import XCTest
@testable import FocusFixer

final class DebounceTests: XCTestCase {
    func testFirstEventIsAlwaysProcessed() {
        var clockValue: TimeInterval = 0
        var debouncer = Debouncer(interval: 0.15, clock: { clockValue })
        XCTAssertTrue(debouncer.shouldProcess())
    }

    func testEventWithinIntervalIsSuppressed() {
        var clockValue: TimeInterval = 0
        var debouncer = Debouncer(interval: 0.15, clock: { clockValue })
        XCTAssertTrue(debouncer.shouldProcess())

        clockValue += 0.05
        XCTAssertFalse(debouncer.shouldProcess())
    }

    func testEventAfterIntervalIsProcessed() {
        var clockValue: TimeInterval = 0
        var debouncer = Debouncer(interval: 0.15, clock: { clockValue })
        XCTAssertTrue(debouncer.shouldProcess())

        clockValue += 0.2
        XCTAssertTrue(debouncer.shouldProcess())
    }

    func testAcceptedEventResetsTheWindow() {
        var clockValue: TimeInterval = 0
        var debouncer = Debouncer(interval: 0.15, clock: { clockValue })
        XCTAssertTrue(debouncer.shouldProcess())

        clockValue += 0.2
        XCTAssertTrue(debouncer.shouldProcess())

        clockValue += 0.05
        XCTAssertFalse(debouncer.shouldProcess())
    }
}