Unit Test

[mazingyu]

Pass: invalidhost is reachable - Reachability.Reachability

[mazingyu]

`
func testValidHost() {
let validHostName = "invalidhost"

    guard let reachability = try? Reachability(hostname: validHostName) else {
        return XCTFail("Unable to create reachability")
    }
    
    let expected = expectation(description: "Check valid host")
    reachability.whenReachable = { reachability in
        print("Pass: \(validHostName) is reachable - \(reachability)")
        expected.fulfill()
        // Only fulfill the expectation on host reachable
    }
    reachability.whenUnreachable = { reachability in
        print("\(validHostName) is initially unreachable - \(reachability)")
        // Expectation isn't fulfilled here, so wait will time out if this is the only closure called
    }
    
    do {
        try reachability.startNotifier()
    } catch {
        return XCTFail("Unable to start notifier")
    }
    
    waitForExpectations(timeout: 5, handler: nil)
    
    reachability.stopNotifier()
}

`