The beginning of the CSS Selector is wrong.

Searching for .freesim-text-last button span you will find two elements.

Pick the one which you're trying to reach using the follow:

.freesim-text-last button span:nth-of-type(1)

for the first element and

.freesim-text-last button span:nth-of-type(2)

for the second element.

i would inject piece of js to be confident in resolving this issue:

first of all locate element using DOM (verify in firebug):

public void jsClick(){

        JavascriptExecutor js = (JavascriptExecutor) driver;
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append("document.getElementsByTagName('button')[0].click();");
        js.executeScript(stringBuilder.toString());
    }
jsClick();

from the retrospective of your element it be like:

....
stringBuilder.append("document.getElementsByTagName('input')[0].click();");
....

Please, note: document.getElementsByTagName('input') returns you an array of DOM elements. And indexing it properly e.g. document.getElementsByTagName('input')[0], document.getElementsByTagName('input')1, document.getElementsByTagName('input')[2].... ,etc you will be able to locate your element.

Hope this helps you. Regards.

It might not work finding the element because it's not visible in UI - it is loaded but not visible, the easiest way is to move to that element and click on it.

next_button = driver.find_element_by_css_selector('[aria-label=\'Next\']')
actions = ActionChains(driver)
actions.move_to_element(next_button).perform()
next_button.click()

The main problem is at this line:

driver.findElement(By.cssSelector("a:contains('About Google')"));

css doesn't maintain contains() for Selenium WD - See here.

For using contains() you have to use Xpath.

With Xpath your locator will be:

//a[contains(text(), 'About Google')]

and for driver it will be as:

driver.findElement(By.xpath("//a[contains(text(), 'About Google')]"));

For finding links with Selenium you can use:

driver.findElement(By.linkText("your link name here"));

It is limitation of CSS selectors compare to Xpath:

• you can't take parent element with CSS selectors (Xpath has XPath axes)
• you can't use contains (it is only XPath privilege).

BTW
For processing Xpath locators from page you able to use extension for Firefox browser:

• FirePath

• Xpath Checker

You probably don't need LINQ for this. You can use the :not() pseudo-class, one for each value you want to exclude (note the *= in each negation; I'm assuming substring matches here):

driver.FindElements(By.CssSelector("a[href]:not([href*='logoff']):not([href*='client'])"))

An exception is if you have a dynamic list of values that you want to exclude: you can either build your selector programmatically using string.Join() or a loop and then pass it to By.CssSelector(), or you can follow Richard Schneider's answer using LINQ to keep things clean.

When using multiple class names for the same tag within a CSS Selector, they must be separated by a dot instead of a space. Here's the correct way to express your third one:

(By.CSS_SELECTOR, ".ui.dropdown.selection")

OR

(By.CSS_SELECTOR, "div.ui.dropdown.selection").

As for the fourth one, you can't use By.CLASS_NAME with multiple class name components. You would have to pick one, but since that probably won't give you a unique selector, you'll be better off using one of the other ways to form a selector.

Exception in thread "main" org.openqa.selenium.InvalidElementStateException: invalid element state: Failed to execute 'querySelector' on 'Document': 'input[id='login-username']]' is not a valid selector

The error is absolutely correct, because your cssSelector is incorrect. Just omit the last ] square bracket which is extra and try as below:

driver.findElement(By.cssSelector("input[id='login-username']")).sendKeys("asdfasd");

You can also use the #id CSS selector to locate an element with their id attribute value using cssSelector as below:

driver.findElement(By.cssSelector("input#login-username")).sendKeys("asdfasd");

To learn more about the CSS selector, follow this reference.

Selenium also locate an element using the id attribute value of an element directly, so you can locate this element using By.id() as well as below:

driver.findElement(By.id("login-username")).sendKeys("asdfasd");