Magic assert (#1154)

Author: Vadim Demedes

lib/assert.js

@@ -17,15 +17,17 @@ function create(val, expected, operator, msg, fn) {
 	return {
 		actual: val,
 		expected,
-		message: msg,
+		message: msg || ' ',
 		operator,
 		stackStartFunction: fn
 	};
 }
 
 function test(ok, opts) {
 	if (!ok) {
-		throw new assert.AssertionError(opts);
+		const err = new assert.AssertionError(opts);
+		err.showOutput = ['fail', 'throws', 'notThrows'].indexOf(err.operator) === -1;
+		throw err;
 	}
 }
 
@@ -109,7 +111,7 @@ x.throws = (fn, err, msg) => {
 
 		return result;
 	} catch (err) {
-		test(false, create(err.actual, err.expected, err.operator, err.message, x.throws));
+		test(false, create(err.actual, err.expected, 'throws', err.message, x.throws));
 	}
 };
 
@@ -134,7 +136,7 @@ x.notThrows = (fn, msg) => {
 	try {
 		assert.doesNotThrow(fn, msg);
 	} catch (err) {
-		test(false, create(err.actual, err.expected, err.operator, err.message, x.notThrows));
+		test(false, create(err.actual, err.expected, 'notThrows', err.message, x.notThrows));
 	}
 };
 
@@ -163,21 +165,33 @@ x._snapshot = function (tree, optionalMessage, match, snapshotStateGetter) {
 		snapshotState: state
 	};
 
-	const result = toMatchSnapshot.call(context, tree);
+	// symbols can't be serialized and saved in a snapshot,
+	// that's why tree is saved in `jsx` prop, so that JSX can be detected later
+	const serializedTree = tree.$$typeof === Symbol.for('react.test.json') ? {__ava_react_jsx: tree} : tree; // eslint-disable-line camelcase
+	const result = toMatchSnapshot.call(context, JSON.stringify(serializedTree));
 
-	let message = 'Please check your code or --update-snapshots\n\n';
+	let message = 'Please check your code or --update-snapshots';
 
 	if (optionalMessage) {
-		message += indentString(optionalMessage, 2);
-	}
-
-	if (typeof result.message === 'function') {
-		message += indentString(result.message(), 2);
+		message += '\n\n' + indentString(optionalMessage, 2);
 	}
 
 	state.save();
 
-	test(result.pass, create(result, false, 'snapshot', message, x.snap));
+	let expected;
+
+	if (result.expected) {
+		// JSON in a snapshot is surrounded with `"`, because jest-snapshot
+		// serializes snapshot values too, so it ends up double JSON encoded
+		expected = JSON.parse(result.expected.slice(1).slice(0, -1));
+		// Define a `$$typeof` symbol, so that pretty-format detects it as React tree
+		if (expected.__ava_react_jsx) { // eslint-disable-line camelcase
+			expected = expected.__ava_react_jsx; // eslint-disable-line camelcase
+			Object.defineProperty(expected, '$$typeof', {value: Symbol.for('react.test.json')});
+		}
+	}
+
+	test(result.pass, create(tree, expected, 'snapshot', message, x.snapshot));
 };
 
 x.snapshot = function (tree, optionalMessage) {

lib/cli.js

@@ -129,9 +129,9 @@ exports.run = () => {
 	if (cli.flags.tap && !cli.flags.watch) {
 		reporter = tapReporter();
 	} else if (cli.flags.verbose || isCi) {
-		reporter = verboseReporter();
+		reporter = verboseReporter({basePath: pkgDir});
 	} else {
-		reporter = miniReporter({watching: cli.flags.watch});
+		reporter = miniReporter({watching: cli.flags.watch, basePath: pkgDir});
 	}
 
 	reporter.api = api;

