TestBed.sociable()

Creates a test environment that mixes real implementations with mocked dependencies for testing interactions between business logic classes.

Signature

TestBed.sociable<T>(targetClass: Type<T>): SociableTestBedBuilder<T>

Parameters

Parameter	Type	Description
targetClass	`Type<T>`	The class constructor to test

Returns

SociableTestBedBuilder<T> with the following configuration method:

.expose() - List classes to keep real. Everything else is mocked.
.mock(dependency) - Configure specific mock behavior before compilation
.compile() - Finalizes configuration and creates the test environment

The `.expose()` Method

expose<D>(dependency: Type<D>): SociableTestBedBuilder<T>

.expose() only accepts class constructors, not string, symbol, or other non-class tokens. Those tokens identify dependencies but do not supply a class implementation for Suites to instantiate. Token dependencies are mocked by default; .mock().final() can instead inject a supplied value or implementation.
.expose() method only controls explicit, injected dependencies. Implicit dependencies (direct imports) are not intercepted by TestBed and will execute as normal.

Example

const { unit, unitRef } = await TestBed.sociable(UserService)
  .expose(UserValidator)  // Only this is real
  .compile();

// Can retrieve non-exposed (mocked)
const database = unitRef.get(Database);

// Cannot retrieve exposed
// const validator = unitRef.get(UserValidator);  // ERROR - it's real

What’s Retrievable

With .expose():

✅ Non-exposed dependencies (mocked by default)
✅ Tokens (auto-mocked or configured with .impl())
✅ Dependencies configured with .mock().impl()
❌ Exposed dependencies (real, not retrievable)
❌ Values supplied with .mock().final()

See injected dependencies and retrievable mocks for how injection differs from unitRef lookup.