`withDefault` is a type helper that allows to create a type that
defaults to a default value when trying to decode a nullish value.
That type was not correctly working with boolean types, causing `false`
values to be replaced by true. This would specifically cause issues when
parsing the target state, where a `running: false` in a service would
become a `running: true` due to the type decoding.
Change-type: patch
The supervisor uses the following pattern for async module
initialization
```typescript
// module.ts
export const initialised = (async () => {
// do some async initialization
})();
// somewhere else
import * as module from 'module';
async function setup() {
await module.initialise;
}
```
The above pattern means that whenever the module is imported, the
initialisation procedure will be ran, which is an anti-pattern.
This converts any instance of this pattern into a function
```typescript
export const initialised = _.once(async () => {
// do some async initialization
});
```
And anywhere else on the code it replaces the call with a
```typescript
await module.initialised();
```
Change-type: patch
This sets up the new `test/unit` and `test/integration` folders
and starts classification of some of the test files.
Note that unit tests include, `fs-utils` and `system-info` tests.
While these tests interact with the filesystem, the implementation
of these modules is simple enough, and the tests are fast enough to
allow these tests to fall under the `unit` test category (according to
test/README)
Change-type: patch
We are refactoring the supervisor test suite into unit tests (for
algorithms an domain model tests) and integration
tests (for interaction with out-of-process dependencies).
This means the current test suite needs to be classified into
these two categories, and fixed whenever possible.
This commit moves the test suite under the `test/legacy` folder, this
folder should be progressively migrated and eventually removed.
Subsequent commits will begin to split these files into unit and
integration whenever possible.
Depends-on: #1996
Change-type: patch
