Revise custom-set tests to comply with problem-spec

exercises/custom-set/Sources/CustomSet/CustomSetExample.swift

@@ -1,8 +1,3 @@
-func == <T> (lh: CustomSet<T>, rh: CustomSet<T>) -> Bool {
-    return lh.contents.keys.sorted { $0.hashValue < $1.hashValue } == rh.contents.keys.sorted { $0.hashValue < $1.hashValue }
-
-}
-
 extension CustomSet where T: Comparable {
 
     var toSortedArray: [Element] { return Array(contents.keys.sorted { $0 < $1 }) }
@@ -14,15 +9,29 @@ struct CustomSet<T: Hashable>: Equatable {
 
     fileprivate var contents = [Element: Bool]()
 
+    var isEmpty: Bool { return contents.count == 0 }
     var size: Int { return contents.count }
 
     init<S: Sequence>(_ sequence: S) where S.Iterator.Element == Element {
         self.contents = [:]
         _ = sequence.map { self.contents[$0] = true }
     }
-    mutating func put(_ item: Element) {
-        contents[item] = true
 
+    static func == <T>(lh: CustomSet<T>, rh: CustomSet<T>) -> Bool {
+        return lh.size == rh.size &&
+            lh.contents.keys.sorted { $0.hashValue < $1.hashValue } ==
+            rh.contents.keys.sorted { $0.hashValue < $1.hashValue }
+    }
+
+    func contains(_ item: Element) -> Bool {
+        if contents[item] != nil {
+            return true
+        }
+        return false
+    }
+
+    mutating func add(_ item: Element) {
+        contents[item] = true
     }
 
     mutating func delete(_ item: Element) {
@@ -35,20 +44,22 @@ struct CustomSet<T: Hashable>: Equatable {
 
     }
 
-    func intersection(_ item: CustomSet) -> CustomSet {
-        var temp = [Element: Bool]()
-        for each in Array(item.contents.keys) {
-            guard contents[each] != nil else { continue }
-            temp[each] = true
+    func intersection(_ other: CustomSet) -> CustomSet {
+        var intersect = CustomSet([Element]())
+        for elem in Array(other.contents.keys) {
+            guard contents[elem] != nil else { continue }
+            intersect.add(elem)
         }
-        return CustomSet(temp.keys)
+        return intersect
     }
-    func difference(_ item: CustomSet) -> CustomSet {
-        var temp = contents
-        for each in Array(item.contents.keys) {
-            temp[each] = nil
+
+    func difference(_ other: CustomSet) -> CustomSet {
+        var diff = CustomSet([Element]())
+        for elem in Array(contents.keys) {
+            guard other.contents[elem] != true else { continue }
+            diff.add(elem)
         }
-        return CustomSet(temp.keys)
+        return diff
     }
 
     func union(_ item: CustomSet) -> CustomSet {
@@ -58,25 +69,22 @@ struct CustomSet<T: Hashable>: Equatable {
         }
         return CustomSet(temp.keys)
     }
-    func isSupersetOf (_ item: CustomSet) -> Bool {
-
-        return item.contents.count == item.contents.filter { self.contents.keys.contains($0.0) }.count
-
-    }
-    func isDisjoint(_ item: CustomSet) -> Bool {
 
-        for each in Array(item.contents.keys) {
-            if contents.keys.contains(each) {
+    func isSubsetOf(_ other: CustomSet) -> Bool {
+        for elem in Array(self.contents.keys) {
+            if !other.contents.keys.contains(elem) {
                 return false
             }
         }
         return true
     }
 
-    func containsMember(_ item: Element) -> Bool {
-        if contents[item] != nil {
-            return true}
-        return false
+    func isDisjoint(_ item: CustomSet) -> Bool {
+        for elem in Array(item.contents.keys) {
+            if contents.keys.contains(elem) {
+                return false
+            }
+        }
+        return true
     }
-
 }