Bicep Experimental Test Framework

Owner: Emily Redmond

Introduction

We began prototyping experimental test features early in summer 2023, and we’ve been encouraged by the level of customer interest in the project. While we are still early in exploring what the future of testing looks like in Bicep, we are eager to get early feedback. If you choose to enable the feature, beware the functionality is still experimental and subject to change at any time.

Read the full proposal for the testing framework here.

How to get started with experimental test framework

Enable assertions and testFramework experimental feature flags in a bicepconfig.json file. Both feature flags must be enabled for expected functionality.
Create a new .bicep file to author your tests, eg. tests.bicep. This must be a separate file from the .bicep template you want to test. Author a test block with the new test keyword, referencing a .bicep template you would like to test on the client-side (without deploying).
Author assert statements to validate parameters, variables, and resource names within the .bicep template file you would like to test that you referenced in your test blocks.
In your CLI, run the command bicep test <filepath_to_test_file> to run test blocks and their corresponding assert statements without deploying.

1. Enable experimental features

Enable testing experimental features in `bicepconfig.json`

Create bicepconfig.json file within your Bicep project repo

Within bicepconfig.json, define experimentalFeaturesEnabled and set testFramework: true and assertions: true

2. Test blocks

`test` block syntax:

test keyword
Name of test block (eg. testMain)
Reference to Bicep file to test (eg. ‘main.bicep’)
params object mocking parameter values from the Bicep file (eg. params: {env: 'prod'})

Example:

Lmitations:

You must pass in a parameter object, you cannot reference an existing parameter file currently
Test blocks must be in a separate file from the .bicep template you want to test
Test result output summary is not standardized

3. Assert statements

`assert` statement syntax:

assert keyword
Name of assert statement (eg. appName)
equals boolean validation expression (eg. = contains(appServiceApp.name, "${env}")

assert statements can be any boolean expression that references parameters, variables, or resource names. These boolean expressions can include Bicep functions such as "contains()", "length()", etc.

Examples:

Limitations:

You can only assert on parameters, variables, and resource names with current functionality
- You cannot assert on resource size, location, or other propreties yet as these depend on runtime deployment functionality