R: The building block of all 'expect_' functions

expect {testthat} | R Documentation

## The building block of all `expect_` functions

### Description

Call `expect()` when writing your own expectations. See `vignette("custom-expectation")` for details.

### Usage

    expect(ok, failure_message, info = NULL, srcref = NULL, trace = NULL)

### Arguments

`ok` | `TRUE` or `FALSE` indicating if the expectation was successful.
`failure_message` | Message to show if the expectation failed.
`info` | Character vector continuing additional information. Included for backward compatibility only and new expectations should not use it.
`srcref` | Location of the failure. Should only needed to be explicitly supplied when you need to forward a srcref captured elsewhere.
`trace` | An optional backtrace created by `rlang::trace_back()`. When supplied, the expectation is displayed with the backtrace.

### Details

While `expect()` creates and signals an expectation in one go, `exp_signal()` separately signals an expectation that you have manually created with `new_expectation()`. Expectations are signalled with the following protocol:

- If the expectation is a failure or an error, it is signalled with `base::stop()`. Otherwise, it is signalled with `base::signalCondition()`.

- The `continue_test` restart is registered. When invoked, failing expectations are ignored and normal control flow is resumed to run the other tests.

### Value

An expectation object. Signals the expectation condition with a `continue_test` restart.

### See Also

`exp_signal()`

[Package testthat version 2.3.2 Index]