Rollup merge of #98671 - GuillaumeGomez:source-sidebar-fixes, r=notriddle

Fix source sidebar bugs

This PR fixes the following two bugs:

![Screenshot from 2022-06-29 14-39-58](https://user-images.githubusercontent.com/3050060/176449070-3e3762da-2bfe-4acf-8eb0-34f6eb4c94ed.png)
![Screenshot from 2022-06-29 15-05-09](https://user-images.githubusercontent.com/3050060/176449073-b164820b-bd71-4b1a-990c-bba4e5fce196.png)

I added regression tests to prevent them to happen again.

I think we should backport it to beta as well.

You can test it [here](https://rustdoc.crud.net/imperio/source-sidebar-fixes/src/std/lib.rs.html).

cc ```@jsha```
r? ```@notriddle```

2 files changed, 38 insertions, 2 deletions

diff --git a/src/test/rustdoc-gui/sidebar-source-code-display.goml b/src/test/rustdoc-gui/sidebar-source-code-display.goml
index 8f53e8627ee..c441f84a821 100644
--- a/src/test/rustdoc-gui/sidebar-source-code-display.goml
+++ b/src/test/rustdoc-gui/sidebar-source-code-display.goml
@@ -116,3 +116,39 @@ assert-css: (
     "#source-sidebar .expand + .children .folders .name",
     {"color": "rgb(255, 180, 76)", "background-color": "rgb(20, 25, 31)"},
 )
+
+// Now checking on mobile devices.
+size: (500, 700)
+reload:
+// Waiting for the sidebar to be displayed...
+wait-for-css: ("#sidebar-toggle", {"visibility": "visible", "opacity": 1})
+
+// We now check it takes the full size of the display.
+assert-property: ("body", {"clientWidth": "500", "clientHeight": "700"})
+assert-property: (".sidebar", {"clientWidth": "500", "clientHeight": "700"})
+
+// We now check the display of the toggle once the sidebar is expanded.
+assert-property: ("#sidebar-toggle", {"clientWidth": "500", "clientHeight": "39"})
+assert-css: (
+    "#sidebar-toggle",
+    {
+        "border-top-width": "0px",
+        "border-right-width": "0px",
+        "border-left-width": "0px",
+        "border-bottom-width": "1px",
+    },
+)
+
+// We now check that the scroll position is kept when opening the sidebar.
+click: "#sidebar-toggle"
+wait-for-css: (".sidebar", {"width": "0px"})
+// We scroll to line 117 to change the scroll position.
+scroll-to: '//*[@id="117"]'
+assert-window-property: {"pageYOffset": "2519"}
+// Expanding the sidebar...
+click: "#sidebar-toggle"
+wait-for-css: (".sidebar", {"width": "500px"})
+click: "#sidebar-toggle"
+wait-for-css: (".sidebar", {"width": "0px"})
+// The "scrollTop" property should be the same.
+assert-window-property: {"pageYOffset": "2519"}
diff --git a/src/test/rustdoc-gui/sidebar-source-code.goml b/src/test/rustdoc-gui/sidebar-source-code.goml
index 724520bc399..86df478fa1d 100644
--- a/src/test/rustdoc-gui/sidebar-source-code.goml
+++ b/src/test/rustdoc-gui/sidebar-source-code.goml
@@ -18,8 +18,8 @@ assert: "nav.sidebar"
 
 // We now switch to mobile mode.
 size: (600, 600)
-// We check that the sidebar has the expected width (0 and 1px for the border).
-assert-css: ("nav.sidebar", {"width": "1px"})
+// We check that the sidebar has the expected width (0).
+assert-css: ("nav.sidebar", {"width": "0px"})
 // We expand the sidebar.
 click: "#sidebar-toggle"
 assert-css: (".source-sidebar-expanded nav.sidebar", {"width": "600px"})