Careeroza

Console Logs and JavaScript Errors

Listening With LogInspector (BiDi)

A page can look fine while JavaScript errors are thrown in the background. Capture them and fail the test, or attach them to the report.

import org.openqa.selenium.bidi.module.LogInspector;
import org.openqa.selenium.bidi.log.*;

ChromeOptions options = new ChromeOptions();
options.setCapability("webSocketUrl", true);
WebDriver driver = new ChromeDriver(options);

List<String> jsErrors = new CopyOnWriteArrayList<>();
try (LogInspector logs = new LogInspector(driver)) {
    logs.onConsoleEntry(entry -> System.out.println("console." + entry.getMethod() + ": " + entry.getText()));
    logs.onJavaScriptException(ex -> jsErrors.add(ex.getText()));

    driver.get("https://shopease.example.com/cart");
    driver.findElement(By.id("checkout")).click();
}
Assert.assertTrue(jsErrors.isEmpty(), "JavaScript errors: " + jsErrors);

What You See

Example

mvn test -Dtest=CartConsoleTest

Example output

console.log: cart loaded, 2 items
console.warn: coupon service slow (1840 ms)
[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0
[ERROR] CartConsoleTest.noJsErrorsOnCheckout:38 JavaScript errors: [TypeError: Cannot read properties of undefined (reading 'pincode')] expected [true] but found [false]

Note: This caught a real bug: the checkout script crashed for users without a saved address, even though the button still looked normal.