Mocking data and Calling action from container - php

Question

I'm having issues making a Unit Testing because I have this code helperController Controller:
public static function applyDiscount(array $params, MoneyParser $moneyParser): Money
{
$discount = Money::BRL(0);
switch ($params['typeOf']) {
case 'above_value':
$amount = $params['value']->subtract($params['value']->multiply(0.85));
$discount = $discount->add($amount);
break;
case 'above_quantity':
$subtractedQuantity = intval(round($params['quantity'] / 3));
$value = $params['value']->multiply($subtractedQuantity);
$discount = $discount->add($value);
break;
case 'same_category':
$lowestVal = 0;
foreach ($params['cart'] as $item) {
if (empty($lowestVal)) {
$lowestVal = $item['unitPrice'];
} elseif ($item['unitPrice'] < $lowestVal) {
$lowestVal = $item['unitPrice'];
}
}
$valueOf = floatval($lowestVal) * 0.40;
$rounded = floor($valueOf * 100) / 100;
$unitPrice = $moneyParser->parse(strval($rounded), 'BRL');
$discount = $discount->add($unitPrice);
break;
case 'for_employees':
$amount = $params['value']->subtract($params['value']->multiply(0.80));
$discount = $discount->add($amount);
break;
case 'for_newones':
$amount = $moneyParser->parse('25', 'BRL');
$discount = $discount->add($amount);
break;
}
return $discount;
}
And I'm trying to mock the data to test it, for example, in the first case I'm trying to do this:
public function testApplyDiscountAboveValue(): void
{
$params = [
'typeOf' => 'above_value',
'value' => Money::BRL('3001'),
];
$money = app(MoneyParser::class);
$currency = app(Currency::class, ['code' => 'BRL']);
$moneyValue = app(Money::class, [
'amount' => 3001,
'currency' => $currency
]);
$discount = app(Money::class, [
'amount' => 450,
'currency' => $currency
]);
$mock = Mockery::mock($moneyValue);
$mock->shouldReceive('multiply')
->with(0.85)
->once()
->andReturn(Money::BRL('2550'));
$mock->shouldReceive('subtract')
->with(Money::BRL('2550'))
->once()
->andReturn(Money::BRL('450'));
$mock->shouldReceive('add')
->with(Money::BRL('450'))
->once()
->andReturn(Money::BRL('450'));
$response = app(HelperDiscountController::class)->applyDiscount($params, $money);
$this->assertEquals($discount, $response);
}
When I execute the phpunit my result is this:
App\Http\Controllers\HelperDiscountControllerTest::testApplyDiscountAboveValue
Mockery\Exception\InvalidCountException: Method multiply(0.85) from Mockery_0_Money_Money_Money_Money should be called
exactly 1 times but called 0 times.
I'm trying to understand what I am doing wrong. Did I have all the necessary adaptations to test my code at least for the first case?

Answer 1

First of all, if you have a static method in a controller, you are doing something wrong, it should be a non-static method, like this:
public function applyDiscount(array $params, MoneyParser $moneyParser): Money
{
// ...
}
Second, if the method applyDiscount is a helper method inside a controller or a parent controller, I would not pass an array $params, but directly a Request $request and use that object, because the array could have missing indexes and you should constantly validate them, with a Request object you can directly do $request->has('param') or do $request->input('param') (and pass a second parameter if you want a default value different from null if param is not present on the request as a parameter).
I do see that, for example, $params['value'] is an object, because you are doing operations on it, so if $params is not a parameter (you will never get an object from a Request as a parameter) then rename the variable to something else that truly repesent what it has, or at least, pass the content as separte method's parameters instead of an array of objects or similar.
Third, now onto the test. $response = app(HelperDiscountController::class)->applyDiscount($params, $money); will never work (get the mock), because you are never passing that mock into the Service Cointaner or into an instance as a dependency, you are creating the mock and not using it anywhere.
The code is a little bit confusing for me right now, but what you should have is something like this:
Controller
public function applyDiscount(Request $request, ): Money
{
// Validate or use a Form Request
// Do anything else you would need to
$result = $this->helperMethod(... needed params);
// Either return the result or process more stuff and return something if needed
return $result;
}
Test
public function testApplyDiscountAboveValue(): void
{
// When you need to mock something, you do it this way
$mock = $this->mock(WhateverClass::class);
$mock->shouldReceive('multiply')
->with(0.85)
->once()
->andReturn(Money::BRL('2550'));
$mock->shouldReceive('subtract')
->with(Money::BRL('2550'))
->once()
->andReturn(Money::BRL('450'));
$mock->shouldReceive('add')
->with(Money::BRL('450'))
->once()
->andReturn(Money::BRL('450'));
$response = $this->post(
'your/url/to/the/controller/endpoint',
[
'param1' => 'data1',
'paramN' => 'dataN',
],
);
$this->assertEquals($discount, $response);
}
See that:
When you use $this->mock(Class), it is internally binding that class resolution (when you do app(class) or resolve(class) or you let Laravel use Dependency Injection), it will return that mock
I am calling an endpoint using $this->post(url, data), you can use any HTTP method, but must match the route (that is how you test routes)
You need to share more info becausue it is very confusing (for me) what you are trying to test
Check my StackOverflow profile, I have some links in my profile about testing, it will help you a lot
Check the documentation as it is already explained in there most of the things you are trying to do
HTTP test
Mocking
Automatic Resolving/Dependency Injection