
   - `url` <[string]> StyleSheet URL
@@ -2952,14 +2955,14 @@ _To output coverage in a form consumable by [Istanbul](https://github.com/istanb
 > **NOTE** CSS Coverage doesn't include dynamically injected style tags without sourceURLs.
 
 #### coverage.stopJSCoverage()
-- returns: <[Promise]<[Array]<[Object]>>> Promise that resolves to the array of coverage reports for all non-anonymous scripts
+- returns: <[Promise]<[Array]<[Object]>>> Promise that resolves to the array of coverage reports for all scripts
   - `url` <[string]> Script URL
   - `text` <[string]> Script content
   - `ranges` <[Array]<[Object]>> Script ranges that were executed. Ranges are sorted and non-overlapping.
     - `start` <[number]> A start offset in text, inclusive
     - `end` <[number]> An end offset in text, exclusive
 
-> **NOTE** JavaScript Coverage doesn't include anonymous scripts. However, scripts with sourceURLs are
+> **NOTE** JavaScript Coverage doesn't include anonymous scripts by default. However, scripts with sourceURLs are
 reported.
 
 [Array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array "Array"

lib/Coverage.js

@@ -16,6 +16,8 @@
 
 const {helper, debugError, assert} = require('./helper');
 
+const {EVALUATION_SCRIPT_URL} = require('./ExecutionContext');
+
 /**
  * @typedef {Object} CoverageEntry
  * @property {string} url
@@ -83,6 +85,7 @@ class JSCoverage {
   async start(options = {}) {
     assert(!this._enabled, 'JSCoverage is already enabled');
     this._resetOnNavigation = options.resetOnNavigation === undefined ? true : !!options.resetOnNavigation;
+    this._reportAnonymousScripts = !!options.reportAnonymousScripts;
     this._enabled = true;
     this._scriptURLs.clear();
     this._scriptSources.clear();
@@ -109,8 +112,11 @@ class JSCoverage {
    * @param {!Protocol.Debugger.scriptParsedPayload} event
    */
   async _onScriptParsed(event) {
-    // Ignore anonymous scripts
-    if (!event.url)
+    // Ignore puppeteer-injected scripts
+    if (event.url === EVALUATION_SCRIPT_URL)
+      return;
+    // Ignore other anonymous scripts unless the reportAnonymousScripts option is true.
+    if (!event.url && !this._reportAnonymousScripts)
       return;
     try {
       const response = await this._client.send('Debugger.getScriptSource', {scriptId: event.scriptId});

lib/ExecutionContext.js

@@ -16,6 +16,9 @@
 
 const {helper, assert} = require('./helper');
 
+const EVALUATION_SCRIPT_URL = '__puppeteer_evaluation_script__';
+const SOURCE_URL_REGEX = /^[\040\t]*\/\/[@#] sourceURL=\s*(\S*?)\s*$/m;
+
 class ExecutionContext {
   /**
    * @param {!Puppeteer.CDPSession} client
@@ -61,11 +64,14 @@ class ExecutionContext {
    * @return {!Promise<!JSHandle>}
    */
   async evaluateHandle(pageFunction, ...args) {
+    const suffix = `//# sourceURL=${EVALUATION_SCRIPT_URL}`;
+
     if (helper.isString(pageFunction)) {
       const contextId = this._contextId;
       const expression = /** @type {string} */ (pageFunction);
+      const expressionWithSourceUrl = SOURCE_URL_REGEX.test(expression) ? expression : expression + '\n' + suffix;
       const {exceptionDetails, result: remoteObject} = await this._client.send('Runtime.evaluate', {
-        expression,
+        expression: expressionWithSourceUrl,
         contextId,
         returnByValue: false,
         awaitPromise: true,
@@ -76,8 +82,11 @@ class ExecutionContext {
       return this._objectHandleFactory(remoteObject);
     }
 
+    if (typeof pageFunction !== 'function')
+      throw new Error('The following is not a function: ' + pageFunction);
+
     const { exceptionDetails, result: remoteObject } = await this._client.send('Runtime.callFunctionOn', {
-      functionDeclaration: pageFunction.toString(),
+      functionDeclaration: pageFunction.toString() + '\n' + suffix + '\n',
       executionContextId: this._contextId,
       arguments: args.map(convertArgument.bind(this)),
       returnByValue: false,
@@ -239,4 +248,4 @@ class JSHandle {
 }
 
 helper.tracePublicAPI(JSHandle);
-module.exports = {ExecutionContext, JSHandle};
+module.exports = {ExecutionContext, JSHandle, EVALUATION_SCRIPT_URL};

test/assets/jscoverage/eval.html

@@ -0,0 +1 @@
+<script>eval('console.log("foo")')</script>

test/coverage.spec.js

@@ -38,12 +38,27 @@ module.exports.addTests = function({testRunner, expect}) {
       expect(coverage.length).toBe(1);
       expect(coverage[0].url).toBe('nicename.js');
     });
-    it('should ignore anonymous scripts', async function({page, server}) {
-      await page.coverage.startJSCoverage();
-      await page.goto(server.EMPTY_PAGE);
-      await page.evaluate(() => console.log(1));
-      const coverage = await page.coverage.stopJSCoverage();
-      expect(coverage.length).toBe(0);
+    describe('anonymous scripts coverage', function() {
+      it('should ignore eval() scripts by default', async function({page, server}) {
+        await page.coverage.startJSCoverage();
+        await page.goto(server.PREFIX + '/jscoverage/eval.html');
+        const coverage = await page.coverage.stopJSCoverage();
+        expect(coverage.length).toBe(1);
+      });
+      it('shouldn\'t ignore eval() scripts if reportAnonymousScripts is true', async function({page, server}) {
+        await page.coverage.startJSCoverage({reportAnonymousScripts: true});
+        await page.goto(server.PREFIX + '/jscoverage/eval.html');
+        const coverage = await page.coverage.stopJSCoverage();
+        expect(coverage.length).toBe(2);
+      });
+      it('should ignore injected scripts regardless of reportAnonymousScripts', async function({page, server}) {
+        await page.coverage.startJSCoverage({reportAnonymousScripts: true});
+        await page.goto(server.EMPTY_PAGE);
+        await page.evaluate('console.log("foo")');
+        await page.evaluate(() => console.log('bar'));
+        const coverage = await page.coverage.stopJSCoverage();
+        expect(coverage.length).toBe(0);
+      });
     });
     it('should report multiple scripts', async function({page, server}) {
       await page.coverage.startJSCoverage();