Fix issue with Set proper subset.

Author: markrogoyski

src/SetTheory/Set.php

@@ -37,7 +37,7 @@
  * $set = new Set([$array1, $array2]);
  *
  * The set will have only one element, because the arrays are equal.
- * $array2 === $array2 evaluates to true.
+ * $array1 === $array2 evaluates to true.
  *
  * Example (different objects):
  * $object1 = new \StdClass();
@@ -333,7 +333,7 @@ public function isProperSubset(Set $B): bool
         $A∩B = \array_intersect_key($this->A, $B_array);
         $A∖B = \array_diff_key($this->A, $B_array);
 
-        return (\count($A∩B) === \count($this->A)) && (empty($A∖B)) && (\count($this->A) === \count($B));
+        return (\count($A∩B) === \count($this->A)) && (empty($A∖B)) && ($this != $B);
     }
 
     /**
@@ -358,7 +358,7 @@ public function isSuperset(Set $B): bool
     /**
      * Superset (A ⊇ B & A ≠ B)
      * Is the set a superset of the other set?
-     * In other words, does the the set contain all the elements of the other set,
+     * In other words, does the set contain all the elements of the other set,
      * and the set is not the same set as the other set?
      *
      * @param  Set $B
@@ -469,10 +469,10 @@ public function symmetricDifference(Set $B): Set
     {
         $B_array = $B->asArray();
 
-        $A∪B = \array_intersect_key($this->A, $B_array);
+        $A∩B = \array_intersect_key($this->A, $B_array);
 
-        $A∖B = \array_diff_key($this->A, $A∪B);
-        $B∖A = \array_diff_key($B_array, $A∪B);
+        $A∖B = \array_diff_key($this->A, $A∩B);
+        $B∖A = \array_diff_key($B_array, $A∩B);
 
         return new Set($A∖B + $B∖A);
     }

tests/SetTheory/SetOperationsTest.php

@@ -958,7 +958,7 @@ public function dataProviderForIsNotSubset(): array
 
     /**
      * @test
-     * @dataProvider dataProviderForIsProperSet
+     * @dataProvider dataProviderForIsProperSubset
      */
     public function testIsProperSubset(array $A, array $B)
     {
@@ -970,21 +970,121 @@ public function testIsProperSubset(array $A, array $B)
         $this->assertTrue($setA->isProperSubset($setB));
     }
 
+    public function dataProviderForIsProperSubset(): array
+    {
+        return [
+            [
+                [],
+                [1],
+            ],
+            [
+                [1],
+                [1, 2],
+            ],
+            [
+                [1, 2],
+                [1, 2, 3],
+            ],
+            [
+                [1, 3, 2],
+                [1, 2, 3, 4],
+            ],
+            [
+                [1, 2,'a', 4.5, new Set([1, 2])],
+                [1, 2, 3, 'a', 4.5, new Set([1, 2])],
+            ],
+            [
+                [1, 3, 'a', 4.5, new Set([1, 2])],
+                [1, 2, 3, 'a', 4.5, new Set([1, 2])],
+            ],
+            [
+                [1, 2, 3, 'a', 4.5, new Set([1, 2]), -1, -2, 3.5],
+                [1, 2, 3, 'a', 4.5, new Set([1, 2]), -1, -2, 2.4, 3.5],
+            ],
+        ];
+    }
+
+
+    /**
+     * @test
+     * @dataProvider dataProviderForIsSameSets
+     * @dataProvider dataProviderForIsProperSuperset
+     */
+    public function testIsNotProperSubset(array $A, array $B)
+    {
+        // Given
+        $setA = new Set($A);
+        $setB = new Set($B);
+
+        // Then
+        $this->assertFalse($setA->isProperSubset($setB));
+    }
+
     /**
      * @test
-     * @dataProvider dataProviderForIsProperSet
+     * @dataProvider dataProviderForIsProperSuperset
      */
     public function testIsProperSuperset(array $A, array $B)
     {
         // Given
-        $setA = new Set($B);
-        $setB = new Set($A);
+        $setA = new Set($A);
+        $setB = new Set($B);
+
+        // Then
+        $this->assertTrue($setA->isProperSuperset($setB));
+    }
+
+    public function dataProviderForIsProperSuperset(): array
+    {
+        return [
+            [
+                [1],
+                [],
+            ],
+            [
+                [1, 2],
+                [1],
+            ],
+            [
+                [1, 2, 3],
+                [1, 2],
+            ],
+            [
+                [1, 2, 3, 4],
+                [1, 3, 2],
+            ],
+            [
+                [1, 2, 3, 'a', 4.5, new Set([1, 2])],
+                [1, 2,'a', 4.5, new Set([1, 2])],
+            ],
+            [
+                [1, 2, 3, 'a', 4.5, new Set([1, 2])],
+                [1, 3, 'a', 4.5, new Set([1, 2])],
+            ],
+            [
+                [1, 2, 3, 'a', 4.5, new Set([1, 2]), -1, -2, 2.4, 3.5],
+                [1, 2, 3, 'a', 4.5, new Set([1, 2]), -1, -2, 3.5],
+            ],
+        ];
+    }
+
+
+    /**
+     * @test
+     * @dataProvider dataProviderForIsSameSets
+     * @dataProvider dataProviderForIsProperSubset
+     */
+    public function testIsNotProperSuperset(array $A, array $B)
+    {
+        // Given
+        $setA = new Set($A);
+        $setB = new Set($B);
 
         // Then
         $this->assertFalse($setA->isProperSuperset($setB));
     }
 
-    public function dataProviderForIsProperSet(): array
+    public function dataProviderForIsSameSets(): array
     {
         return [
             [