atk4\data\tests\BusinessModelTest::testExampleFromDoc PHP Method

    public function testExampleFromDoc()
    {
        $m = new Model_User();
        $m->addField('salary', ['default' => 1000]);
        $this->assertEquals(false, isset($m['salary']));
        // false
        $this->assertEquals(1000, $m['salary']);
        // 1000
        // Next we load record from $db
        $m->data = ['salary' => 2000];
        $this->assertEquals(2000, $m['salary']);
        // 2000 (from db)
        $this->assertEquals(false, isset($m['salary']));
        // false, was not changed
        $m['salary'] = 3000;
        $this->assertEquals(3000, $m['salary']);
        // 3000 (changed)
        $this->assertEquals(true, isset($m['salary']));
        // true
        unset($m['salary']);
        // return to original value
        $this->assertEquals(2000, $m['salary']);
        // 2000
        $this->assertEquals(false, isset($m['salary']));
        // false
    }