Driver.java

package pl.espeo.sgn.e2e;

import java.util.List;
import org.apache.commons.lang3.StringUtils;
import org.openqa.selenium.By;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebDriverException;
import org.openqa.selenium.WebElement;

/**
 * The WebDriver adapter.
 * @author Witold Szczerba
 */
public class Driver {
    
    private final String sgnAppRootUrl;
    private final WebDriver webDriver;
    private final JavascriptExecutor jsExec;
    
    public Driver(String sgnAppRootUrl, WebDriver webDriver, JavascriptExecutor jsExec) {
        this.sgnAppRootUrl = sgnAppRootUrl;
        this.webDriver = webDriver;
        this.jsExec = jsExec;
    }

    public WebElement find(String description, final By selector) {
        jsExec.executeAsyncScript("var callback = arguments[0]; e2eNotifyWhenReady(callback);");
        List<WebElement> elements = webDriver.findElements(selector);
        if (elements.isEmpty()) {
            throw new RuntimeException("Cannot find: "+describe(description, selector));
        }
        return elements.get(0);
    }

    public String valueByNgModel(String tag, String ngModel) {
        return findByNgModel(tag, ngModel).getAttribute("value");
    }

    public WebElement findByNgModel(String tag, String ngModel) throws RuntimeException {
        String selector = tag + "[ng-model='" + ngModel + "']";
        WebElement webElement;
        try {
            webElement = find("", By.cssSelector(selector));
        } catch (WebDriverException ex) {
            throw new RuntimeException("Invalid CSS selector: " + selector);
        }
        return webElement;
    }

    public void goTo(String path) {
        jsExec.executeAsyncScript("var callback = arguments[0]; e2eNotifyWhenReady(callback);");
        String prefix = path.startsWith("/") ? "#" : "#/";
        webDriver.navigate().to(sgnAppRootUrl + prefix + path);
    }

    private String describe(String description, By selector) {
        return StringUtils.isEmpty(description) ? selector.toString() : (description + " (" + selector + ")");
    }

}

webdriver-e2e.js

angular.module('webdriver-e2e', [])
.run(function($browser) {
  window.e2eNotifyWhenReady = function(callbackWhenReadyFn) {
    $browser.notifyWhenNoOutstandingRequests(callbackWhenReadyFn);
  }
});

Waiting for e2eNotifyWhenReady in Driver#goTo was crucial to stop random test fails.