rustdoc: add test cases for mile wide bar

tests/rustdoc-gui/huge-logo.goml

@@ -7,6 +7,7 @@ set-window-size: (1280, 1024)
 assert-property: (".sidebar-crate .logo-container", {"offsetWidth": "96", "offsetHeight": 48})
 // offsetWidth = width of sidebar, offsetHeight = height + top padding
 assert-property: (".sidebar-crate .logo-container img", {"offsetWidth": "48", "offsetHeight": 64})
+assert-css: (".sidebar-crate .logo-container img", {"border-top-width": "16px", "margin-top": "-16px"})
 
 set-window-size: (400, 600)
 // offset = size + margin

tests/rustdoc-gui/sidebar.goml

@@ -179,3 +179,18 @@ assert-property: (".sidebar .sidebar-crate h2 a", {
     "offsetTop": |index_sidebar_y|,
     "offsetLeft": |index_sidebar_x|,
 })
+
+// Check that the sidebar links touch the left side of the box
+go-to: "file://" + |DOC_PATH| + "/test_docs/index.html"
+assert-position: (".sidebar .block a", {"x": -4})
+assert-position: (".sidebar-crate > h2 > a", {"x": -3})
+
+// Check that the main sidebar links touch the left side of the box
+// but the crate name doesn't, because the logo takes that space
+go-to: "file://" + |DOC_PATH| + "/huge_logo/index.html"
+assert-position: (".sidebar .block a", {"x": -4})
+// when side-by-side, it's not line wrapped
+assert-position-false: (".sidebar-crate > h2 > a", {"x": -3})
+// when line-wrapped, see that it becomes flush-left again
+drag-and-drop: ((205, 100), (108, 100))
+assert-position: (".sidebar-crate > h2 > a", {"x": -3})