Check scenario

CheckScenario.swift

func checkScenario(_ scenario: Scenario) {
    let filter = KalmanFilter()

    // Add up the distance between each location in the true path
    let trueDist = unfilteredDistance(scenario.truePath)
    
    // Add up the distance between each location in the noisy path
    let unfilteredDist = unfilteredDistance(scenario.noisyPath)
    
    // Add up the distance between each location in the noisy path
    // AFTER applying the Kalman Filter we created earlier
    let filteredDist = filteredDistance(scenario.noisyPath, using: filter)

    let unfilteredErrorRate = abs(trueDist - unfilteredDist) / trueDist
    let filteredErrorRate = abs(trueDist - filteredDist) / trueDist

    XCTAssertLessThanOrEqual(filteredErrorRate, scenario.minAllowableError,
                             "GPS filtering did not meet accuracy threshold [\(scenario.description)]")
    XCTAssertLessThanOrEqual(filteredErrorRate, unfilteredErrorRate,
                             "GPS filtering performed worse than raw data [\(scenario.description)]")
}