Code style improvements + added some tests for IntegerInputFormatter with just the minus sign.

Author: pmusolino

WooCommerce/Classes/Tools/UnitInputFormatter/IntegerInputFormatter.swift

@@ -8,6 +8,8 @@ struct IntegerInputFormatter: UnitInputFormatter {
     ///
     let defaultValue: String
 
+    private let minus: Character = "-"
+
     private let numberFormatter: NumberFormatter = {
         let numberFormatter = NumberFormatter()
         numberFormatter.allowsFloats = false
@@ -19,7 +21,7 @@ struct IntegerInputFormatter: UnitInputFormatter {
             // Allows empty input to be replaced by defaultValue
             return true
         }
-        return numberFormatter.number(from: input) != nil || input == "-"
+        return numberFormatter.number(from: input) != nil || input == String(minus)
     }
 
     func format(input text: String?) -> String {
@@ -29,8 +31,7 @@ struct IntegerInputFormatter: UnitInputFormatter {
 
         var formattedText = numberFormatter.number(from: text)?.stringValue ?? defaultValue
 
-        // The minus sign is mantained if present
-        let minus: Character = "-"
+        // The minus sign is maintained if present
         if text.first == minus {
             formattedText = String(minus) + formattedText.replacingOccurrences(of: "-", with: "")
         }

WooCommerce/WooCommerceTests/Tools/IntegerInputFormatterTests.swift

@@ -3,7 +3,7 @@ import XCTest
 @testable import WooCommerce
 
 final class IntegerInputFormatterTests: XCTestCase {
-    private let formatter = IntegerInputFormatter(defaultValue: "0")
+    private let formatter = IntegerInputFormatter(defaultValue: "1")
 
     // MARK: test cases for `isValid(input:)`
 
@@ -37,11 +37,16 @@ final class IntegerInputFormatterTests: XCTestCase {
         XCTAssertTrue(formatter.isValid(input: input))
     }
 
+    func testMinusSignInputIsValid() {
+        let input = "-"
+        XCTAssertTrue(formatter.isValid(input: input))
+    }
+
     // MARK: test cases for `format(input:)`
 
     func testFormattingEmptyInput() {
         let input = ""
-        XCTAssertEqual(formatter.format(input: input), "0")
+        XCTAssertEqual(formatter.format(input: input), "1")
     }
 
     func testFormattingInputWithLeadingZeros() {
@@ -58,4 +63,14 @@ final class IntegerInputFormatterTests: XCTestCase {
         let input = "-3412424214"
         XCTAssertEqual(formatter.format(input: input), "-3412424214")
     }
+
+    func testFormattingMinusSignInput() {
+        let input = "-"
+        XCTAssertEqual(formatter.format(input: input), "-1")
+    }
+
+    func testFormattingMultipleMinusSignInput() {
+        let input = "--"
+        XCTAssertEqual(formatter.format(input: input), "-1")
+    }
 }