/**
* @fileoverview Mocha test wrapper
* @author Ilya Volodin
*/
"use strict";
/* global describe, it */
/*
* This is a wrapper around mocha to allow for DRY unittests for eslint
* Format:
* RuleTester.run("{ruleName}", {
* valid: [
* "{code}",
* { code: "{code}", options: {options}, globals: {globals}, parser: "{parser}", settings: {settings} }
* ],
* invalid: [
* { code: "{code}", errors: {numErrors} },
* { code: "{code}", errors: ["{errorMessage}"] },
* { code: "{code}", options: {options}, globals: {globals}, parser: "{parser}", settings: {settings}, errors: [{ message: "{errorMessage}", type: "{errorNodeType}"}] }
* ]
* });
*
* Variables:
* {code} - String that represents the code to be tested
* {options} - Arguments that are passed to the configurable rules.
* {globals} - An object representing a list of variables that are
* registered as globals
* {parser} - String representing the parser to use
* {settings} - An object representing global settings for all rules
* {numErrors} - If failing case doesn't need to check error message,
* this integer will specify how many errors should be
* received
* {errorMessage} - Message that is returned by the rule on failure
* {errorNodeType} - AST node type that is returned by they rule as
* a cause of the failure.
*/
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const lodash = require("lodash"),
assert = require("assert"),
util = require("util"),
validator = require("../config/config-validator"),
ajv = require("../util/ajv"),
Linter = require("../linter"),
Environments = require("../config/environments"),
SourceCodeFixer = require("../util/source-code-fixer"),
interpolate = require("../util/interpolate");
//------------------------------------------------------------------------------
// Private Members
//------------------------------------------------------------------------------
/*
* testerDefaultConfig must not be modified as it allows to reset the tester to
* the initial default configuration
*/
const testerDefaultConfig = { rules: {} };
let defaultConfig = { rules: {} };
/*
* List every parameters possible on a test case that are not related to eslint
* configuration
*/
const RuleTesterParameters = [
"code",
"filename",
"options",
"errors",
"output"
];
const hasOwnProperty = Function.call.bind(Object.hasOwnProperty);
/**
* Clones a given value deeply.
* Note: This ignores `parent` property.
*
* @param {any} x - A value to clone.
* @returns {any} A cloned value.
*/
function cloneDeeplyExcludesParent(x) {
if (typeof x === "object" && x !== null) {
if (Array.isArray(x)) {
return x.map(cloneDeeplyExcludesParent);
}
const retv = {};
for (const key in x) {
if (key !== "parent" && hasOwnProperty(x, key)) {
retv[key] = cloneDeeplyExcludesParent(x[key]);
}
}
return retv;
}
return x;
}
/**
* Freezes a given value deeply.
*
* @param {any} x - A value to freeze.
* @returns {void}
*/
function freezeDeeply(x) {
if (typeof x === "object" && x !== null) {
if (Array.isArray(x)) {
x.forEach(freezeDeeply);
} else {
for (const key in x) {
if (key !== "parent" && hasOwnProperty(x, key)) {
freezeDeeply(x[key]);
}
}
}
Object.freeze(x);
}
}
//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------
// default separators for testing
const DESCRIBE = Symbol("describe");
const IT = Symbol("it");
/**
* This is `it` default handler if `it` don't exist.
* @this {Mocha}
* @param {string} text - The description of the test case.
* @param {Function} method - The logic of the test case.
* @returns {any} Returned value of `method`.
*/
function itDefaultHandler(text, method) {
try {
return method.call(this);
} catch (err) {
if (err instanceof assert.AssertionError) {
err.message += ` (${util.inspect(err.actual)} ${err.operator} ${util.inspect(err.expected)})`;
}
throw err;
}
}
/**
* This is `describe` default handler if `describe` don't exist.
* @this {Mocha}
* @param {string} text - The description of the test case.
* @param {Function} method - The logic of the test case.
* @returns {any} Returned value of `method`.
