cdk snapshot testing with the ability to exclude or include assets

example.ts

import { SynthUtils } from '@aws-cdk/assert';
import * as cdk from 'aws-cdk-lib';
import { Stack, StageSynthesisOptions } from 'aws-cdk-lib';
import { Template } from 'aws-cdk-lib/assertions';
import { InfrastructureStack } from '../../src/lib/infrastructure-stack';

type Options = StageSynthesisOptions & {
    /**
     * Ignore Assets
     */
    ignoreAssets?: boolean;
    /**
     * Remove only resources of given types, e.g. subsetResourceTypes: ['AWS::SNS::Topic']
     */
    removeResourceTypes?: string[];
    /**
     * Remove only resources of given keys, e.g. subsetResourceKeys: ['TopicX']
     */
    removeResourceKeys?: string[];
    /**
     * Match only resources of given types, e.g. subsetResourceTypes: ['AWS::SNS::Topic']
     */
    subsetResourceTypes?: string[];
    /**
     * Match only resources of given keys, e.g. subsetResourceKeys: ['TopicX']
     */
    subsetResourceKeys?: string[];
    propertyMatchers?: { [property: string]: unknown };
};

const postProcessedStack = (stack: Stack, options: Options = {}) => {
    const { ignoreAssets = false, removeResourceTypes, removeResourceKeys, subsetResourceTypes, subsetResourceKeys, ...synthOptions } = options;

    const template = SynthUtils.toCloudFormation(stack, synthOptions);

    if (ignoreAssets && template.Resources) {
        if (template.Parameters) {
            template.Parameters = expect.any(Object);
        }

        // eslint-disable-next-line @typescript-eslint/no-explicit-any
        Object.values(template.Resources).forEach((resource: any) => {
            if (resource?.Properties?.Code) {
                resource.Properties.Code = expect.any(Object);
            }
        });
    }

    if (subsetResourceTypes && template.Resources) {
        for (const [key, resource] of Object.entries(template.Resources)) {
            // eslint-disable-next-line @typescript-eslint/no-explicit-any
            if (!subsetResourceTypes.includes((resource as any).Type)) {
                delete template.Resources[key];
            }
        }
    }

    if (subsetResourceKeys && template.Resources) {
        for (const [key] of Object.entries(template.Resources)) {
            if (!subsetResourceKeys.includes(key)) {
                delete template.Resources[key];
            }
        }
    }

    if (removeResourceTypes && template.Resources) {
        for (const [key, resource] of Object.entries(template.Resources)) {
            // eslint-disable-next-line @typescript-eslint/no-explicit-any
            if (removeResourceTypes.includes((resource as any).Type)) {
                delete template.Resources[key];
            }
        }
    }

    if (removeResourceKeys && template.Resources) {
        for (const [key] of Object.entries(template.Resources)) {
            if (removeResourceKeys.includes(key)) {
                delete template.Resources[key];
            }
        }
    }

    return Template.fromJSON(template);
};

describe('CDK Infra tests - master', () => {
    const app = new cdk.App();
    const templateMaster = postProcessedStack(
        new InfrastructureStack(app, 'some, 'stack', valueObject, {
            env: {
                account: something,
                region: something,
            },
        }),
        { ignoreAssets: true, removeResourceTypes: ['AWS::CloudFormation::Stack', 'Custom::AWSCDKOpenIdConnectProvider'] }, // removes assets for nested stacks e.d. as well
    );

    test('CDK_SNAPSHOT - Matches the snapshot', () => {
        expect(templateMaster).toMatchSnapshot();
    });

...