Use JavaScript to detect if Selection.modify is available.

dart/tests/try/firefox.applescript

 -- Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 -- for details. All rights reserved. Use of this source code is governed by a
 -- BSD-style license that can be found in the LICENSE file.
 
 tell application "Firefox 29" to activate
 
 delay 3.0
 
 tell application "System Events"
         keystroke "n" using command down
@@ skipping 33 matching lines @@
         key code 125
         key code 125
         key code 125
 
         -- Simulate Cmd-Right.
         key code 124 using command down
 
         -- Simulate Delete
         key code 51
 
+        delay 0.1

[kasperl, 2014/09/03 12:55:18]

I trust this does what you want.

[ahe, 2014/09/03 13:10:22]

Yes. This is for "manual" testing on my Mac.

+        keystroke "a" using command down
+        delay 0.2
+        keystroke "c" using command down
+
+        delay 0.2
+        set clipboardData to (the clipboard as text)
+
+        if ("main() {" is in (clipboardData as string)) then
+                error "main() { in clipboardData"
+        end if
+
+        if ("main() " is not in (clipboardData as string)) then
+                error "main() is not in clipboardData"
+        end if
+
+        keystroke "l" using command down
+        delay 0.2
+
+        keystroke "http://localhost:8080/"
+        -- Simulate Enter key.
+        key code 36
+
+        delay 5.0
+
+        keystroke "l" using command down
+        -- Simulate Tab key.
+        key code 48
+        key code 48
+        key code 48
+        key code 48
+
+        -- Simulate End key.
+        key code 119
+
+        -- Simulate Home key.
+        key code 115
+
+        -- Simulate Tab key.
+        key code 48
+
         -- Simulate Cmd-Down.
-        -- key code 125 using command down
+        key code 125 using command down
+
+        repeat 204 times
+                -- Simulate Delete
+               key code 51
+        end repeat
+
+        delay 5.0
+        repeat 64 times
+                -- Simulate Delete
+               key code 51
+        end repeat
+
+
+        delay 0.1
+        keystroke "a" using command down
+        delay 0.5
+        keystroke "c" using command down
+
+        delay 0.5
+        set clipboardData to (the clipboard as text)
+
+        if ("/" is not (clipboardData as string)) then
+                error "/ is not clipboardData"
+        end if
 
 end tell
+
+tell application "Firefox" to quit
+
+display notification "Test passed" with title "Firefox test" sound name "Glass"