Change up 'clean desktop' check again (use a util function)

Well, that OCR needle isn't working out so great, as it seems
to match when it shouldn't:

https://openqa.fedoraproject.org/tests/119217#step/_graphical_wait_login/5

So let's try another approach. Ditch the OCR needle and have a
function for checking we're at a clean desktop. It does the
normal needle match, but if we're on GNOME, it also tries
hitting alt+f1 and seeing if we're at the overview; if so, it
hits alt+f1 again (to go back to the desktop) and returns.

lib/utils.pm

@@ -7,7 +7,7 @@ use Exporter;
 
 use lockapi;
 use testapi;
-our @EXPORT = qw/run_with_error_check type_safely type_very_safely desktop_vt boot_to_login_screen console_login console_switch_layout desktop_switch_layout console_loadkeys_us do_bootloader get_milestone boot_decrypt check_release menu_launch_type start_cockpit repo_setup gnome_initial_setup anaconda_create_user/;
+our @EXPORT = qw/run_with_error_check type_safely type_very_safely desktop_vt boot_to_login_screen console_login console_switch_layout desktop_switch_layout console_loadkeys_us do_bootloader get_milestone boot_decrypt check_release menu_launch_type start_cockpit repo_setup gnome_initial_setup anaconda_create_user check_desktop_clean/;
 
 sub run_with_error_check {
     my ($func, $error_screen) = @_;
@@ -482,3 +482,41 @@ sub anaconda_create_user {
         assert_and_click "anaconda_spoke_done";
     }
 }
+
+sub check_desktop_clean {
+    # Check we're at a 'clean' desktop. This used to be a simple
+    # needle check, but Rawhide's default desktop is now one which
+    # changes over time, and the GNOME top bar is now translucent
+    # by default; together these changes mean it's impossible to
+    # make a reliable needle, so we need something more tricksy to
+    # cover that case. 'tries' is the amount of check cycles to run
+    # before giving up and failing; each cycle should take ~3 secs.
+    my %args = (
+        tries => 10,
+        @_
+    );
+    foreach my $i (1..$args{tries}) {
+        # we still *do* the needle check, for all cases it covers
+        return if (check_screen "graphical_desktop_clean", 1);
+        # now do the special GNOME case
+        if (get_var("DESKTOP") eq "gnome") {
+            send_key "alt-f1";
+            if (check_screen "overview_app_grid", 2) {
+                send_key "alt-f1";
+                wait_still_screen 3;
+                # go back to the desktop, if we're still at the app
+                # grid (can be a bit fuzzy depending on response lag)
+                while (check_screen "overview_app_grid", 1) {
+                    send_key "alt-f1";
+                    wait_still_screen 3;
+                }
+                return;
+            }
+        }
+        else {
+            # to keep the timing equal
+            sleep 2;
+        }
+    }
+    die "Clean desktop not reached!";
+}

needles/gnome/desktop_clean-20170616-rawhide_ocr.json

@@ -1,25 +0,0 @@
-{
-    "area": [
-        {
-            "height": 15,
-            "type": "ocr",
-            "width": 67,
-            "xpos": 9,
-            "ypos": 6
-        },
-        {
-            "height": 1,
-            "type": "match",
-            "width": 1,
-            "xpos": 946,
-            "ypos": 12
-        }
-    ],
-    "properties": [],
-    "tags": [
-        "DESKTOP-gnome",
-        "ENV-DISTRI-fedora",
-        "LANGUAGE-english",
-        "graphical_desktop_clean"
-    ]
-}

needles/gnome/overview_app_grid.json

@@ -0,0 +1,16 @@
+{
+    "area": [
+        {
+            "height": 45,
+            "type": "match",
+            "width": 45,
+            "xpos": 24,
+            "ypos": 657
+        }
+    ],
+    "properties": [],
+    "tags": [
+        "DESKTOP-gnome",
+        "overview_app_grid"
+    ]
+}

tests/_graphical_input.pm

@@ -26,7 +26,7 @@ sub run {
         send_key "esc";
         send_key "esc";
         send_key "esc";
-        assert_screen "graphical_desktop_clean";
+        check_desktop_clean;
     }
 }
 

tests/_graphical_wait_login.pm

@@ -89,7 +89,7 @@ sub run {
         # Move the mouse somewhere it won't highlight the match areas
         mouse_set(300, 200);
         # KDE can take ages to start up
-        assert_screen "graphical_desktop_clean", 120;
+        check_desktop_clean(tries=>40);
     }
 }
 

tests/desktop_browser.pm

@@ -14,7 +14,7 @@ use utils;
 
 sub run {
     my $self = shift;
-    assert_screen 'graphical_desktop_clean';
+    check_desktop_clean;
     send_key 'alt-f1';
     # wait out animations
     wait_still_screen 2;

tests/desktop_notifications.pm

@@ -65,7 +65,7 @@ sub run {
         type_very_safely get_var("USER_PASSWORD", "weakpassword");
         send_key 'ret';
     }
-    assert_screen 'graphical_desktop_clean', 90;
+    check_desktop_clean(tries=>30);
     # now, WE WAIT. this is just an unconditional wait - rather than
     # breaking if we see an update notification appear - so we catch
     # things that crash a few minutes after startup, etc.

tests/desktop_terminal.pm

@@ -5,7 +5,7 @@ use utils;
 
 sub run {
     my $self=shift;
-    assert_screen 'graphical_desktop_clean';
+    check_desktop_clean;
     menu_launch_type('terminal');
     wait_still_screen 5;
     # need to be root