asserterror

A keyword that can be used in Scripting, to test whether an expected erroe message is indeed generated.

## Examples

`asserterror Unknown variable
` `a = 2 * b + 3
`

The line `a = 2 * b + 3` contains the unknown variable `b`. Therefore, the script would normally issue an error message like

`Unknown variable:
` `« a = 2 * b
` `
` `Script line 2 not performed or completed:
` `« a = 2 * b + 3 »
` `Menu command “Run” not completed.
`

The line with `asserterror` prevents the error message from being popped up, and instead checks that the error message contains the string “Unknown variable”, which it does.

This one works differently:

`b = 4
` `asserterror Unknown variable
` `a = 2 * b + 3
`

In this case the expected error message does not occur, and the script exits with the following error message:

`Script assertion fails in line 2: error « Unknown variable » not raised.
` `Instead: no error.
` `
` `Script line 3 not performed or completed:
` `« a = 2 * b + 3 »
` `Menu command “Run” not completed.
`

Another case:

`asserterror What is blabla
` `a = Create Sound from blabla: 1, 2, 3
`

In this case a different error message than the expected error message occurs, and the script exits with the following error message:

`Script assertion fails in line 1: error « What is blabla » not raised.
` `Instead: Command “Create Sound from blabla:” not available for current selection.
` `
` `Script line 2 not performed or completed:
` `« a = Create Sound from blabla: 1, 2, 3 »
` `Menu command “Run” not completed.
`

### Links to this page

- `padLeft$`
- `padOrTruncateLeft$`
- `padOrTruncateRight$`
- `padRight$`
- `truncateLeft$`
- `truncateRight$`
- Functions