Testing Extensions

Array+Extensions.swift

import Foundation

extension Array where Element == String {
	func merged(into existingArray: [Element]) -> [Element] {
		var index = Set(existingArray.map { $0.lowercased() })
		var container = existingArray
		forEach {
			if !index.contains($0.lowercased()) {
				container.insert($0, at: container.startIndex)
				index.insert($0)
			}
		}
		return container
	}
}

Array+ExtensionsTests.swift

import XCTest
@testable import Shopify_POS

class ArrayExtensionsTests: XCTestCase {
	func testMergeRemovesDifferentCaseDuplicates() {
		let newWords = ["COUCH", "bed", "TaBlE"]
		let existingWords = ["couch", "BED"]
		let expectedMerged = ["TaBlE", "couch", "BED"]
		
		let merged = newWords.merged(into: existingWords)
		XCTAssertEqual(merged, expectedMerged)
	}
}