---
name: "Test::Future::Deferred"
section: "3pm"
platform: "linux"
package: "libfuture-perl"
version: "0.51-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Test::Future::Deferred"
---

# Test::Future::Deferred(3pm)

a future which completes later

## NAME

"Test::Future::Deferred" - a future which completes later

## SYNOPSIS

```
   my $future = Test::Future::Deferred->done_later( 1, 2, 3 );
   # Future is not ready yet
   my @result = $future->get;
```

## DESCRIPTION

This subclass of Future provides two new methods and an implementation of the `"await"` interface, which allows the futures to appear pending at first, but then to complete when `"get"` is called at the toplevel on one of them.

This behaviour is useful in unit tests to check that behaviour of a module under test is correct even with non-immediate futures, as it allows a future to easily be constructed that will complete "soon", but not yet, without needing an event loop.

Because these futures provide their own `"await"` method, they shouldn't be mixed in the same program with other kinds of futures from real event systems or similar.

## METHODS

### done\_later

```
   $f->done_later( @args );
```

Equivalent to invoking the regular `"done"` method as part of the `"await"` operation called on the toplevel future. This makes the future complete with the given result, but only when `"get"` is called.

### fail\_later

```
   $f->fail_later( $message, $category, @details );
```

Equivalent to invoking the regular `"fail"` method as part of the `"await"` operation called on the toplevel future. This makes the future complete with the given failure, but only when `"get"` is called. As the `"failure"` method also waits for completion of the future, then it will return the failure message given here also.

## AUTHOR

Paul Evans \<leonerd@leonerd.org.uk\>