docs(contributors): describe "npm package" tests (#3141)

Improve the README of the related test applications and add cross-links
in the documentation.

docs/contributors/supported-typescript-version.md

@@ -25,5 +25,6 @@ The README file mentions the oldest supported version of TypeScript. Update the
 
 Update the `typesVersions` attribute in the `package.json` file. This attribute is central.
 
-Run the automatic tests from the `test/typescript-support` directory: `npm test`. They should fail as they are currently using a too old TypeScript version.
+Run the automatic tests from the `test/typescript-support` directory (see the [typescript-support README](../../test/typescript-support/README.md)). They should fail as they are currently using a too old TypeScript version.
+
 Update the TypeScript version in the `package.json` file and run the tests again. They should now succeed.

docs/contributors/testing.md

@@ -211,6 +211,13 @@ Preview is available in the browser, simply open file `/bpmn-visu-js/test/perfor
 They ensure that the bundles provided in the npm package are working, and they are defined under `/test/bundles/`.
 
 
+### Npm package tests
+
+These tests are validating the usage of the npm package in TypeScript applications:
+- [typescript-support](../../test/typescript-support): validate the [minimal TypeScript version](./supported-typescript-version.md) supported by the library
+- [typescript-moduleResolution-bundler](../../test/typescript-moduleResolution-bundler): validate that the library can be used with the `bundler` module resolution strategy 
+
+
 ## Running tests 
 
 See `package.json` for extra available scripts

test/typescript-moduleResolution-bundler/README.md

@@ -2,7 +2,15 @@
 
 Relates to [missing types configuration in the package.json "exports" field](https://github.com/process-analytics/bpmn-visualization-js/pull/2972).
 
+## Setup
+
+The `bpmn-visualization` npm package must be built first. From the repository root, run:
+- `npm install`
+- `npm pack`
+
+
 ## Run
 
+From the folder of this test project, run:
 - `npm install`
 - `npm test`

test/typescript-support/README.md

@@ -0,0 +1,14 @@
+# Validate the minimal TypeScript version supported by bpmn-visualization
+
+## Setup
+
+The `bpmn-visualization` npm package must be built first. From the repository root, run:
+- `npm install`
+- `npm pack`
+
+
+## Run
+
+From the folder of this test project, run:
+- `npm install`
+- `npm test`