When using the function dagster.materialize_to_memory in testing, I want to provide mock data for some of the upstream assets. How can I provide a resousource that has the key_prefix "silver" and the name "bar"?

To provide mock data for upstream assets when using

dagster.materialize_to_memory

in testing, you can create mock asset definitions that return the values you want to use in your test. However, the documentation does not provide a direct example of how to provide a resource with a specific

key_prefix

and

name

using

materialize_to_memory

. The general approach to testing with mock data involves creating mock asset definitions and then using

materialize_to_memory

to materialize the assets with the mock data. Here's a simplified example based on the documentation:

python
from dagster import asset, materialize_to_memory

@asset
def mock_upstream_asset():
    # Return the mock data you want to use for your test
    return mock_data

# Replace 'your_asset' with the actual asset that depends on the upstream asset
@asset
def your_asset(mock_upstream_asset):
    # Your asset logic here
    ...

# Use materialize_to_memory to materialize your asset with the mock data
def test_your_asset():
    result = materialize_to_memory([your_asset, mock_upstream_asset])
    assert result.success
    # Additional assertions can be made here

In this example,

mock_upstream_asset

is a mock asset that you define to return the mock data you want to use in your test. You then include both the mock asset and the asset under test in the call to

materialize_to_memory

. If you need to specify a

key_prefix

for the mock asset, you can do so using the

key_prefix

parameter in the

@asset

decorator. However, the documentation does not provide an explicit example of how to use

key_prefix

in conjunction with

materialize_to_memory

. If you need to mock an asset with a specific

key_prefix

and

name

, you would typically define the mock asset with those parameters and then use it in your test as shown above. For more complex scenarios or if you need to provide a resource with a specific

key_prefix

and

name

, you may need to look for additional documentation or examples, or consider reaching out to the Dagster community for guidance. Testing | Dagster button Add an

asset_values

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