modify CalibrationsTests so each test is independent

FreeAPSTests/CalibrationsTests.swift

@@ -12,6 +12,9 @@ class CalibrationsTests: XCTestCase, Injectable {
     }
 
     func testCreateSimpleCalibration() {
+        // restore state so each test is independent
+        calibrationService.removeAllCalibrations()
+
         let calibration = Calibration(x: 100.0, y: 102.0)
         calibrationService.addCalibration(calibration)
 
@@ -25,29 +28,22 @@ class CalibrationsTests: XCTestCase, Injectable {
     }
 
     func testCreateMultipleCalibration() {
+        // restore state so each test is independent
+        calibrationService.removeAllCalibrations()
+
         let calibration = Calibration(x: 100.0, y: 120)
         calibrationService.addCalibration(calibration)
 
         let calibration2 = Calibration(x: 120.0, y: 130.0)
         calibrationService.addCalibration(calibration2)
-        // The original 4 XCTAsserts() below fail on the initial run,
-        //    but will work on subsequent runs.
-        // Should fix this stuff to not be stateful so that the
-        //    same results are obtained on each run.
-        // Temporary fix comment out original and use XCTAssertEqual
-        //    which allows an accuracy parameter
-        // XCTAssertTrue(calibrationService.slope == 0.8)
-        // XCTAssertTrue(calibrationService.intercept == 37)
-        // XCTAssertTrue(calibrationService.calibrate(value: 80) == 101)
-
-        XCTAssertEqual(calibrationService.slope, 0.95, accuracy: 0.0001)
-        XCTAssertEqual(calibrationService.intercept, 16, accuracy: 0.0001)
-        XCTAssertEqual(calibrationService.calibrate(value: 80), 92, accuracy: 0.0001)
+
+        XCTAssertEqual(calibrationService.slope, 0.8, accuracy: 0.0001)
+        XCTAssertEqual(calibrationService.intercept, 37, accuracy: 0.0001)
+        XCTAssertEqual(calibrationService.calibrate(value: 80), 101, accuracy: 0.0001)
 
         calibrationService.removeLast()
 
-        // XCTAssertTrue(calibrationService.calibrations.count == 1)
-        XCTAssertEqual(calibrationService.calibrations.count, 2)
+        XCTAssertTrue(calibrationService.calibrations.count == 1)
 
         calibrationService.removeAllCalibrations()
         XCTAssertTrue(calibrationService.calibrations.isEmpty)