[Bug] system tests cannot use associative arrays as query parameter values

[diosmosis]

What happened?

This is an issue that affects plugin development, specifically writing system tests for API methods.

System tests construct test URLs and use them to invoke API methods. When using an associative array, eg:

['apiParameters' => ['param1' => 1, 'param2' => 2]]

for the 'otherRequestParameters' property of an API test configuration, it is transformed to this in the test URL:

apiParameters[]=1&apiParameters[]=2

This makes it impossible to test API.getMetadata/API.getProcessedReport with a custom apiParameters value.

What should happen?

Using apiParameters in the otherRequestParameters property should be correctly converted to a URL that respects associative array keys, like this:

apiParameters[param1]=1&apiParameters[param2]=2

How can this be reproduced?

This issue can be reproduced with the following code (based on SystemTestCase::runApiTests()):

$api = 'API.getMetadata';
$params = [
    'idSite' => $idSite,
    'date' => $date,
    'periods'    => ['day'],
    'apiModule'  => 'Goals',
    'apiAction'  => 'getItemsCategory',
    'otherRequestParameters' => [
        'apiParameters' => ['idGoal' => 5],
    ]
];

$testConfig = new ApiTestConfig($params);
$testRequests = new Collection($api, $testConfig, $api);

foreach ($testRequests->getRequestUrls() as $apiId => $requestUrl) {
    Assert::assertStringNotContainsString('apiParameters[]=', $requestUrl);
    Assert::assertStringContainsString('apiParameters[idGoal]=', $requestUrl);
}

Matomo version

5.3.0

PHP version

No response

Server operating system

No response

What browsers are you seeing the problem on?

No response

Computer operating system

No response

Relevant log output

Validations

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• The provided steps to reproduce is a minimal reproducible of the Bug.