     func testAverageDecayedBGReadingQuantityBgReadings50at50then50at150() {
 
         let endDate = Date()
-        let bgReadings = BGReadingTestHelper.bgReadings50at50then50at150(endDate) as! [BGReading]
-        XCTAssertEqual(bgReadings.count, 100)
-        let bgReadingLights = TrendsAlgorithmModel.bgReadingLights(bgReadings: bgReadings)
+        let bgReadingLights = BGReadingLightsHelper.bgReadingLights50at50then50at150(endDate: endDate)
+        XCTAssertEqual(bgReadingLights.count, 100)
 
         // call method under test
         let actual = TrendsAlgorithmModel.averageDecayedBGReadingQuantity(bgReadingLights,

        let bgReadingLights = TrendsAlgorithmModel.bgReadingLights(bgReadings: bgReadings)
        XCTAssertEqual(bgReadingLights.count, bgReadings.count)
    }
    
    // MARK: - test averageDecayedBGReadingQuantity

    func testAverageDecayedBGReadingQuantity200EndDateNow() {

        let actual = TrendsAlgorithmModel.averageDecayedBGReadingQuantity(bgReadingLights,
                                                                          date: endDate,
                                                                          decayLifeSeconds: TrendsAlgorithmModel.hemoglobinLifespanSeconds)

        let expected: Float = 59.394 / MG_PER_DL_PER_MMOL_PER_L
        let accuracy: Float = 0.1
        XCTAssertEqualWithAccuracy(actual, expected, accuracy: accuracy)