*/
function describeDefaultHandler(text, method) {
return method.call(this);
}
class RuleTester {
/**
* Creates a new instance of RuleTester.
* @param {Object} [testerConfig] Optional, extra configuration for the tester
* @constructor
*/
constructor(testerConfig) {
/**
* The configuration to use for this tester. Combination of the tester
* configuration and the default configuration.
* @type {Object}
*/
this.testerConfig = lodash.merge(
// we have to clone because merge uses the first argument for recipient
lodash.cloneDeep(defaultConfig),
testerConfig,
{ rules: { "rule-tester/validate-ast": "error" } }
);
/**
* Rule definitions to define before tests.
* @type {Object}
*/
this.rules = {};
this.linter = new Linter();
}
/**
* Set the configuration to use for all future tests
* @param {Object} config the configuration to use.
* @returns {void}
*/
static setDefaultConfig(config) {
if (typeof config !== "object") {
throw new TypeError("RuleTester.setDefaultConfig: config must be an object");
}
defaultConfig = config;
// Make sure the rules object exists since it is assumed to exist later
defaultConfig.rules = defaultConfig.rules || {};
}
/**
* Get the current configuration used for all tests
* @returns {Object} the current configuration
*/
static getDefaultConfig() {
return defaultConfig;
}
/**
* Reset the configuration to the initial configuration of the tester removing
* any changes made until now.
* @returns {void}
*/
static resetDefaultConfig() {
defaultConfig = lodash.cloneDeep(testerDefaultConfig);
}
/*
* If people use `mocha test.js --watch` command, `describe` and `it` function
* instances are different for each execution. So `describe` and `it` should get fresh instance
* always.
*/
static get describe() {
return (
this[DESCRIBE] ||
(typeof describe === "function" ? describe : describeDefaultHandler)
);
}
static set describe(value) {
this[DESCRIBE] = value;
}
static get it() {
return (
this[IT] ||
(typeof it === "function" ? it : itDefaultHandler)
);
}
static set it(value) {
this[IT] = value;
}
/**
* Define a rule for one particular run of tests.
* @param {string} name The name of the rule to define.
* @param {Function} rule The rule definition.
* @returns {void}
*/
defineRule(name, rule) {
this.rules[name] = rule;
}
/**
* Adds a new rule test to execute.
* @param {string} ruleName The name of the rule to run.
* @param {Function} rule The rule to test.
* @param {Object} test The collection of tests to run.
* @returns {void}
*/
run(ruleName, rule, test) {
const testerConfig = this.testerConfig,
requiredScenarios = ["valid", "invalid"],
scenarioErrors = [],
linter = this.linter;
if (lodash.isNil(test) || typeof test !== "object") {
throw new TypeError(`Test Scenarios for rule ${ruleName} : Could not find test scenario object`);
}
requiredScenarios.forEach(scenarioType => {
if (lodash.isNil(test[scenarioType])) {
scenarioErrors.push(`Could not find any ${scenarioType} test scenarios`);
}
});
if (scenarioErrors.length > 0) {
throw new Error([
`Test Scenarios for rule ${ruleName} is invalid:`
].concat(scenarioErrors).join("\n"));
}
linter.defineRule(ruleName, Object.assign({}, rule, {
// Create a wrapper rule that freezes the `context` properties.
create(context) {
freezeDeeply(context.options);
freezeDeeply(context.settings);
freezeDeeply(context.parserOptions);
return (typeof rule === "function" ? rule : rule.create)(context);
}
}));
linter.defineRules(this.rules);
const ruleMap = linter.getRules();
/**
* Run the rule for the given item
* @param {string|Object} item Item to run the rule against
* @returns {Object} Eslint run result
* @private
*/
function runRuleForItem(item) {
let config = lodash.cloneDeep(testerConfig),
code, filename, beforeAST, afterAST;
if (typeof item === "string") {
code = item;
} else {
code = item.code;
/*
* Assumes everything on the item is a config except for the
* parameters used by this tester
*/
const itemConfig = lodash.omit(item, RuleTesterParameters);
/*
* Create the config object from the tester config and this item
* specific configurations.
