Encountering a Null Pointer Exception when trying to locate an element on an AngularJS website using Selenium

Question

Encountering a Null Pointer Exception when trying to locate an element on an AngularJS website using Selenium

Testing an AngularJS website with Selenium can be challenging due to angular directives, as mentioned in a blog. Despite encountering some stability issues such as failures and exceptions like "unable to locate Element," "No such element," or "Null pointer exceptions," I have managed to run test cases successfully using Selenium. However, I feel like there might be something missing on my end that is hindering the smooth execution of the tests. Although ProtectorJS is an option, I prefer sticking to Selenium for testing purposes.

Any insights or tips would be greatly appreciated. Thank you in advance.

javascript angularjs selenium protractor

Answer 1

Answer №1

Encountered a similar issue where implicit Selenium waits weren't effective with Angular, and I wanted to avoid complicating my tests with explicit waits that prolonged test execution.

Fortunately, I came across this solution: https://github.com/paul-hammant/ngWebDriver

This is a WebDriver based on Protractor that can be utilized in Selenium testing.

I devised an actions class in which I ensured Angular was ready before executing any actions (clicking, filling forms, checking, etc.). For the code snippet, refer to my response to this query.

Answer 2

Encountered a similar issue where implicit Selenium waits weren't effective with Angular, and I wanted to avoid complicating my tests with explicit waits that prolonged test execution.

Fortunately, I came across this solution: https://github.com/paul-hammant/ngWebDriver

This is a WebDriver based on Protractor that can be utilized in Selenium testing.

I devised an actions class in which I ensured Angular was ready before executing any actions (clicking, filling forms, checking, etc.). For the code snippet, refer to my response to this query.

Answer 3

Answer №2

The issue at hand arises from the fact that the fields you are attempting to access have not yet loaded.

Regrettably, there is no automatic solution available. However, one workaround is to incorporate a snippet of code to pause execution until these elements become accessible:

WebDriverWait.until(findElement(By.xpath("//[@id='id']"));

Alternatively, you could implement a custom wait(ms) function in your script and invoke it accordingly.

Both approaches require considerable additional coding effort to address this particular challenge.

Answer 4

The issue at hand arises from the fact that the fields you are attempting to access have not yet loaded.

Regrettably, there is no automatic solution available. However, one workaround is to incorporate a snippet of code to pause execution until these elements become accessible:

WebDriverWait.until(findElement(By.xpath("//[@id='id']"));

Alternatively, you could implement a custom wait(ms) function in your script and invoke it accordingly.

Both approaches require considerable additional coding effort to address this particular challenge.

Answer 5

Answer №3

To ensure that Angular processed elements are ready, you can wait until all Angular requests have been completed.

Selenium offers a feature known as Explicit Waits to handle such tasks using the ExpectedCondition.

Here is an example of an Expected Condition:

 public static ExpectedCondition<Boolean> checkAngularProcessingStatus() {
return new ExpectedCondition<Boolean>() {
    @Override
    public Boolean apply(WebDriver driver) {
        return Boolean.valueOf(((JavascriptExecutor) driver).executeScript("return (window.angular !== undefined) && (angular.element(document).injector() !== undefined) && (angular.element(document).injector().get('$http').pendingRequests.length === 0)").toString());
    }
};

}

Once this condition is met, we can proceed with our code and wait for all AJAX requests to finish by using the ExpectedCondition within Explicit Waits, which is implemented through WebDriverWait.

WebDriverWait wait = new WebDriverWait(driver, 15, 100);
wait.until(AdditionalConditions.checkAngularProcessingStatus()));

In this process, we utilized the JavascriptExecutor to execute javascript in order to monitor pending requests. If there are no pending requests, we can interact with the element accordingly.

Answer 6

To ensure that Angular processed elements are ready, you can wait until all Angular requests have been completed.

Selenium offers a feature known as Explicit Waits to handle such tasks using the ExpectedCondition.

Here is an example of an Expected Condition:

 public static ExpectedCondition<Boolean> checkAngularProcessingStatus() {
return new ExpectedCondition<Boolean>() {
    @Override
    public Boolean apply(WebDriver driver) {
        return Boolean.valueOf(((JavascriptExecutor) driver).executeScript("return (window.angular !== undefined) && (angular.element(document).injector() !== undefined) && (angular.element(document).injector().get('$http').pendingRequests.length === 0)").toString());
    }
};

}

Once this condition is met, we can proceed with our code and wait for all AJAX requests to finish by using the ExpectedCondition within Explicit Waits, which is implemented through WebDriverWait.

WebDriverWait wait = new WebDriverWait(driver, 15, 100);
wait.until(AdditionalConditions.checkAngularProcessingStatus()));

In this process, we utilized the JavascriptExecutor to execute javascript in order to monitor pending requests. If there are no pending requests, we can interact with the element accordingly.

Encountering a Null Pointer Exception when trying to locate an element on an AngularJS website using Selenium

Answer №1

Answer №2

Answer №3

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