xpath

name

xpath

description

Build XPath selectors with Biloba's b.XPath() mini-DSL — tag/id/class/text/attribute predicates, boolean logic with b.XPredicate(), tree navigation (Child/Descendant/Parent/Ancestor/siblings), WithChildMatching + b.RelativeXPath, indexing (Nth/First/Last), and the XPath().WithText text predicates. Use when constructing or debugging an XPath selector for a Biloba action or matcher — the rare power tool after CSS and semantic locators. Covers the common pitfalls (XPredicate, RelativeXPath, no shadow/iframe crossing).

The Biloba XPath DSL

XPath is the rare power tool, reached for after CSS and semantic locators (see biloba:write-tests): use it for axis/relationship/ordinal queries those can't express (an ancestor, a following-sibling, "the ul that has a child li saying X") or exact text()-node matching. It's native and fast but verbose, and — unlike CSS (>>>) and locators — it does not pierce shadow roots or iframes. Biloba's DSL builds the gnarly query string for you; any Biloba action/matcher takes the resulting XPath as its selector. Docs: https://onsi.github.io/biloba/#the-xpath-dsl.

b.XPath() returns a value of type XPath string — chainable, and printable for inspection: fmt.Println(b.XPath("div").WithClass("c")).

Starting a query

b.XPath()                 // //*        — any element
b.XPath("div")            // //div      — by tag
b.XPath("//div[@id='x']") // verbatim   — anything starting with / or ./

Predicates (refine the current node)

b.XPath().WithID("submit")               // @id = 'submit'
b.XPath().WithClass("red").WithClass("lg") // both classes
b.XPath("button").WithText("Next")          // exact full text
b.XPath("li").WithTextStartsWith("Chapter")
b.XPath("q").WithTextContains("dream")
b.XPath("button").HasAttr("disabled")       // attribute present
b.XPath("input").WithAttr("type", "text")   // attribute equals
b.XPath("input").WithAttrStartsWith("name", "astro")
b.XPath().WithAttrContains("name", "bueller")

Boolean logic — needs b.XPredicate()

The operands of And/Or/Not are predicates, built with b.XPredicate() (not b.XPath()). This is the #1 gotcha:

// a button labelled "Add Comment" that is not disabled
b.XPath("button").WithText("Add Comment").Not(b.XPredicate().HasAttr("disabled"))

// a red Error div or an orange Warning div, but not a fire-drill
b.XPath("div").Or(
	b.XPredicate().And(b.XPredicate().WithClass("red"), b.XPredicate().WithText("Error")),
	b.XPredicate().And(b.XPredicate().WithClass("orange"), b.XPredicate().WithText("Warning")),
).Not(b.XPredicate().HasAttr("fire-drill"))

Navigating the tree

b.XPath("div").WithClass("comments").Child()       // any direct child
b.XPath("div").WithClass("comments").Child("p")    // direct <p> children
b.XPath("div").WithID("top").Descendant("li")      // any-depth <li>
b.XPath("div").WithClass("comments").Parent()
b.XPath("div").WithID("bottom").Ancestor("section").WithClass("outer")
b.XPath("li").WithClass("red").FollowingSibling("li").WithClass("blue")
b.XPath("li").WithClass("red").PrecedingSibling()

Each step can be further refined with the predicate methods above (.Child("p").WithClass("highlight").WithText("User")).

Selecting by a child — needs b.RelativeXPath()

WithChildMatching takes a relative (./) predicate, built with b.RelativeXPath():

// the <ul> that has a child <li> with text "igloo"
b.XPath("ul").WithChildMatching(b.RelativeXPath("li").WithText("igloo"))

Indexing

b.XPath("ul").Nth(2)                          // the 2nd <ul> (1-based)
b.XPath("ul").Nth(2).Descendant("li").Last()  // its last <li>
someList.First()

Prefer a locator for "the element that says X"

Don't reach for XPath's text() predicates as a first move — prefer the locator engine (see biloba:write-tests): b.ByText("Submit") / b.ByTextContains("Welcome") match visible text; b.ByRole("button").WithName("Save") and b.ByLabel("Email") cover role/label. Locators compose — .ContainingText/.Containing/.And/.Or/.Within/.Nth (all accepting any selector) — and pierce open shadow roots automatically, which XPath cannot. Use the XPath DSL's WithText only to scope an exact text() match to a specific tag: b.XPath("button").WithText("Submit").

Reuse partial queries

Because the DSL returns an XPath string, build a base once and extend it:

users := b.XPath("div").WithID("user-list").Descendant()
Eventually(users.WithText("Sally")).Should(b.HaveClass("online"))
Eventually(users.WithText("Jane")).Should(b.HaveClass("online"))

Limits

XPath selectors do not cross shadow DOM or iframe boundaries — the >>> piercing combinator is CSS-only (see biloba:write-tests). For those, use a CSS selector with >>>, or reach for a semantic locator (b.ByRole/b.ByText/b.ByLabel), which pierces open shadow roots automatically.