         stringEvent.post("input")
         subscriber = nil
         XCTAssert(ran == true, "subscription didn't run")
-        XCTAssertNil(subscriber, "subscriber should be nil -- This is obvious, but silences 'variable not read' warning")
+        let msg = "subscriber must be nil -- silences 'variable not read' warning"
+        XCTAssertNil(subscriber, msg)
     }
 }

        }
        emptyEvent.post()
    }
    
    func testInputAndEventRun() {
        let stringEvent = Event<String>()
        var ran = false

class EventTests: XCTestCase {
    static var allTests: [(String, EventTests -> () throws -> Void)] {
        return [
            ("testEventRemovedOnSubscriptionDeallocation",
             testEventRemovedOnSubscriptionDeallocation),
            ("testInputAndEventRun",
             testInputAndEventRun)
        ]
    }

    func testEventRemovedOnSubscriptionDeallocation() {
        let emptyEvent = Event<Void>()
        let _ = emptyEvent.subscribe {
