chore: add readme for cloud-assembly-schema

packages/aws-cdk-lib/cloud-assembly-schema/README.md

@@ -0,0 +1,55 @@
+# Cloud Assembly Schema
+
+This module is part of the [AWS Cloud Development Kit](https://github.com/aws/aws-cdk) project.
+
+## Cloud Assembly
+
+The _Cloud Assembly_ is the output of the synthesis operation. It is produced as part of the
+[`cdk synth`](https://github.com/aws/aws-cdk/tree/main/packages/aws-cdk#cdk-synthesize)
+command, or the [`app.synth()`](https://github.com/aws/aws-cdk/blob/main/packages/@aws-cdk/core/lib/app.ts#L135) method invocation.
+
+Its essentially a set of files and directories, one of which is the `manifest.json` file. It defines the set of instructions that are
+needed in order to deploy the assembly directory.
+
+> For example, when `cdk deploy` is executed, the CLI reads this file and performs its instructions:
+>
+> - Build container images.
+> - Upload assets.
+> - Deploy CloudFormation templates.
+
+Therefore, the assembly is how the CDK class library and CDK CLI (or any other consumer) communicate. To ensure compatibility
+between the assembly and its consumers, we treat the manifest file as a well defined, versioned schema.
+
+## Schema
+
+This module contains the typescript structs that comprise the `manifest.json` file, as well as the
+generated [_json-schema_](./schema/cloud-assembly.schema.json).
+
+## Versioning
+
+The schema version is specified my the major version of the package release. It follows semantic versioning, but with a small twist.
+
+When we add instructions to the assembly, they are reflected in the manifest file and the _json-schema_ accordingly.
+Every such instruction, is crucial for ensuring the correct deployment behavior. This means that to properly deploy a cloud assembly,
+consumers must be aware of every such instruction modification.
+
+For this reason, every change to the schema, even though it might not strictly break validation of the _json-schema_ format,
+is considered `major` version bump. All changes that do not impact the schema are considered a `minor` version bump.
+
+## How to consume
+
+If you'd like to consume the [schema file](./schema/cloud-assembly.schema.json) in order to do validations on `manifest.json` files,
+simply download it from this repo and run it against standard _json-schema_ validators, such as [jsonschema](https://www.npmjs.com/package/jsonschema).
+
+Consumers must take into account the `major` version of the schema they are consuming. They should reject cloud assemblies
+with a `major` version that is higher than what they expect. While schema validation might pass on such assemblies, the deployment integrity
+cannot be guaranteed because some instructions will be ignored.
+
+> For example, if your consumer was built when the schema version was 2.0.0, you should reject deploying cloud assemblies with a
+> manifest version of 3.0.0.
+
+## Contributing
+
+The source code for this file has been moved to CDKLabs.
+
+See [Contribution Guide](https://github.com/cdklabs/cloud-assembly-schema/blob/main/CONTRIBUTING.md)

packages/aws-cdk-lib/jest.config.js

@@ -1 +1,18 @@
-"use strict";const baseConfig=require("@aws-cdk/cdk-build-tools/config/jest.config");module.exports={...baseConfig,testMatch:["<rootDir>/**/test/**/?(*.)+(test).ts"],coverageThreshold:{global:{branches:35,statements:55}}};
+const baseConfig = require('@aws-cdk/cdk-build-tools/config/jest.config');
+
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+module.exports = {
+  ...baseConfig,
+
+  // Different than usual
+  testMatch: [
+    '<rootDir>/**/test/**/?(*.)+(test).ts',
+  ],
+
+  coverageThreshold: {
+    global: {
+      branches: 35,
+      statements: 55,
+    },
+  },
+};