Add test case for truncation of cmdline signatures

test/signatures.vim

@@ -53,6 +53,39 @@ describe 'signatures'
         Expect msg == "\n"
     end
 
+    it 'command line truncation'
+        let g:jedi#show_call_signatures = 2
+        call jedi#configure_call_signatures()
+
+        function! Signature()
+            redir => msg
+            Python jedi_vim.show_call_signatures()
+            redir END
+            return msg
+        endfunction
+
+        let funcname = repeat('a', &columns - 30)
+        put = 'def '.funcname.'(arg1, arg2, arg3, a, b, c):'
+        put = '    pass'
+        execute "normal o".funcname."( "
+        Expect Signature() == "\n".funcname."(arg1, ...)"
+
+        normal sarg1, 
+        Expect Signature() == "\n".funcname."(..., arg2, ...)"
+
+        normal sarg2, arg3, 
+        Expect Signature() == "\n".funcname."(..., a, b, c)"
+
+        normal sa, b, 
+        Expect Signature() == "\n".funcname."(..., c)"
+
+        g/^/d
+        put = 'def '.funcname.'('.repeat('b', 20).', arg2):'
+        put = '    pass'
+        execute "normal o".funcname."( "
+        Expect Signature() == "\n".funcname."(...)"
+    end
+
     it 'command line no signature'
         let g:jedi#show_call_signatures = 2
         call jedi#configure_call_signatures()