Make reserveCapacity values more readable & test fixes

Author: David Dunn

Foundation/NSJSONSerialization.swift

@@ -284,6 +284,8 @@ internal extension JSONSerialization {
 //MARK: - JSONSerializer
 private struct JSONWriter {
 
+    private let maxUIntLength = String(describing: UInt.max).characters.count
+    private let maxIntLength = String(describing: Int.max).characters.count
     var indent = 0
     let pretty: Bool
     let writer: (String?) -> Void
@@ -334,8 +336,8 @@ private struct JSONWriter {
         var array: [UInt] = []
         var stringResult = ""
         //Maximum length of an UInt
-        array.reserveCapacity(20)
-        stringResult.reserveCapacity(20)
+        array.reserveCapacity(maxUIntLength)
+        stringResult.reserveCapacity(maxUIntLength)
         var number = value
 
         while number != 0 {
@@ -375,10 +377,9 @@ private struct JSONWriter {
         }
         var array: [Int] = []
         var stringResult = ""
-        //Maximum length of an Int
-        array.reserveCapacity(19)
+        array.reserveCapacity(maxIntLength)
         //Account for a negative sign
-        stringResult.reserveCapacity(20)
+        stringResult.reserveCapacity(maxIntLength + 1)
         var number = value
 
         while number != 0 {

TestFoundation/TestNSJSONSerialization.swift

@@ -1060,22 +1060,22 @@ extension TestNSJSONSerialization {
 
     func test_serialize_IntMax() {
         let json: [Any] = [Int.max]
-        XCTAssertEqual(try trySerialize(json), "[9223372036854775807]")
+        XCTAssertEqual(try trySerialize(json), "[\(Int.max)]")
     }
 
     func test_serialize_IntMin() {
         let json: [Any] = [Int.min]
-        XCTAssertEqual(try trySerialize(json), "[-9223372036854775808]")
+        XCTAssertEqual(try trySerialize(json), "[\(Int.min)]")
     }
 
     func test_serialize_UIntMax() {
         let json: [Any] = [UInt.max]
-        XCTAssertEqual(try trySerialize(json), "[18446744073709551615]")
+        XCTAssertEqual(try trySerialize(json), "[\(Int.max)]")
     }
 
     func test_serialize_UIntMin() {
         let json: [Any] = [UInt.min]
-        XCTAssertEqual(try trySerialize(json), "[0]")
+        XCTAssertEqual(try trySerialize(json), "[\(Int.min)]")
     }
 
     func test_serialize_stringEscaping() {