Writing tests for the JournalEntry class

As you have seen, the initializer for the JournalEntry class will only return a JournalEntry instance if title and body are not empty, and rating is between 0 and 5 inclusive. If these conditions are not met, the initializer will return nil. To test this, you will write tests to confirm that a valid JournalEntry instance is created when the above conditions are met, and nil is returned when they are not. Follow these steps:

1. Click the JRNLTests file inside the JRNLTests folder in the Project navigator.
2. Modify the contents of this file as follows:

   import Testing
   @testable import JRNL
    
   struct JRNLTests {
    
     @Test func JournalEntryInitializationSucceeds() {
       let zeroRatingJournalEntry = JournalEntry(rating: 0,    title: "Zero", body: "Zero rating entry")
       #expect(zeroRatingJournalEntry != nil)
           
       let positiveRatingJournalEntry = JournalEntry(    rating: 5, title: "Highest&quot...