*/
config = lodash.merge(
config,
itemConfig
);
}
if (item.filename) {
filename = item.filename;
}
if (Object.prototype.hasOwnProperty.call(item, "options")) {
assert(Array.isArray(item.options), "options must be an array");
config.rules[ruleName] = [1].concat(item.options);
} else {
config.rules[ruleName] = 1;
}
const schema = validator.getRuleOptionsSchema(rule);
/*
* Setup AST getters.
* The goal is to check whether or not AST was modified when
* running the rule under test.
*/
linter.defineRule("rule-tester/validate-ast", () => ({
Program(node) {
beforeAST = cloneDeeplyExcludesParent(node);
},
"Program:exit"(node) {
afterAST = node;
}
}));
if (schema) {
ajv.validateSchema(schema);
if (ajv.errors) {
const errors = ajv.errors.map(error => {
const field = error.dataPath[0] === "." ? error.dataPath.slice(1) : error.dataPath;
return `\t${field}: ${error.message}`;
}).join("\n");
throw new Error([`Schema for rule ${ruleName} is invalid:`, errors]);
}
}
validator.validate(config, "rule-tester", ruleMap.get.bind(ruleMap), new Environments());
return {
messages: linter.verify(code, config, filename, true),
beforeAST,
afterAST: cloneDeeplyExcludesParent(afterAST)
};
}
/**
* Check if the AST was changed
* @param {ASTNode} beforeAST AST node before running
* @param {ASTNode} afterAST AST node after running
* @returns {void}
* @private
*/
function assertASTDidntChange(beforeAST, afterAST) {
if (!lodash.isEqual(beforeAST, afterAST)) {
assert.fail("Rule should not modify AST.");
}
}
/**
* Check if the template is valid or not
* all valid cases go through this
* @param {string|Object} item Item to run the rule against
* @returns {void}
* @private
*/
function testValidTemplate(item) {
const result = runRuleForItem(item);
const messages = result.messages;
assert.strictEqual(messages.length, 0, util.format("Should have no errors but had %d: %s",
messages.length, util.inspect(messages)));
assertASTDidntChange(result.beforeAST, result.afterAST);
}
/**
* Asserts that the message matches its expected value. If the expected
* value is a regular expression, it is checked against the actual
* value.
* @param {string} actual Actual value
* @param {string|RegExp} expected Expected value
* @returns {void}
* @private
*/
function assertMessageMatches(actual, expected) {
if (expected instanceof RegExp) {
// assert.js doesn't have a built-in RegExp match function
assert.ok(
expected.test(actual),
`Expected '${actual}' to match ${expected}`
);
} else {
assert.strictEqual(actual, expected);
}
}
/**
* Check if the template is invalid or not
* all invalid cases go through this.
* @param {string|Object} item Item to run the rule against
* @returns {void}
* @private
*/
function testInvalidTemplate(item) {
assert.ok(item.errors || item.errors === 0,
`Did not specify errors for an invalid test of ${ruleName}`);
const result = runRuleForItem(item);
const messages = result.messages;
if (typeof item.errors === "number") {
assert.strictEqual(messages.length, item.errors, util.format("Should have %d error%s but had %d: %s",
item.errors, item.errors === 1 ? "" : "s", messages.length, util.inspect(messages)));
} else {
assert.strictEqual(
messages.length, item.errors.length,
util.format(
"Should have %d error%s but had %d: %s",
item.errors.length, item.errors.length === 1 ? "" : "s", messages.length, util.inspect(messages)
)
);
const hasMessageOfThisRule = messages.some(m => m.ruleId === ruleName);
for (let i = 0, l = item.errors.length; i < l; i++) {
const error = item.errors[i];
const message = messages[i];
assert(!message.fatal, `A fatal parsing error occurred: ${message.message}`);
assert(hasMessageOfThisRule, "Error rule name should be the same as the name of the rule being tested");
if (typeof error === "string" || error instanceof RegExp) {
// Just an error message.
assertMessageMatches(message.message, error);
} else if (typeof error === "object") {
/*
* Error object.
