Adding a lone, upstream completion case to CombineExt’s WithLatestFromTests.swift

with_latest_from_tests.swift

final class WithLatestFromTests: XCTestCase {
	// …

	func testWithLatestFromCompletion() {
		let subject1 = PassthroughSubject<Int, Never>()
		let subject2 = PassthroughSubject<String, Never>()
		var results = [String]()
		var completed = false

		subscription = subject1
			.withLatestFrom(subject2)
			.sink(
				receiveCompletion: { _ in completed  = true },
				receiveValue: { results.append($0) }
			)

		subject1.send(completion: .finished)
		XCTAssertTrue(completed) // ❌ “`XCTAssertTrue` failed.”
		XCTAssertTrue(results.isEmpty)
	}

	// Tests for other arities.

	func testWithLatestFrom2Completion() {}
	func testWithLatestFrom3Completion() {}
}