added tests for isEmpty / isNotEmpty

lib/src/ilist/ilist.dart

@@ -18,7 +18,7 @@ import "l_flat.dart";
 @immutable
 class IListEmpty<T> // ignore: must_be_immutable
     extends IList<T> {
-  /// Creates a empty list. In most cases, you should use `const IList.empty()`.
+  /// Creates an empty list. In most cases, you should use `const IList.empty()`.
   ///
   /// IMPORTANT: You must always use the `const` keyword.
   /// It's always wrong to use an `IListEmpty()` which is not constant.
@@ -29,14 +29,22 @@ class IListEmpty<T> // ignore: must_be_immutable
   @override
   final ConfigList config;
 
-  /// A empty list is always flushed, by definition.
+  /// An empty list is always flushed, by definition.
   @override
   bool get isFlushed => true;
 
   /// Nothing happens when you flush a empty list, by definition.
   @override
   IListEmpty<T> get flush => this;
 
+  /// An empty list is always empty, by definition
+  @override
+  bool get isEmpty => true;
+
+  /// An empty list is always empty, by definition
+  @override
+  bool get isNotEmpty => false;
+
   @override
   int get _counter => 0;
 

lib/src/imap/imap.dart

@@ -19,7 +19,7 @@ import "m_replace.dart";
 @immutable
 class IMapEmpty<K, V> // ignore: must_be_immutable
     extends IMap<K, V> {
-  /// Creates a empty map. In most cases, you should use `const IMap.empty()`.
+  /// Creates an empty map. In most cases, you should use `const IMap.empty()`.
   ///
   /// IMPORTANT: You must always use the `const` keyword.
   /// It's always wrong to use an `IMapEmpty()` which is not constant.
@@ -30,14 +30,22 @@ class IMapEmpty<K, V> // ignore: must_be_immutable
   @override
   final ConfigMap config;
 
-  /// A empty map is always flushed, by definition.
+  /// An empty map is always flushed, by definition.
   @override
   bool get isFlushed => true;
 
   /// Nothing happens when you flush a empty map, by definition.
   @override
   IMapEmpty<K, V> get flush => this;
 
+  /// An empty map is always empty, by definition
+  @override
+  bool get isEmpty => true;
+
+  /// An empty map is always empty, by definition
+  @override
+  bool get isNotEmpty => false;
+
   @override
   int get _counter => 0;
 

lib/src/iset/iset.dart

@@ -18,7 +18,7 @@ import "s_flat.dart";
 @immutable
 class ISetEmpty<T> // ignore: must_be_immutable
     extends ISet<T> {
-  /// Creates a empty set. In most cases, you should use `const ISet.empty()`.
+  /// Creates an empty set. In most cases, you should use `const ISet.empty()`.
   ///
   /// IMPORTANT: You must always use the `const` keyword.
   /// It's always wrong to use an `ISetEmpty()` which is not constant.
@@ -29,14 +29,22 @@ class ISetEmpty<T> // ignore: must_be_immutable
   @override
   final ConfigSet config;
 
-  /// A empty set is always flushed, by definition.
+  /// An empty set is always flushed, by definition.
   @override
   bool get isFlushed => true;
 
   /// Nothing happens when you flush a empty set, by definition.
   @override
   ISetEmpty<T> get flush => this;
 
+  /// An empty set is always empty, by definition
+  @override
+  bool get isEmpty => true;
+
+  /// An empty set is always empty, by definition
+  @override
+  bool get isNotEmpty => false;
+
   @override
   int get _counter => 0;
 

test/ilist/ilist_empty_test.dart

@@ -72,4 +72,9 @@ void main() {
     expect(const IList.empty().equalItemsAndConfig(const IList.empty()), isTrue);
     expect(const IList.empty().equalItemsAndConfig(const IListEmpty()), isTrue);
   });
+
+  test(".isEmpty() | .isNotEmpty()", () {
+    expect(const IList.empty().isEmpty, isTrue);
+    expect(const IList.empty().isNotEmpty, isFalse);
+  });
 }

test/imap/imap_empty_test.dart

@@ -81,4 +81,9 @@ void main() {
     expect(const IMap.empty().equalItemsAndConfig(const IMap.empty()), isTrue);
     expect(const IMap.empty().equalItemsAndConfig(const IMapEmpty()), isTrue);
   });
+
+  test(".isEmpty() | .isNotEmpty()", () {
+    expect(const IMap.empty().isEmpty, isTrue);
+    expect(const IMap.empty().isNotEmpty, isFalse);
+  });
 }

test/iset/iset_empty_test.dart

@@ -72,4 +72,9 @@ void main() {
     expect(const ISet.empty().equalItemsAndConfig(const ISet.empty()), isTrue);
     expect(const ISet.empty().equalItemsAndConfig(const ISetEmpty()), isTrue);
   });
+
+  test(".isEmpty() | .isNotEmpty()", () {
+    expect(const ISet.empty().isEmpty, isTrue);
+    expect(const ISet.empty().isNotEmpty, isFalse);
+  });
 }