Swift implementation of five string operations

string_ops.swift

func cleanUp(s: String) -> String {
    return splitIntoSentences(summary: fixHyphenation(s: fixWhitespace(s: s)))[0]
}

func fixHyphenation(s: String) -> String {
    return s.replacingOccurrences(of: "- ", with: "")
}

func fixWhitespace(s: String) -> String {
    return s.replacingOccurrences(of: "\n", with: " ")
}

func splitIntoSentences(summary: String) -> [String] {
    return summary
            .components(separatedBy: ". ")
            .map { ensureEndsWithPeriod(sentence: $0) }
}

func ensureEndsWithPeriod(sentence: String) -> String {
    if let lastCharacter = sentence.characters.last {
        if lastCharacter == "." {
            return sentence
        } else {
            return sentence + "."
        }
    } else {
        return sentence
    }
}

string_ops_test.swift

import XCTest

class Tests: XCTestCase {
    func testFixHyphenation() {
        XCTAssertEqual( fixHyphenation(s: "auto- mobile"), "automobile" )
    }
    
    func testFixWhitespace() {
        XCTAssertEqual( fixWhitespace(s: "and\nthe story"), "and the story" )
    }
    
    func testCleanUp() {
        let input = "Relating to the state transient lodging tax; creating\nnew provisions; amending ORS 284.131 and\n320.305; prescribing an effective date; and pro-\nviding for revenue raising that requires approval\nby a three-fifths majority.\nWhereas Enrolled House Bill 2267 (chapter 818,"
        let expected_output = "Relating to the state transient lodging tax; creating new provisions; amending ORS 284.131 and 320.305; prescribing an effective date; and providing for revenue raising that requires approval by a three-fifths majority."
        
        XCTAssertEqual( cleanUp(s: input), expected_output )
    }   
}