Network Mocking and Request Interception

SHAFT Engine exposes Selenium's Chrome DevTools Protocol (CDP) integration via driver.browser().mock() and driver.browser().intercept(). This allows you to replace API responses with controlled test data and block or modify outgoing requests — all without changing your application code.

info

Network mocking relies on the Chrome DevTools Protocol. Use a Chromium-based browser (Chrome or Edge) when running tests that require this feature.

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Use Cases

Scenario	Recommended approach
Test error states (500, 404)	mock() with a custom status code
Test empty states (no data)	mock() with empty JSON body
Block analytics / tracking calls	intercept() with 204 response
Simulate offline mode	intercept() all requests with network error
Inject controlled test data	mock() with fixed JSON payload

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mock() — Replace Responses

Use mock() to intercept requests matching a condition and return a custom HTTP response instead of the real one.

NetworkMocking.java

import com.shaft.driver.SHAFT;
import org.openqa.selenium.remote.http.Contents;
import org.openqa.selenium.remote.http.HttpResponse;

SHAFT.GUI.WebDriver driver = new SHAFT.GUI.WebDriver();

// Mock an API response
driver.browser().mock(
    request -> request.getUri().contains("/api/users"),
    new HttpResponse()
        .setStatus(200)
        .addHeader("Content-Type", "application/json")
        .setContent(Contents.utf8String("{\"users\": [{\"name\": \"Mock User\"}]}"))
);

// Navigate to the page that calls the mocked API
driver.browser().navigateToURL("https://example.com/dashboard");

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intercept() — Block or Modify Requests

Use intercept() to block or silently replace outbound requests — for example, to suppress analytics calls or simulate unavailable services.

NetworkMocking.java

// Intercept and silence analytics calls
driver.browser().intercept(
    request -> request.getUri().contains("/api/analytics"),
    new HttpResponse().setStatus(204)
);

// Intercept and simulate a server error
driver.browser().intercept(
    request -> request.getUri().contains("/api/checkout"),
    new HttpResponse()
        .setStatus(500)
        .addHeader("Content-Type", "application/json")
        .setContent(Contents.utf8String("{\"error\": \"Internal Server Error\"}"))
);

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Complete Example

NetworkMockingTest.java

import com.shaft.driver.SHAFT;
import org.openqa.selenium.By;
import org.openqa.selenium.remote.http.Contents;
import org.openqa.selenium.remote.http.HttpResponse;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

public class NetworkMockingTest {
    private SHAFT.GUI.WebDriver driver;

    @BeforeMethod
    public void setup() {
        driver = new SHAFT.GUI.WebDriver();
    }

    @Test
    public void testEmptyUserList() {
        driver.browser().mock(
            request -> request.getUri().contains("/api/users"),
            new HttpResponse()
                .setStatus(200)
                .addHeader("Content-Type", "application/json")
                .setContent(Contents.utf8String("{\"users\": []}"))
        );
        driver.browser().navigateToURL("https://example.com/users");
        driver.assertThat(By.id("emptyState")).text().contains("No users found").perform();
    }

    @Test
    public void testServerErrorHandling() {
        driver.browser().mock(
            request -> request.getUri().contains("/api/users"),
            new HttpResponse().setStatus(500)
        );
        driver.browser().navigateToURL("https://example.com/users");
        driver.assertThat(By.id("errorBanner")).text().contains("Something went wrong").perform();
    }

    @AfterMethod
    public void teardown() {
        driver.quit();
    }
}

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tip

Register mocks before navigating to the page. The browser must have the intercept rules in place before any requests are made.

note

Mocks and intercepts registered via mock() and intercept() are scoped to the current browser session and are cleared when the driver is quit.