   expectFalse(s.contains(.wednesday))
   expectFalse(s.contains(.thursday))
   expectFalse(s.contains(.saturday))
-  (s.contains(.friday))
+  expectTrue(s.contains(.friday))
 }
 
 OptionSetTests.test("Contains.MultipleOptions") {
   let s: Days = [.monday, .tuesday, .wednesday, .thursday, .friday]
   
   expectFalse(s.contains(.sunday))
-  (s.contains(.monday))
-  (s.contains(.tuesday))
-  (s.contains(.wednesday))
-  (s.contains(.thursday))
-  (s.contains(.friday))
+  expectTrue(s.contains(.monday))
+  expectTrue(s.contains(.tuesday))
+  expectTrue(s.contains(.wednesday))
+  expectTrue(s.contains(.thursday))
+  expectTrue(s.contains(.friday))
   expectFalse(s.contains(.saturday))
 }
 

OptionSetTests.test("IsEmpty.EmptySet") {
  var s: Days = []
  
  (s.isEmpty)
  
  s.insert(.monday)
  

  let s2: Days = [.monday, .tuesday, .wednesday]

  s1.formSymmetricDifference(s2)
  expectTrue(s1.contains(.wednesday))
  expectFalse(s1.contains(.thursday))
}

