在 Selenium 中编写 Sleep 来加载页面中的元素？

Question

i wrote some codes for comparing prices from Website with a CSV file, my test works good but it takes long time (1 Minuet). I used Sleep before finding every elements in Webpage. Do you have any other way to write this test that run codes faster, With this method it takes 1 second before loading every price and then comparing with prices in CSV file.On the other hand without sleep my code doesn't work because of loading page and finding elements.

public class TestBikeInsurancePrice extends HepsterTest {    
private void prepareTest() {
        initiateBrowserWebShop();
        var url = baseUrl + "/fahrradversicherung-test-2020";
        driver.get(url);
        handleCookie(driver);
    }

    @Test(priority = 1)
    void checkBeschädigung() throws FileNotFoundException {
        prepareTest();
        List<CsvPrice> stuff = readFromCSV("resources/price/Test Fahrradversicherung Upload.csv");

        stuff.forEach(csvPrice -> {
            System.out.println(csvPrice.getQualityName() + " " + csvPrice.getCoverageSum() + " " + csvPrice.getDurationTimeUnit() + " " + csvPrice.getDurationRiskPremium());
            Select price = new Select(driver.findElement(By.id("coverageSum")));
            price.selectByValue(csvPrice.getCoverageSum().toString());

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            String qualityName;
            if (csvPrice.getQualityName().equals("Diebstahl")) qualityName = "Nur Diebstahl";
            else qualityName = csvPrice.getQualityName();
            driver.findElement(By.xpath("//*[contains(text(),'" + qualityName + "')]")).click();

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            String duration;
            if (!csvPrice.getDurationTimeUnit().equals("MONTHS")) duration = "Preisvorteil";
            else duration = "flexibel, mtl. kündbar";
            driver.findElement(By.xpath("//*[contains(text(),'" + duration + "')]")).click();

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            WebElement priceElement = driver.findElement(By.xpath("//*[@id='product-configurator-spinner']//parent::span"));
            String priceAsString = priceElement.getText().split(" ")[0];
            System.out.println(priceAsString);
            Assert.assertEquals(csvPrice.getPriceBasePrice().setScale(2), new BigDecimal(priceAsString.replace(",", ".")).setScale(2));
        });
    }

Answer 1

Real Problem while using: Thread.sleep()

Thread.sleep() is considered as the worst case of explicit wait because it has to wait for the full time specified as the argument of Thread.sleep(3000), before proceeding further.

As a result, the next step had to wait for the full time to get over.

Solution: Change the Thread.sleep() into explicit wait .

In Selenium, in that situation "Waits" comes handy or play an important role in executing tests.

There are three type wait in Selenium.

1. Implicit wait: In implicit wait, the WebDriver polls the DOM for a certain duration when trying to find any element. This can be useful when certain elements on the webpage are not available immediately and need some time to load.

Code:

WebDriver driver = new FirefoxDriver();
driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

2. Explicit wait Explicit waits allow our code to halt program execution, or freeze the thread, until the condition you pass it resolves. The condition is called with a certain frequency until the timeout of the wait is elapsed. This means that for as long as the condition returns a falsy value, it will keep trying and waiting.

Code:

WebDriverWait wait = new WebDriverWait(driver, 10);
wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("YOUR-LOCATOR")));

3. FluentWait: FluentWait instance defines the maximum amount of time to wait for a condition, as well as the frequency with which to check the condition.

Code:

//Declare and initialise a fluent wait
FluentWait wait = new FluentWait(driver);
//Specify the timout of the wait
wait.withTimeout(5000, TimeUnit.MILLISECONDS);
//Sepcify polling time
wait.pollingEvery(250, TimeUnit.MILLISECONDS);
//Specify what exceptions to ignore
wait.ignoring(NoSuchElementException.class)

//This is how we specify the condition to wait on.
//This is what we will explore more in this chapter
wait.until(ExpectedConditions.alertIsPresent());

Ref:

https://www.selenium.dev/documentation/en/webdriver/waits/

https://www.browserstack.com/guide/wait-commands-in-selenium-webdriver

Answer 2

Explicit wait: Explicit waits are available to Selenium clients for imperative, procedural languages. They allow your code to halt program execution, or freeze the thread, until the condition you pass it resolves. The condition is called with a certain frequency until the timeout of the wait is elapsed. This means that for as long as the condition returns a falsy value, it will keep trying and waiting.

I have added explicit wait to the code.

WebDriverWait wait = new WebDriverWait(driver,10);
        
stuff.forEach(csvPrice -> {
            System.out.println(csvPrice.getQualityName() + " " + csvPrice.getCoverageSum() + " " + csvPrice.getDurationTimeUnit() + " " + csvPrice.getDurationRiskPremium());
            wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("coverageSum")));
            Select price = new Select(driver.findElement(By.id("coverageSum")));
            price.selectByValue(csvPrice.getCoverageSum().toString());


            String qualityName;
            if (csvPrice.getQualityName().equals("Diebstahl")) qualityName = "Nur Diebstahl";
            else qualityName = csvPrice.getQualityName();
            wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//*[contains(text(),'" + qualityName + "')]")));
            driver.findElement(By.xpath("//*[contains(text(),'" + qualityName + "')]")).click();

            String duration;
            if (!csvPrice.getDurationTimeUnit().equals("MONTHS")) duration = "Preisvorteil";
            else duration = "flexibel, mtl. kündbar";
            wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//*[contains(text(),'" + duration + "')]")));
            driver.findElement(By.xpath("//*[contains(text(),'" + duration + "')]")).click();

            wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//*[@id='product-configurator-spinner']//parent::span")));
            WebElement priceElement = driver.findElement(By.xpath("//*[@id='product-configurator-spinner']//parent::span"));
            String priceAsString = priceElement.getText().split(" ")[0];
            System.out.println(priceAsString);
            Assert.assertEquals(csvPrice.getPriceBasePrice().setScale(2), new BigDecimal(priceAsString.replace(",", ".")).setScale(2));
        });