Add helpers for calculating the delta percentage for specific analytics stats

Author: rachelmcr

WooCommerce/Classes/ViewRelated/Dashboard/Factories/StatsV4DataHelper.swift

@@ -24,6 +24,16 @@ final class StatsV4DataHelper {
         }
     }
 
+    /// Creates the text to display for the total revenue delta.
+    ///
+    static func createTotalRevenueDelta(from previousPeriod: OrderStatsV4?, to currentPeriod: OrderStatsV4?, locale: Locale = .current) -> String {
+        if let previousRevenue = totalRevenue(at: nil, orderStats: previousPeriod), let currentRevenue = totalRevenue(at: nil, orderStats: currentPeriod) {
+            return createDeltaText(from: previousRevenue, to: currentRevenue, locale: locale)
+        } else {
+            return Constants.placeholderText
+        }
+    }
+
     // MARK: Orders Stats
 
     /// Creates the text to display for the order count.
@@ -36,6 +46,16 @@ final class StatsV4DataHelper {
         }
     }
 
+    /// Creates the text to display for the order count delta.
+    ///
+    static func createOrderCountDelta(from previousPeriod: OrderStatsV4?, to currentPeriod: OrderStatsV4?, locale: Locale = .current) -> String {
+        if let previousCount = orderCount(at: nil, orderStats: previousPeriod), let currentCount = orderCount(at: nil, orderStats: currentPeriod) {
+            return createDeltaText(from: previousCount, to: currentCount, locale: locale)
+        } else {
+            return Constants.placeholderText
+        }
+    }
+
     /// Creates the text to display for the average order value.
     ///
     static func createAverageOrderValueText(orderStats: OrderStatsV4?, currencyFormatter: CurrencyFormatter, currencyCode: String) -> String {
@@ -48,6 +68,16 @@ final class StatsV4DataHelper {
         }
     }
 
+    /// Creates the text to display for the average order value delta.
+    ///
+    static func createAverageOrderValueDelta(from previousPeriod: OrderStatsV4?, to currentPeriod: OrderStatsV4?, locale: Locale = .current) -> String {
+        if let previousAverage = averageOrderValue(orderStats: previousPeriod), let currentAverage = averageOrderValue(orderStats: currentPeriod) {
+            return createDeltaText(from: previousAverage, to: currentAverage, locale: locale)
+        } else {
+            return Constants.placeholderText
+        }
+    }
+
     // MARK: Views and Visitors Stats
 
     /// Creates the text to display for the visitor count.
@@ -60,6 +90,16 @@ final class StatsV4DataHelper {
         }
     }
 
+    /// Creates the text to display for the visitor count delta.
+    ///
+    static func createVisitorCountDelta(from previousPeriod: SiteVisitStats?, to currentPeriod: SiteVisitStats?, locale: Locale = .current) -> String {
+        if let previousCount = visitorCount(at: nil, siteStats: previousPeriod), let currentCount = visitorCount(at: nil, siteStats: currentPeriod) {
+            return createDeltaText(from: previousCount, to: currentCount, locale: locale)
+        } else {
+            return Constants.placeholderText
+        }
+    }
+
     // MARK: Conversion Stats
 
     /// Creates the text to display for the conversion rate.
@@ -82,12 +122,15 @@ final class StatsV4DataHelper {
             return Constants.placeholderText
         }
     }
+}
+
+extension StatsV4DataHelper {
 
     // MARK: Delta Calculations
 
     /// Creates the text showing the percent change from the previous `Decimal` value to the current `Decimal` value
     ///
-    static func createDeltaText(from previousValue: Decimal, to currentValue: Decimal, locale: Locale = Locale.current) -> String {
+    static func createDeltaText(from previousValue: Decimal, to currentValue: Decimal, locale: Locale = .current) -> String {
         let numberFormatter = NumberFormatter()
         numberFormatter.numberStyle = .percent
         numberFormatter.positivePrefix = numberFormatter.plusSign
@@ -103,7 +146,7 @@ final class StatsV4DataHelper {
 
