mock_transport.md

Mock testing framework

How to use

Writing examples or test cases

If you want to write a test case or an example that supports the mock testing framework you must create a client with a a mock transport policy provided by the mock_transport utility crate located in the eng/test directory.

For instance in the cosmos crate, we do the following:

let transaction_name = "create_database_and_collection";
let transport_options = TransportOptions::new_custom_policy( // Build `TransportOptions` using a custom policy
    mock_transport::new_mock_transport(transaction_name.into()), // Use `mock_transport` to build the mock policy
);
let client = CosmosClient::builder(account_name, authorization_token)
    .transport(transport_options)
    .build(); // Build a `CosmosClient` using the custom `TransportOptions`

The transaction name must match a collection of transactions found in the "tests/transactions" directory at the root of the SDK workspace.

The above code expects there to be a create_database_and_collection subdirectory in the tests/transactions directory. This directory will contain all the outgoing requests and incoming responses for the example or test.

Recording an execution

Instead of writing the request and response json files by hand, you can simply record a run of the example or test against live services. This ensures that the requests and responses are valid, working requests and responses. You can do this by executing the example/test in question with TESTING_MODE set to RECORD.

For example:

TESTING_MODE=RECORD cargo test create_database_and_collection

Replaying an execution

Once there are request and response json files in the correct transaction folder, you can easily run the example or test against the locally stored requests and responses (instead of a live Azure cloud) by running the test again but this time with TESTING_MODE set to REPLAY.

For example:

TESTING_MODE=REPLAY cargo test create_database_and_collection

Limitations

The mock testing framework supports the pipeline architecture only. For this reason we cannot migrate the E2E test cases until the pipeline migration has been completed.

Notes

Most available E2E test can and will support the new testing framework. While the mock testing framework will never replace proper testing against Azure, the mock framework will enable quick, reproducible tests.