Inherit @ava/babel-preset-transform-test-files implementation

README.md

@@ -2,9 +2,9 @@
 
 Translations: [Français](https://github.com/avajs/ava-docs/tree/master/fr_FR/related/babel/README.md)
 
-Adds [Babel 7](https://babeljs.io) support to [AVA](https://avajs.dev) so you can use the latest JavaScript syntax in your tests. We do this by compiling test and helper files using our `@ava/babel/stage-4` preset. We also use a [second preset, `@ava/transform-test-files`](https://github.com/avajs/babel-preset-transform-test-files) to enable [enhanced assertion messages](https://github.com/avajs/ava/blob/master/docs/03-assertions.md#enhanced-assertion-messages) and detect improper use of `t.throws()` assertions.
+Adds [Babel 7](https://babeljs.io) support to [AVA](https://avajs.dev) so you can use the latest JavaScript syntax in your tests. We do this by compiling test and helper files using our `@ava/babel/stage-4` preset. We also use a second preset, `@ava/babel/transform-test-files` to enable [enhanced assertion messages](https://github.com/avajs/ava/blob/master/docs/03-assertions.md#enhanced-assertion-messages) and detect improper use of `t.throws()` assertions.
 
-By default our Babel pipeline is applied to test and helper files ending in `.cjs` and `.js`. If your project uses Babel then we'll automatically compile these files using your project's Babel configuration. The `@ava/transform-helper-files` preset is applied first, and the `@ava/babel/stage-4` last.
+By default our Babel pipeline is applied to test and helper files ending in `.cjs` and `.js`. If your project uses Babel then we'll automatically compile these files using your project's Babel configuration. The `@ava/babel/transform-helper-files` preset is applied first, and the `@ava/babel/stage-4` last.
 
 If you are using Babel for your source files then you must also [configure source compilation](#compile-sources).
 

espower-patterns.json

@@ -0,0 +1,3 @@
+[
+	"t.assert(value, [message])"
+]

index.js

@@ -163,7 +163,7 @@ function createCompileFn({babelOptions, cacheDir, compileEnhancements, projectDi
 
 	const ensureStage4 = wantsStage4(babelOptions, projectDir);
 	const containsStage4 = makeValueChecker('./stage-4');
-	const containsTransformTestFiles = makeValueChecker('@ava/babel-preset-transform-test-files');
+	const containsTransformTestFiles = makeValueChecker('./transform-test-files');
 
 	const loadOptions = filename => {
 		const partialConfig = babel.loadPartialConfig({
@@ -193,7 +193,7 @@ function createCompileFn({babelOptions, cacheDir, compileEnhancements, projectDi
 
 		if (compileEnhancements && !partialOptions.presets.some(containsTransformTestFiles)) {
 			// Apply first.
-			partialOptions.presets.push(createConfigItem('@ava/babel-preset-transform-test-files', 'preset', {powerAssert: true}));
+			partialOptions.presets.push(createConfigItem('./transform-test-files', 'preset', {powerAssert: true}));
 		}
 
 		const hash = hashPartialConfig(partialConfig, projectDir, pluginAndPresetHashes);

package.json

@@ -6,8 +6,10 @@
     "node": ">=10.18.0 <11 || >=12.14.0 <13 || >=13.5.0"
   },
   "files": [
+    "espower-patterns.json",
     "index.js",
     "stage-4.js",
+    "transform-test-files.js",
     "throws-helper.js",
     "stage-4-plugins"
   ],
@@ -22,14 +24,14 @@
     "test": "xo && nyc ava"
   },
   "dependencies": {
-    "@ava/babel-preset-transform-test-files": "^6.0.0",
     "@babel/core": "^7.7.7",
     "@babel/generator": "^7.7.7",
     "@babel/plugin-proposal-async-generator-functions": "^7.7.4",
     "@babel/plugin-proposal-dynamic-import": "^7.7.4",
     "@babel/plugin-proposal-optional-catch-binding": "^7.7.4",
     "@babel/plugin-transform-dotall-regex": "^7.7.7",
     "@babel/plugin-transform-modules-commonjs": "^7.7.5",
+    "babel-plugin-espower": "^3.0.1",
     "concordance": "^4.0.0",
     "convert-source-map": "^1.7.0",
     "dot-prop": "^5.2.0",

test/transform-test-files.js

@@ -0,0 +1,58 @@
+const {runInNewContext} = require('vm');
+const test = require('ava');
+const babel = require('@babel/core');
+const empower = require('empower-core');
+const throwsHelper = require('../throws-helper');
+const buildPreset = require('../transform-test-files');
+
+const ESPOWER_PATTERNS = require('../espower-patterns.json');
+
+test('throws-helper is included', t => {
+	const {plugins} = buildPreset(babel);
+	t.true(plugins.includes(throwsHelper));
+});
+
+test('resulting preset transforms assertion patterns', t => {
+	const {code} = babel.transform(`
+		const value = 'value'
+
+		// "Execute" the patterns. Hardcode them here, otherwise it's cheating.
+		t.assert(value)
+	`, {
+		ast: false,
+		babelrc: false,
+		filename: __filename,
+		presets: [buildPreset]
+	});
+
+	const appliedPatterns = [];
+	// Create a stub assertion object that can be enhanced using empower-core
+	const assert = ESPOWER_PATTERNS
+		.map(p => /^t\.(.+)\(/.exec(p)[1]) // eslint-disable-line prefer-named-capture-group
+		.reduce((assert, name) => {
+			assert[name] = () => {};
+			return assert;
+		}, {});
+
+	runInNewContext(code, {
+		t: empower(assert, {
+			onSuccess({matcherSpec: {pattern}, powerAssertContext}) {
+				if (powerAssertContext) { // Only available if the empower plugin transformed the assertion
+					appliedPatterns.push(pattern);
+				}
+			},
+			patterns: ESPOWER_PATTERNS
+		})
+	});
+	t.deepEqual(appliedPatterns, ESPOWER_PATTERNS);
+});
+
+test('the espower plugin can be disabled', t => {
+	const expected = 't.assert(value);';
+	const {code} = babel.transform(expected, {
+		ast: false,
+		babelrc: false,
+		presets: [[require.resolve('../transform-test-files'), {powerAssert: false}]]
+	});
+	t.is(code, expected);
+});

transform-test-files.js

@@ -0,0 +1,17 @@
+'use strict';
+const ESPOWER_PATTERNS = require('./espower-patterns.json');
+
+module.exports = (context, options) => {
+	const plugins = [];
+
+	if (!options || options.powerAssert !== false) {
+		plugins.push([require('babel-plugin-espower'), {
+			embedAst: true,
+			patterns: ESPOWER_PATTERNS
+		}]);
+	}
+
+	plugins.push(require('./throws-helper'));
+
+	return {plugins};
+};