lib/code-excerpt.js

@@ -0,0 +1,45 @@
+'use strict';
+const fs = require('fs');
+const equalLength = require('equal-length');
+const codeExcerpt = require('code-excerpt');
+const truncate = require('cli-truncate');
+const chalk = require('chalk');
+
+const formatLineNumber = (lineNumber, maxLineNumber) => {
+	return ' '.repeat(String(maxLineNumber).length - String(lineNumber).length) + lineNumber;
+};
+
+module.exports = (file, line, options) => {
+	options = options || {};
+
+	const maxWidth = options.maxWidth || 80;
+	const source = fs.readFileSync(file, 'utf8');
+	const excerpt = codeExcerpt(source, line, {around: 1});
+	if (!excerpt) {
+		return null;
+	}
+
+	const lines = excerpt.map(item => ({
+		line: item.line,
+		value: truncate(item.value, maxWidth - String(line).length - 5)
+	}));
+
+	const joinedLines = lines.map(line => line.value).join('\n');
+	const extendedLines = equalLength(joinedLines).split('\n');
+
+	return lines
+		.map((item, index) => ({
+			line: item.line,
+			value: extendedLines[index]
+		}))
+		.map(item => {
+			const isErrorSource = item.line === line;
+
+			const lineNumber = formatLineNumber(item.line, line) + ':';
+			const coloredLineNumber = isErrorSource ? lineNumber : chalk.grey(lineNumber);
+			const result = ` ${coloredLineNumber} ${item.value}`;
+
+			return isErrorSource ? chalk.bgRed(result) : result;
+		})
+		.join('\n');
+};

lib/colors.js

@@ -2,12 +2,13 @@
 const chalk = require('chalk');
 
 module.exports = {
-	title: chalk.white,
+	title: chalk.bold.white,
 	error: chalk.red,
 	skip: chalk.yellow,
 	todo: chalk.blue,
 	pass: chalk.green,
 	duration: chalk.gray.dim,
+	errorSource: chalk.gray,
 	errorStack: chalk.gray,
 	stack: chalk.red,
 	information: chalk.magenta

lib/enhance-assert.js

@@ -1,67 +1,79 @@
 'use strict';
-
-module.exports = enhanceAssert;
-module.exports.formatter = formatter;
+const dotProp = require('dot-prop');
 
 // When adding patterns, don't forget to add to
 // https://github.com/avajs/babel-preset-transform-test-files/blob/master/espower-patterns.json
 // Then release a new version of that preset and bump the SemVer range here.
-module.exports.PATTERNS = [
+const PATTERNS = [
 	't.truthy(value, [message])',
 	't.falsy(value, [message])',
 	't.true(value, [message])',
 	't.false(value, [message])',
 	't.is(value, expected, [message])',
 	't.not(value, expected, [message])',
-	't.deepEqual(value, expected, [message])',
-	't.notDeepEqual(value, expected, [message])',
 	't.regex(contents, regex, [message])',
 	't.notRegex(contents, regex, [message])'
 ];
 
-module.exports.NON_ENHANCED_PATTERNS = [
+const NON_ENHANCED_PATTERNS = [
 	't.pass([message])',
 	't.fail([message])',
 	't.throws(fn, [message])',
 	't.notThrows(fn, [message])',
 	't.ifError(error, [message])',
-	't.snapshot(contents, [message])'
+	't.snapshot(contents, [message])',
+	't.is(value, expected, [message])',
+	't.not(value, expected, [message])',
+	't.deepEqual(value, expected, [message])',
+	't.notDeepEqual(value, expected, [message])'
 ];
 
-function enhanceAssert(opts) {
+const enhanceAssert = opts => {
 	const empower = require('empower-core');
-
-	const enhanced = empower(
-		opts.assert,
-		{
-			destructive: false,
-			onError: opts.onError,
-			onSuccess: opts.onSuccess,
-			patterns: module.exports.PATTERNS,
-			wrapOnlyPatterns: module.exports.NON_ENHANCED_PATTERNS,
-			bindReceiver: false
-		}
-	);
+	const enhanced = empower(opts.assert, {
+		destructive: false,
+		onError: opts.onError,
+		onSuccess: opts.onSuccess,
+		patterns: PATTERNS,
+		wrapOnlyPatterns: NON_ENHANCED_PATTERNS,
+		bindReceiver: false
+	});
 
 	return enhanced;
-}
+};
 