* This may have a message, messageId, data, node type, line, and/or
* column.
*/
if (hasOwnProperty(error, "message")) {
assert.ok(!hasOwnProperty(error, "messageId"), "Error should not specify both 'message' and a 'messageId'.");
assert.ok(!hasOwnProperty(error, "data"), "Error should not specify both 'data' and 'message'.");
assertMessageMatches(message.message, error.message);
} else if (hasOwnProperty(error, "messageId")) {
assert.ok(
hasOwnProperty(rule, "meta") && hasOwnProperty(rule.meta, "messages"),
"Error can not use 'messageId' if rule under test doesn't define 'meta.messages'."
);
if (!hasOwnProperty(rule.meta.messages, error.messageId)) {
const friendlyIDList = `[${Object.keys(rule.meta.messages).map(key => `'${key}'`).join(", ")}]`;
assert(false, `Invalid messageId '${error.messageId}'. Expected one of ${friendlyIDList}.`);
}
assert.strictEqual(
error.messageId,
message.messageId,
`messageId '${message.messageId}' does not match expected messageId '${error.messageId}'.`
);
if (hasOwnProperty(error, "data")) {
/*
* if data was provided, then directly compare the returned message to a synthetic
* interpolated message using the same message ID and data provided in the test.
* See https://github.com/eslint/eslint/issues/9890 for context.
*/
const unformattedOriginalMessage = rule.meta.messages[error.messageId];
const rehydratedMessage = interpolate(unformattedOriginalMessage, error.data);
assert.strictEqual(
message.message,
rehydratedMessage,
`Hydrated message "${rehydratedMessage}" does not match "${message.message}"`
);
}
}
assert.ok(
hasOwnProperty(error, "data") ? hasOwnProperty(error, "messageId") : true,
"Error must specify 'messageId' if 'data' is used."
);
if (error.type) {
assert.strictEqual(message.nodeType, error.type, `Error type should be ${error.type}, found ${message.nodeType}`);
}
if (Object.prototype.hasOwnProperty.call(error, "line")) {
assert.strictEqual(message.line, error.line, `Error line should be ${error.line}`);
}
if (Object.prototype.hasOwnProperty.call(error, "column")) {
assert.strictEqual(message.column, error.column, `Error column should be ${error.column}`);
}
if (Object.prototype.hasOwnProperty.call(error, "endLine")) {
assert.strictEqual(message.endLine, error.endLine, `Error endLine should be ${error.endLine}`);
}
if (Object.prototype.hasOwnProperty.call(error, "endColumn")) {
assert.strictEqual(message.endColumn, error.endColumn, `Error endColumn should be ${error.endColumn}`);
}
} else {
// Message was an unexpected type
assert.fail(`Error should be a string, object, or RegExp, but found (${util.inspect(message)})`);
}
}
}
if (Object.prototype.hasOwnProperty.call(item, "output")) {
if (item.output === null) {
assert.strictEqual(
messages.filter(message => message.fix).length,
0,
"Expected no autofixes to be suggested"
);
} else {
const fixResult = SourceCodeFixer.applyFixes(item.code, messages);
assert.strictEqual(fixResult.output, item.output, "Output is incorrect.");
}
}
assertASTDidntChange(result.beforeAST, result.afterAST);
}
/*
* This creates a mocha test suite and pipes all supplied info through
* one of the templates above.
*/
RuleTester.describe(ruleName, () => {
RuleTester.describe("valid", () => {
test.valid.forEach(valid => {
RuleTester.it(typeof valid === "object" ? valid.code : valid, () => {
testValidTemplate(valid);
});
});
});
RuleTester.describe("invalid", () => {
test.invalid.forEach(invalid => {
RuleTester.it(invalid.code, () => {
testInvalidTemplate(invalid);
});
});
});
});
}
}
RuleTester[DESCRIBE] = RuleTester[IT] = null;
module.exports = RuleTester;