I try to write xpath expressions so that my tests won't be broken by small design changes. So instead of the expressions that Selenium IDE generates, I write my own.
Here's an issue:
//input[#name='question'][7]
This expression doesn't work at all. Input nodes named 'question' are spread across the page. They're not siblings.
I've tried using intermediate expression, but it also fails.
(//input[#name='question'])[2]
error = Error: Element (//input[#name='question'])[2] not found
That's why I suppose Seleniun has a wrong implementation of XPath.
According to XPath docs, the position predicate must filter by the position in the nodeset, so it must find the seventh input with the name 'question'. In Selenium this doesn't work. CSS selectors (:nth-of-kind) neither.
I had to write an expression that filters their common parents:
//*[contains(#class, 'question_section')][7]//input[#name='question']
Is this a Selenium specific issue, or I'm reading the specs wrong way? What can I do to make a shorter expression?
Here's an issue:
//input[#name='question'][7]
This expression doesn't work at all.
This is a FAQ.
[] has a higher priority than //.
The above expression selects every input element with #name = 'question', which is the 7th child of its parent -- and aparently the parents of input elements in the document that is not shown don't have so many input children.
Use (note the brackets):
(//input[#name='question'])[7]
This selects the 7th element input in the document that satisfies the conditions in the predicate.
Edit:
People, who know Selenium (Dave Hunt) suggest that the above expression is written in Selenium as:
xpath=(//input[#name='question'])[7]
If you want the 7th input with name attribute with a value of question in the source then try the following:
/descendant::input[#name='question'][7]
Related
I learned that every Xpath expression is also a valid Xquery expression. I'm using Oxygen 16.1 with this sample XML:
<actors>
<actor filmcount="4" sex="m" id="15">Anderson, Jeff</actor>
<actor filmcount="9" sex="m" id="38">Bishop, Kevin</actor>
</actors>
My expression is:
//actor/#id
When I evaluate this expression in Oxygen with Xpath 3.0, I get exactly what I expect:
15
38
However, when I evaluate this expression with Xquery 3.0 (also 1.0), I get the message: "Your query returned an empty sequence.
Can anyone provide any insight as to why this is, and how I can write the equivalent Xquery statement to get what the Xpath statement did above?
Other XQuery implementations do support this query
If you want to validate that your query (as corrected per discussion in comments) does in fact work with other XQuery implementations when entered exactly as given in the question, you can run it as follows (tested in BaseX):
declare context item := document { <actors>
<actor filmcount="4" sex="m" id="15">Anderson, Jeff</actor>
<actor filmcount="9" sex="m" id="38">Bishop, Kevin</actor>
</actors> };
//actor/#id
Oxygen XQuery needs some extra help
Oxygen XML doesn't support serializing attributes, and consequently discards them from a result sequence when that sequence would otherwise be provided to the user.
Thus, you can work around this with a query such as the following:
//actor/#id/string(.)
data(//actor/#id)
Below applies to a historical version of the question.
Frankly, I would not expect //actors/#id to return anything against that data with any valid XPath or XQuery engine, ever.
The reason is that there's only one place you're recursing -- one // -- and that's looking for actors. The single / between the actors and the #id means that they need to be directly connected, but that's not the case in the data you give here -- there's an actor element between them.
Thus, you need to fix your query. There are numerous queries you could write that would find the data you wanted in this document -- knowing which one is appropriate would require more information than you've provided:
//actor/#id - Find actor elements anywhere, and take their id attribute values.
//actors/actor/#id - Find actors elements anywhere; look for actor elements directly under them, and take the id attribute of such actor elements.
//actors//#id - Find all id attributes in subtrees of actors elements.
//#id - Find id attributes anywhere in the document.
...etc.
I have a certain XPATH-query which I use to get the height from a certain HTML-element which returns me perfectly the desired value when I execute it in Chrome via the XPath Helper-plugin.
//*/div[#class="BarChart"]/*[name()="svg"]/*[name()="svg"]/*[name()="g"]/*[name()="rect" and #class="bar bar1"]/#height
However, when I use the same query via the Get Element Attribute-keyword in the Robot Framework
Get Element Attribute//*/div[#class="BarChart"]/*[name()="svg"]/*[name()="svg"]/*[name()="g"]/*[name()="rect" and #class="bar bar1"]/#height
... then I got an InvalidSelectorException about this XPATH.
InvalidSelectorException: Message: u'invalid selector: Unable to locate an
element with the xpath expression `//*/div[#class="BarChart"]/*[name()="svg"]/*
[name()="svg"]/*[name()="g"]/*[name()="rect" and #class="bar bar1"]/`
So, the Robot Framework or Selenium removed the #-sign and everything after it. I thought it was an escape -problem and added and removed some slashes before the #height, but unsuccessful. I also tried to encapsulate the result of this query in the string()-command but this was also unsuccessful.
Does somebody has an idea to prevent my XPATH-query from getting broken?
