Write unit tests for CGPoint+Extension.swift (#100)

- write unit tests for CGPoint+Extension.swift
- clean up formatting on CGPoint+Extension.swift

Sources/SwiftUICharts/Base/Extensions/CGPoint+Extension.swift

@@ -19,14 +19,14 @@ extension CGPoint {
         if let minPoint = data.min(), let maxPoint = data.max(), minPoint != maxPoint {
             min = minPoint
             max = maxPoint
-        }else {
+        } else {
             return .zero
         }
         if let min = min, let max = max, min != max {
-            if (min <= 0){
-                stepHeight = (frame.size.height-padding) / CGFloat(max - min)
-            }else{
-                stepHeight = (frame.size.height-padding) / CGFloat(max + min)
+            if (min <= 0) {
+                stepHeight = (frame.size.height - padding) / CGFloat(max - min)
+            } else {
+                stepHeight = (frame.size.height - padding) / CGFloat(max + min)
             }
         }
 

Tests/SwiftUIChartsTests/CGPointExtensionTests.swift

@@ -0,0 +1,32 @@
+//
+//  CGPointExtensionTests.swift
+//  SwiftUIChartsTests
+//
+//  Created by Adrian Bolinger on 5/24/20.
+//
+
+@testable import SwiftUICharts
+import XCTest
+
+class CGPointExtensionTests: XCTestCase {
+    static let twentyElementArray: [Double] = Array(repeating: Double.random(in: 1...100), count: 20)
+    
+    func testGetStepWithOneElementArray() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let oneElementArray: [Double] = [0.0]
+        
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: oneElementArray), .zero)
+    }
+    
+    func testGetStepWithMultiElementArrayWithNegativeValues() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let multiElementArray: [Double] = [-5.0, 0.0, 5.0]
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: multiElementArray), CGPoint(x: 150.0, y: 27.0))
+    }
+    
+    func testGetStepWithMultiElementArrayWithPositiveValues() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let multiElementArray: [Double] = [5.0, 10.0, 15.0]
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: multiElementArray), CGPoint(x: 150.0, y: 13.5))
+    }
+}