-function formatter() {
-	const createFormatter = require('power-assert-context-formatter');
-	const SuccinctRenderer = require('power-assert-renderer-succinct');
-	const AssertionRenderer = require('power-assert-renderer-assertion');
+const isRangeMatch = (a, b) => {
+	return (a[0] === b[0] && a[1] === b[1]) ||
+		(a[0] > b[0] && a[0] < b[1]) ||
+		(a[1] > b[0] && a[1] < b[1]);
+};
 
-	return createFormatter({
-		renderers: [
-			{
-				ctor: AssertionRenderer
-			},
-			{
-				ctor: SuccinctRenderer,
-				options: {
-					maxDepth: 3
-				}
-			}
-		]
-	});
-}
+const computeStatement = (tokens, range) => {
+	return tokens
+		.filter(token => isRangeMatch(token.range, range))
+		.map(token => token.value === undefined ? token.type.label : token.value)
+		.join('');
+};
+
+const getNode = (ast, path) => dotProp.get(ast, path.replace(/\//g, '.'));
+
+const formatter = () => {
+	return context => {
+		const ast = JSON.parse(context.source.ast);
+		const tokens = JSON.parse(context.source.tokens);
+		const args = context.args[0].events;
+
+		return args
+			.map(arg => {
+				const range = getNode(ast, arg.espath).range;
+
+				return [computeStatement(tokens, range), arg.value];
+			})
+			.reverse();
+	};
+};
+
+module.exports = enhanceAssert;
+module.exports.PATTERNS = PATTERNS;
+module.exports.NON_ENHANCED_PATTERNS = NON_ENHANCED_PATTERNS;
+module.exports.formatter = formatter;

lib/extract-stack.js

@@ -0,0 +1,10 @@
+'use strict';
+const stackLineRegex = /^.+ \(.+:[0-9]+:[0-9]+\)$/;
+
+module.exports = stack => {
+	return stack
+		.split('\n')
+		.filter(line => stackLineRegex.test(line))
+		.map(line => line.trim())
+		.join('\n');
+};

lib/format-assert-error.js

@@ -0,0 +1,72 @@
+'use strict';
+const indentString = require('indent-string');
+const chalk = require('chalk');
+const diff = require('diff');
+
+const cleanUp = line => {
+	if (line[0] === '+') {
+		return `${chalk.green('+')} ${line.slice(1)}`;
+	}
+
+	if (line[0] === '-') {
+		return `${chalk.red('-')} ${line.slice(1)}`;
+	}
+
+	if (line.match(/@@/)) {
+		return null;
+	}
+
+	if (line.match(/\\ No newline/)) {
+		return null;
+	}
+
+	return ` ${line}`;
+};
+
+module.exports = err => {
+	if (err.statements) {
+		const statements = JSON.parse(err.statements);
+
+		return statements
+			.map(statement => `${statement[0]}\n${chalk.grey('=>')} ${statement[1]}`)
+			.join('\n\n') + '\n';
+	}
+
+	if ((err.actualType === 'object' || err.actualType === 'array') && err.actualType === err.expectedType) {
+		const patch = diff.createPatch('string', err.actual, err.expected);
+		const msg = patch
+			.split('\n')
+			.slice(4)
+			.map(cleanUp)
+			.filter(Boolean)
+			.join('\n');
+
+		return `Difference:\n\n${msg}`;
+	}
+
+	if (err.actualType === 'string' && err.expectedType === 'string') {
+		const patch = diff.diffChars(err.actual, err.expected);
+		const msg = patch
+			.map(part => {
+				if (part.added) {
+					return chalk.bgGreen.black(part.value);
+				}
+
+				if (part.removed) {
+					return chalk.bgRed.black(part.value);
+				}
+
+				return part.value;
+			})
+			.join('');
+
+		return `Difference:\n\n${msg}\n`;
+	}
+
+	return [
+		'Actual:\n',
+		`${indentString(err.actual, 2)}\n`,
+		'Expected:\n',
+		`${indentString(err.expected, 2)}\n`
+	].join('\n');
+};