     /// Creates the text showing the percent change from the previous `Double` value to the current `Double` value
     ///
-    static func createDeltaText(from previousValue: Double, to currentValue: Double, locale: Locale = Locale.current) -> String {
+    static func createDeltaText(from previousValue: Double, to currentValue: Double, locale: Locale = .current) -> String {
         createDeltaText(from: Decimal(previousValue), to: Decimal(currentValue))
     }
 

WooCommerce/WooCommerceTests/ViewRelated/Dashboard/StatsV4DataHelperTests.swift

@@ -63,6 +63,18 @@ final class StatsV4DataHelperTests: XCTestCase {
         XCTAssertEqual(totalRevenue, "$25")
     }
 
+    func test_createTotalRevenueDelta_returns_expected_delta_text() {
+        // Given
+        let previousOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(grossRevenue: 10))
+        let currentOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(grossRevenue: 15))
+
+        // When
+        let totalRevenueDelta = StatsV4DataHelper.createTotalRevenueDelta(from: previousOrderStats, to: currentOrderStats, locale: locale)
+
+        // Then
+        XCTAssertEqual(totalRevenueDelta, "+50%")
+    }
+
     // MARK: Orders Stats
 
     func test_createOrderCountText_returns_expected_order_count() {
@@ -95,6 +107,18 @@ final class StatsV4DataHelperTests: XCTestCase {
         XCTAssertEqual(orderCount, "1")
     }
 
+    func test_createOrderCountDelta_returns_expected_delta_text() {
+        // Given
+        let previousOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(totalOrders: 10))
+        let currentOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(totalOrders: 15))
+
+        // When
+        let orderCountDelta = StatsV4DataHelper.createOrderCountDelta(from: previousOrderStats, to: currentOrderStats, locale: locale)
+
+        // Then
+        XCTAssertEqual(orderCountDelta, "+50%")
+    }
+
     func test_createAverageOrderValueText_does_not_return_decimal_points_for_integer_value() {
         // Given
         let orderStats = OrderStatsV4.fake().copy(totals: .fake().copy(averageOrderValue: 62))
@@ -121,6 +145,18 @@ final class StatsV4DataHelperTests: XCTestCase {
         XCTAssertEqual(averageOrderValue, "$62.86")
     }
 
+    func test_createAverageOrderValueDelta_returns_expected_delta_text() {
+        // Given
+        let previousOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(averageOrderValue: 10.00))
+        let currentOrderStats = OrderStatsV4.fake().copy(totals: .fake().copy(averageOrderValue: 15.00))
+
+        // When
+        let averageOrderValueDelta = StatsV4DataHelper.createAverageOrderValueDelta(from: previousOrderStats, to: currentOrderStats, locale: locale)
+
+        // Then
+        XCTAssertEqual(averageOrderValueDelta, "+50%")
+    }
+
     // MARK: Views and Visitors Stats
 
     // This test reflects the current method for computing total visitor count.
@@ -151,6 +187,18 @@ final class StatsV4DataHelperTests: XCTestCase {
         XCTAssertEqual(visitorCount, "17")
     }
 
+    func test_createVisitorCountDelta_returns_expected_delta_text() {
+        // Given
+        let previousSiteStats = SiteVisitStats.fake().copy(items: [.fake().copy(period: "0", visitors: 10)])
+        let currentSiteStats = SiteVisitStats.fake().copy(items: [.fake().copy(period: "0", visitors: 15)])
+
+        // When
+        let visitorCountDelta = StatsV4DataHelper.createVisitorCountDelta(from: previousSiteStats, to: currentSiteStats, locale: locale)
+
+        // Then
+        XCTAssertEqual(visitorCountDelta, "+50%")
+    }
+
     // MARK: Conversion Stats
 
     func test_createConversionRateText_returns_placeholder_when_visitor_count_is_zero() {