MathPHP\SetTheory\ImmutableSetTest::testActsLikeASet PHP Метод

    public function testActsLikeASet()
    {
        $A = new ImmutableSet([1, 2, 3]);
        $B = new ImmutableSet([3, 4, 5]);
        $this->assertEquals(3, $A->length());
        $this->assertEquals(3, $B->length());
        $this->assertFalse($A->isEmpty());
        $this->assertFalse($B->isEmpty());
        $this->assertTrue($A->isMember(1));
        $this->assertTrue($A->isMember(2));
        $this->assertTrue($A->isMember(3));
        $this->assertTrue($B->isMember(3));
        $this->assertTrue($B->isMember(4));
        $this->assertTrue($B->isMember(5));
        $this->assertTrue($A->isNotMember(10));
        $this->assertTrue($B->isNotMember(10));
        $this->assertFalse($A->isDisjoint($B));
        $this->assertFalse($A->isSubset($B));
        $this->assertFalse($A->isProperSubset($B));
        $this->assertFalse($A->isSuperset($B));
        $this->assertFalse($A->isProperSuperset($B));
        $this->assertEquals(new Set([1, 2, 3, 4, 5]), $A->union($B));
        $this->assertEquals(new Set([3]), $A->intersect($B));
        $this->assertEquals(new Set([1, 2]), $A->difference($B));
        $this->assertEquals(new Set([1, 2, 4, 5]), $A->symmetricDifference($B));
        $this->assertEquals(new Set([new Set([1, 3]), new Set([1, 4]), new Set([1, 5]), new Set([2, 3]), new Set([2, 4]), new Set([2, 5]), new Set([3, 3]), new Set([3, 4]), new Set([3, 5])]), $A->cartesianProduct($B));
        $this->assertEquals($A, $A->copy());
        $this->assertEquals('Set{1, 2, 3}', strval($A));
        $this->assertEquals(3, count($A));
        $this->assertEquals(3, count($B));
        $i = 0;
        foreach ($A as $x) {
            $i++;
        }
        $this->assertEquals(3, $i);
    }