chore: Corrects order of checks in data_source_federated_settings_identity_providers_test

[oarbusi]

Description

Change the order on which we check each IdP. The change in order is caused because now the API returns both SAML and OIDC in the same API call, instead of having to call the API 2 times (one for OIDC and one for SAML) and then appending the results.

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
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• This change requires a documentation update
• Documentation fix/enhancement

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Further comments

[AgustinBettati]

Curious why this did not fail with the original PR that changed the request behaviour

[lantoli]

i suppose it's not defined the API response order

[maastha]

Are we sure of this order? We should look into using TestCheckTypeSetElemAttr more for lists/sets.
An example where we use this already:
https://github.com/mongodb/terraform-provider-mongodbatlas/blob/master/internal/service/orginvitation/resource_org_invitation_test.go#L50

[lantoli]

similar to @maastha , how about having tests that don't depend on the order using TestCheckTypeSetElemNestedAttrs? I don't know if it's possible in this case,
e.g.: https://github.com/mongodb/terraform-provider-mongodbatlas/blob/master/internal/service/cluster/resource_cluster_test.go#L1339

[oarbusi]

Running the test now I consistently get this same order.
As per TestCheckTypeSetElemNestedAttrs and TestCheckTypeSetElemAttr I understand that this also checks a specific value has been set in at least one of the elements of the list/set. I don't like this for a couple of reasons:

• Checks the specific value. This increases the coupling between the test and the current state of testing environment resources, which could change. This happens because this resources does not have create operation through terraform yet. Once create operation is available I would agree that checking value can be useful and valuable.
• Majority of attributes being checked are only returned with a specific protocol(OIDC or SAML), so with these methods we could actually be missing edge cases where for some protocols the attributes are not being set when they should. But because it could be set in the other element of the list the check would be successful.

[maastha]

also, can we change the PR title to be more specific? as it shows up in the Changelog