refactor: update COVERAGE.md to accommodate ava-nesm.config.js

Author: michaelfig

.github/workflows/test-all-packages.yml

@@ -148,7 +148,7 @@ jobs:
     # END-RESTORE-BOILERPLATE
 
     - name: generate coverage for all tests
-      run: yarn test:all-c8
+      run: 'yarn test:c8-all || :'
     - name: generate coverage/html reports
       run: yarn c8 report --reporter=html-spa --reports-dir=coverage/html --temp-directory=coverage/tmp
     - uses: actions/upload-artifact@v2

COVERAGE.md

@@ -3,7 +3,7 @@
 ## Caveat
 
 Until each module can be migrated to support Node.js's builtin ESM
-implementation (`NESM`), the coverage line numbers will be out-of-sync with
+implementation (`nesm`), the coverage line numbers will be out-of-sync with
 reality.
 
 In addition, we will have to implement source maps in all of our
@@ -12,7 +12,7 @@ source-to-source transforms (such as `@agoric/bundle-source`,
 
 ## Reports
 
-Coverage reports for the current main branch (whose packages support `NESM`) are
+Coverage reports for the current main branch (whose packages support `nesm`) are
 published by CI to: https://agoric-sdk-coverage.netlify.app
 
 You can create a report in any package (including the top-level directory):
@@ -27,34 +27,33 @@ yarn c8 report --reporter=html-spa
 open coverage/html/index.html
 ```
 
-## NESM Support
+## Node.js ESM Support
 
 With the current `patches/esm+3.2.25.diff`, it is possible to migrate packages
-to support both RESM (`-r esm`) and NESM.  If an `agoric-sdk` package has
-dependencies that support NESM, you can attempt to make it also support NESM by:
+to support both resm (`-r esm`) and nesm (Node.js ESM Support).  If an
+`agoric-sdk` package has dependencies that support nesm, you can attempt to make
+it also support nesm by:
 
-1. Make the following changes to its `package.json` (omitting comments):
+1. Create `ava-nesm.config.js` removing `"require": ["esm"]`:
+
+```sh
+../../scripts/ava-nesm.cjs > ava-nesm.config.js
+```
+
+2. Make the following changes to its `package.json` (omitting comments):
 
 ```json
 {
-  // Enable NESM support.
+  // Enable nesm support.
   "type": "module",
   "scripts": {
     // The following line enables coverage generation from the top.
-    "test:c8": "c8 $C8_OPTIONS ava",
-  },
-  "devDependencies": {
-    // Remove:
-    // "esm": "^3.2.25"
-  }
-  "ava": {
-    // Remove:
-    // "require": ["esm"]
+    "test:c8": "c8 $C8_OPTIONS ava --config=ava-nesm.config.js",
   }
 }
 ```
 
-2. Test that it runs correctly with both `yarn test` and `yarn test:c8`.
+3. Test that both `yarn test` and `yarn test:c8` run correctly.
 
 ## Planned Implementation
 

package.json

@@ -76,7 +76,7 @@
     "lint-check": "yarn workspaces run lint-check",
     "lint": "yarn workspaces run lint-check",
     "test": "ava",
-    "test:all-c8": "rm -rf coverage/tmp && C8_OPTIONS=\"--clean=false --temp-directory=$PWD/coverage/tmp\" lerna run test:c8 || :",
+    "test:c8-all": "rm -rf coverage/tmp && C8_OPTIONS=\"--clean=false --temp-directory=$PWD/coverage/tmp\" lerna run test:c8",
     "test:xs": "yarn workspaces run test:xs",
     "build": "yarn workspaces run build",
     "postinstall": "patch-package",

packages/swing-store-simple/ava-nesm.config.js

@@ -0,0 +1,6 @@
+export default {
+  "files": [
+    "test/**/test-*.js"
+  ],
+  "timeout": "2m"
+};

packages/swing-store-simple/package.json

@@ -13,7 +13,7 @@
   "scripts": {
     "build": "exit 0",
     "test": "ava",
-    "test:c8": "c8 $C8_OPTIONS ava",
+    "test:c8": "c8 $C8_OPTIONS ava --config=ava-nesm.config.js",
     "test:xs": "exit 0",
     "lint-fix": "eslint --fix '**/*.js'",
     "lint-check": "eslint '**/*.js'"
@@ -22,7 +22,8 @@
     "n-readlines": "^1.0.0"
   },
   "devDependencies": {
-    "ava": "^3.12.1"
+    "ava": "^3.12.1",
+    "esm": "^3.2.25"
   },
   "publishConfig": {
     "access": "public"
@@ -31,6 +32,9 @@
     "files": [
       "test/**/test-*.js"
     ],
+    "require": [
+      "esm"
+    ],
     "timeout": "2m"
   },
   "eslintConfig": {

scripts/ava-nesm.cjs

@@ -0,0 +1,16 @@
+#! /usr/bin/env node
+const fs = require('fs');
+const packageJson = fs.readFileSync('package.json', 'utf-8');
+const package = JSON.parse(packageJson);
+const { ava: avaConfig } = package;
+if (avaConfig.require) {
+  const newRequire = avaConfig.require.filter(m => m !== 'esm');
+  if (newRequire.length) {
+    avaConfig.require = newRequire;
+  } else {
+    delete avaConfig.require;
+  }
+}
+process.stdout.write(`\
+export default ${JSON.stringify(avaConfig, undefined, 2)};
+`);