injectable-time

injectable-time is a library to support dependency-injecting a time source.

It provides a trait TimeSource with one function, now().

It provides two structs, UtcTime and FakeTime, which implement TimeSource. FakeTime has a function set which can be used in tests.

The now() function of UtcTime returns the number of nanoseconds since the Unix epoch. The library uses i64 instead of an os-dependent time type so it can run host-side and in Fuchsia.

Any struct that needs an injectable time source can store a &'a dyn TimeSource. Note the lack of mut.

See the unit tests in injectable_time.rs for a usage example.

Building

This project should be automatically included in builds.

Using

injectable-time can be used by depending on the //src/diagnostics/lib/util/injectable-time gn target and then using the injectable-time crate in a rust project.

injectable-time is not available in the sdk and is intended to be used only by diagnostics binaries.

Testing

Unit tests for injectable-time are available in the injectable-time package:

$ fx test injectable_time_lib_test

You'll need to include //src/diagnostics/lib/injectable-time:tests in your build, either by using fx args to put it under universe_package_labels, or by fx set [....] --with //src/diagnostics/lib/injectable-time:tests. format