It looks like you can't include the attribute axis in the XPath itself when you're using Robot. You need to retrieve the element by XPath, and then specify the attribute name outside that. It seems like the syntax is something like this:
Get Element Attribute xpath=(//*/div[#class="BarChart"]/*[name()="svg"]/*[name()="svg"]/*[name()="g"]/*[name()="rect" and #class="bar bar1"])#height
or perhaps (I've never used Robot):
Get Element Attribute xpath=(//*/div[#class="BarChart"]/*[name()="svg"]/*[name()="svg"]/*[name()="g"]/*[name()="rect" and #class="bar bar1"])[1]#height
This documentation says
attribute_locator consists of element locator followed by an # sign and attribute name, for example "element_id#class".
so I think what I've posted above is on the right track.
You are correct in your observation that the keyword seems to removes everything after the final #. More correctly, it uses the # to separate the element locator from the attribute name, and does this by splitting the string at that final # character.
No amount of escaping will solve the problem as the code isn't doing any parsing at this point. This is the exact code (as of this writing...) that performs that operation:
def _parse_attribute_locator(self, attribute_locator):
parts = attribute_locator.rpartition('#')
...
The simple solution is to drop that trailing slash, so your xpath will look like this:
//*/div[#class="BarChart"]/... and #class="bar bar1"]#height`
I am trying to quickly find a specific node using XPath but it seems my multiple predicates are not working. The div I need has a specific class, but there are 3 others that have it. I want to select the fourth one so I did the following:
//div[#class='myCLass' and 4]
However the "4" is being ignored. Any help? I am new to XPath.
Thanks.
If a xpath query returns a node set you can always use the [OFFSET] operator to access a certain element of it.
Use the following query to access the fourth element that matches the #class='myClass' predicate:
//div[#class='myCLass'][4]
#WilliamNarmontas answer might be an alternative to the syntax showed above.
Alternatively,
//div[#class='myCLass' and position()=4]
The accepted answer works correctly only if all of the div elements have the same parent. Otherwise use:
(//div[#class='myCLass'])[4]
I am trying to find XPath of an element which has no attribute. It can only be identified by its parent's attribute. However, the parent also does not have unique attribute.
Eg: //*[#id="btn"][1]/ul/li[2]/a/span
Here there are 2 elements with id=btn. How do i get the 2nd element. The above syntax gives me 1st element.. However if i use:
//*[#id="btn"][2]/ul/li[2]/a/span
I get an error message
"The xpath expression '//*[#id="btn"][2]/ul/li[2]/a/span' cannot be evaluated or does not result in a WebElement "
Try this, you select those two first, then use brackets around and index them.
(//*[#id="btn"]/ul/li[2]/a/span)[2]
By the way, it's not a good practice to have multiple elements sharing same ids, if you are the developer, may consider change them.
When there is more than a single element with the same locator in a page, how should the next elements be referenced?
Using Xpath locators it's possible to add array notation, e.g. xpath=(//span/div)[1]
But with simple locators?
For example, if there are 3 links identified by "link=Click Here", simply appending [3] won't get the 3rd element.
And where is the authoritative reference for addressing array of elements? I couldn't find any.
Selenium doesn't handle arrays of locators by itself. It just returns the first element that meets your query, so if you want to do that, you have to use xpath, dom or even better, css.
So for the link example you should use:
selenium.click("css=a:contains('Click Here'):nth-child(3)")
Santi is correct that Selenium returns the first element matching your specified locator and you have to apply the appropriate expression of the locator type you use. I thought it would be useful to give the details here, though, for in this case they do border on being "gory details":
CSS
The :nth-child pseudo-class is tricky to use; it has subtleties that are little-known and not clearly documented, even on the W3C pages. Consider a list such as this:
<ul>
<li class="bird">petrel</li>
<li class="mammal">platypus</li>
<li class="bird">albatross</li>
<li class="bird">shearwater</li>
</ul>
Then the selector css=li.bird:nth-child(3) returns the albatross element not the shearwater! The reason for this is that it uses your index (3) into the list of elements that are siblings of the first matching element--unfiltered by the .bird class! Once it has the correct element, in this example the third one, it then applies the bird class filter: if the element in hand matches, it returns it. If it does not, it fails to match.
Now consider the selector css=li.bird:nth-child(2). This starts with the second element--platypus--sees it is not a bird and comes up empty. This manifests as your code throwing a "not found" exception!
What might fit the typical mental model of finding an indexed entry is the CSS :nth-of-type pseudo-class which applies the filter before indexing. Unfortunately, this is not supported by Selenium, according to the official documentation on locators.
XPath
Your question already showed that you know how to do this in XPath. Add an array reference at any point in the expression with square brackets. You could, for example use something like this: //*[#id='abc']/div[3]/p[2]/span to find a span in the second paragraph under the 3rd div under the specified id.
DOM
DOM uses the same square bracket notation as XPath except that DOM indexes from zero while XPath indexes from 1: document.getElementsByTagName("div")[1] returns the second div, not the first div! DOM offers an alternate syntax as well: document.getElementsByTagName("div").item(0) is exactly equivalent. And note that with getElementsByTagName you always have to use an index since it returns a node set, not a single node.