Created SerializerTests test suite with .testSyncSerialize and .testMeasuerSyncSerializer cases

Tests/CSVTests/SerializerTests.swift

@@ -0,0 +1,98 @@
+import XCTest
+import CSV
+
+final class SerializerTests: XCTestCase {
+    func testSyncSerialize() {
+        let serializer = SyncSerializer()
+        let serialized = serializer.serialize(data)
+        let string = String(decoding: serialized, as: UTF8.self)
+
+        let expected = """
+        "first name","last_name","age","gender","tagLine"
+        "Caleb","Kleveter","18","M","😜"
+        "Benjamin","Franklin","269","M","A penny saved is a penny earned"
+        "Doc","Holliday","174","M","Bang"
+        "Grace","Hopper","119","F",""
+        "Anne","Shirley","141","F","God's in His heaven,
+        all's right with the world"
+        "TinTin","","16","M","Great snakes!"
+        """
+
+        XCTAssertEqual(string, expected)
+    }
+
+    func testMeasuerSyncSerializer() {
+        let serializer = SyncSerializer()
+
+        // 6.268
+        measure {
+            for _ in 0..<100_000 {
+                _ = serializer.serialize(data)
+            }
+        }
+    }
+}
+
+fileprivate let data: OrderedKeyedCollection = [
+    "first name": ["Caleb", "Benjamin", "Doc", "Grace", "Anne", "TinTin"],
+    "last_name": ["Kleveter", "Franklin", "Holliday", "Hopper", "Shirley", nil],
+    "age": ["18", "269", "174", "119", "141", "16"],
+    "gender": ["M", "M", "M", "F", "F", "M"],
+    "tagLine": [
+        "😜", "A penny saved is a penny earned", "Bang", nil,
+        "God's in His heaven,\nall's right with the world", "Great snakes!"
+    ]
+]
+
+//fileprivate let chunks: [OrderedKeyedCollection<String, Array<String?>] = [
+//    "first name,last_name,age",
+//    ",gender,tagLine\nCaleb,Kleveter,18,M,",
+//    "😜\r\nBenjamin,Franklin,269,M,A penny saved is a ",
+//    "penny earned\n\"",
+//    #"Doc","Holliday","174","M",Bang\#r\#n"#,
+//    "Grace,Hopper,119,F,",
+//    #"\#nAnne,Shirley,141,F,"God's in His heaven,\#n"#,
+//    #"all's right with the world""#,
+//    "\nTinTin,,16,M,Great snakes!"
+//]
+
+internal struct OrderedKeyedCollection<K, V>: KeyedCollection, ExpressibleByDictionaryLiteral where K: Hashable {
+    typealias Index = Int
+    typealias Element = (key: Key, value: Value)
+
+    typealias Key = K
+    typealias Keys = Array<K>
+
+    typealias Value = V
+    typealias Values = Array<V>
+
+    private(set) var keys: Array<K>
+    private(set) var values: Array<V>
+
+    var startIndex: Int {
+        return self.keys.startIndex
+    }
+
+    var endIndex: Int {
+        return self.keys.endIndex
+    }
+
+    init(dictionaryLiteral elements: (Key, Value)...) {
+        self.keys = elements.map { $0.0 }
+        self.values = elements.map { $0.1 }
+    }
+
+    subscript(position: Int) -> (key: K, value: V) {
+        get {
+            return (self.keys[position], self.values[position])
+        }
+        set {
+            self.keys[position] = newValue.key
+            self.values[position] = newValue.value
+        }
+    }
+
+    func index(after i: Int) -> Int {
+        return self.keys.index(after: i)
+    }
+}