Add line number click GUI test

Author: GuillaumeGomez

src/test/rustdoc-gui/source-code-page.goml

@@ -3,7 +3,7 @@ goto: file://|DOC_PATH|/src/test_docs/lib.rs.html
 // Check that we can click on the line number.
 click: ".line-numbers > span:nth-child(4)" // This is the span for line 4.
 // Ensure that the page URL was updated.
-assert-document-property: ({"URL": "#4"}, ENDS_WITH)
+assert-document-property: ({"URL": "lib.rs.html#4"}, ENDS_WITH)
 assert-attribute: ("//*[@id='4']", {"class": "line-highlighted"})
 // We now check that the good spans are highlighted
 goto: file://|DOC_PATH|/src/test_docs/lib.rs.html#4-6
@@ -17,3 +17,13 @@ compare-elements-position: ("//*[@id='1']", ".rust > code > span", ("y"))
 
 // Assert that the line numbers text is aligned to the right.
 assert-css: (".line-numbers", {"text-align": "right"})
+
+// Now let's check that clicking on something else than the line number doesn't
+// do anything (and certainly not add a `#NaN` to the URL!).
+show-text: true
+goto: file://|DOC_PATH|/src/test_docs/lib.rs.html
+// We use this assert-position to know where we will click.
+assert-position: ("//*[@id='1']", {"x": 104, "y": 103})
+// We click on the left of the "1" span but still in the "line-number" `<pre>`.
+click: (103, 103)
+assert-document-property: ({"URL": "/lib.rs.html"}, ENDS_WITH)