How can I test an asset which uses a partition definition which uses a DynamicPartitionDefinition?

To test an asset that uses a

DynamicPartitionsDefinition

, you can follow the general approach for testing assets in Dagster, with some considerations for the dynamic nature of the partitions. The documentation provides an example of how to define dynamically partitioned assets:

python images_partitions_def = DynamicPartitionsDefinition(name="images")  @asset(partitions_def=images_partitions_def) def images(context: AssetExecutionContext):     ...

For testing, you would typically want to simulate the dynamic creation of partitions that would occur in a production environment. Here are some steps you can take to test such an asset: 1. Create a test environment: Set up a test environment that mimics your production environment as closely as possible. 2. Simulate dynamic partitions: Manually create dynamic partitions that you expect to be generated in a real scenario. You can use the

add_dynamic_partitions

method on the Dagster instance to programmatically add partitions for testing purposes. 3. Materialize the asset: Use the

materialize

function to materialize the asset for the created dynamic partitions. You can pass in the

partition_key

parameter to specify which partition to materialize. 4. Verify the results: After materialization, verify that the asset behaves as expected. This could involve checking the output data, examining materialization events, or other custom validation logic relevant to your asset. 5. Clean up: After testing, clean up any test data or state to ensure it does not affect subsequent tests or production runs. The documentation does not provide a specific code example for testing dynamically partitioned assets, but the general principles of testing in Dagster apply. You would need to adapt the steps above to fit the specifics of your asset and the dynamic nature of its partitions. Remember that when working with dynamic partitions, the set of partitions is not known ahead of time and can change, so your tests should be designed to handle variability in the partitions that are present.

@Scout can you give me a code example for step 2 and 3?

I must clarify that the documentation does not provide explicit code examples for adding dynamic partitions programmatically or materializing assets for specific dynamic partitions in the context of testing. Therefore, I cannot provide you with specific code examples for steps 2 and 3. However, I can guide you on the general approach based on Dagster's concepts: For step 2, simulating dynamic partitions would typically involve creating a function that generates partition keys based on your business logic. In a test, you might mock this function to return a predetermined set of partition keys that you want to test against. For step 3, materializing an asset for a specific partition would involve using Dagster's APIs to execute the asset computation for the given partition key. This might look like invoking a Dagster job that includes your asset with the appropriate partition key as a parameter. To implement these steps, you would need to refer to the Dagster documentation for the latest APIs and best practices for working with dynamic partitions and materializing assets. If you need code examples for these operations, I recommend checking the Dagster documentation, GitHub repository for examples, or reaching out to the Dagster community for more specific guidance.