LibJS/test-js: Create test-js program, prepare for test suite refactor

This moves most of the work from run-tests.sh to test-js.cpp. This way,
we have a lot more control over how the test suite runs, as well as how
it outputs. This should result in some cool functionality!

This commit also refactors test-common.js to mimic the jest library.
This should allow tests to be much more expressive :)

1 files changed, 338 insertions, 102 deletions

diff --git a/Libraries/LibJS/Tests/test-common.js b/Libraries/LibJS/Tests/test-common.js
index 4c7e23ac8b..d109988bca 100644
--- a/Libraries/LibJS/Tests/test-common.js
+++ b/Libraries/LibJS/Tests/test-common.js
@@ -1,116 +1,34 @@
-/**
- * Custom error for failed assertions.
- * @constructor
- * @param {string} message Error message
- * @returns Error
- */
-function AssertionError(message) {
-    var instance = new Error(message);
-    instance.name = 'AssertionError';
-    Object.setPrototypeOf(instance, Object.getPrototypeOf(this));
-    return instance;
-}
-
-/**
- * Throws an `AssertionError` if `value` is not truthy.
- * @param {*} value Value to be tested
- */
-function assert(value) {
-    if (!value)
-        throw new AssertionError("The assertion failed!");
-}
+let describe;
+let test;
+let expect;
 
-/**
- * Throws an `AssertionError` when called.
- * @throws {AssertionError}
- */
-function assertNotReached() {
-    throw new AssertionError("assertNotReached() was reached!");
-}
+// Stores the results of each test and suite. Has a terrible
+// name to avoid name collision.
+let __TestResults__ = {};
 
-/**
- * Ensures the provided functions throws a specific error.
- * @param {Function} testFunction Function executing the throwing code
- * @param {object} [options]
- * @param {Error} [options.error] Expected error type
- * @param {string} [options.name] Expected error name
- * @param {string} [options.message] Expected error message
- */
-function assertThrowsError(testFunction, options) {
-    try {
-        testFunction();
-        assertNotReached();
-    } catch (e) {
-        if (options.error !== undefined)
-            assert(e instanceof options.error);
-        if (options.name !== undefined)
-            assert(e.name === options.name);
-        if (options.message !== undefined)
-            assert(e.message === options.message);
-    }
-}
-
-/**
- * Ensures the provided JavaScript source code results in a SyntaxError
- * @param {string} source The JavaScript source code to compile
- */
-function assertIsSyntaxError(source) {
-    assertThrowsError(() => {
-        new Function(source)();
-    }, {
-        error: SyntaxError,
-    });
-}
-
-/**
- * Ensures the provided arrays contain exactly the same items.
- * @param {Array} a First array
- * @param {Array} b Second array
- */
-function assertArrayEquals(a, b) {
-    if (a.length != b.length)
-        throw new AssertionError("Array lengths do not match");
-    
-    for (var i = 0; i < a.length; i++) {
-        if (a[i] !== b[i])
-            throw new AssertionError("Elements do not match");
-    }
-}
+// This array is used to communicate with the C++ program. It treats
+// each message in this array as a separate message. Has a terrible
+// name to avoid name collision.
+let __UserOutput__ = [];
 
-const assertVisitsAll = (testFunction, expectedOutput) => {
-    const visited = [];
-    testFunction(value => visited.push(value));
-    assert(visited.length === expectedOutput.length);
-    expectedOutput.forEach((value, i) => assert(visited[i] === value));
+// We also rebind console.log here to use the array above
+console.log = (...args) => {
+    __UserOutput__.push(args.join(" "));
 };
 
-/**
- * Check whether the difference between two numbers is less than 0.000001.
- * @param {Number} a First number
- * @param {Number} b Second number
- */
-function isClose(a, b) {
-    return Math.abs(a - b) < 0.000001;
-}
-
-/**
- * Quick and dirty deep equals method.
- * @param {*} a First value
- * @param {*} b Second value
- */
-function assertDeepEquals(a, b) {
-    assert(deepEquals(a, b));
-}
+// Use an IIFE to avoid polluting the global namespace as much as possible
+(() => {
 
-function deepEquals(a, b) {
+// FIXME: This is a very naive deepEquals algorithm
+const deepEquals = (a, b) => {
     if (Array.isArray(a))
         return Array.isArray(b) && deepArrayEquals(a, b);
     if (typeof a === "object")
         return typeof b === "object" && deepObjectEquals(a, b);
-    return a === b;
+    return Object.is(a, b);
 }
 
-function deepArrayEquals(a, b) {
+const deepArrayEquals = (a, b) => {
     if (a.length !== b.length)
         return false;
     for (let i = 0; i < a.length; ++i) {
@@ -120,7 +38,7 @@ function deepArrayEquals(a, b) {
     return true;
 }
 
-function deepObjectEquals(a, b) {
+const deepObjectEquals = (a, b) => {
     if (a === null)
         return b === null;
     for (let key of Reflect.ownKeys(a)) {
@@ -129,3 +47,321 @@ function deepObjectEquals(a, b) {
     }
     return true;
 }
+
+class ExpectationError extends Error {
+    constructor(message, fileName, lineNumber) {
+        super(message, fileName, lineNumber);
+        this.name = "ExpectationError";
+    }
+}
+
+class Expector {
+    constructor(target, inverted) {
+        this.target = target;
+        this.inverted = !!inverted;
+    }
+
+    get not() {
+        return new Expector(this.target, !this.inverted);
+    }
+
+    toBe(value) {
+        this.__doMatcher(() => {
+            this.__expect(Object.is(this.target, value));
+        });
+    }
+
+    toHaveLength(length) {
+        this.__doMatcher(() => {
+            this.__expect(Object.is(this.target.length, length));
+        });
+    }
+
+    toHaveProperty(property, value) {
+        this.__doMatcher(() => {
+            let object = this.target;
+    
+            if (typeof property === "string" && property.includes(".")) {
+                let propertyArray = [];
+    
+                while (true) {
+                    let index = property.indexOf(".");
+                    if (index === -1) {
+                        propertyArray.push(property);
+                        break;
+                    }
+    
+                    propertyArray.push(property.substring(0, index));
+                    property = property.substring(index, property.length);
+                }
+    
+                property = propertyArray;
+            }
+    
+            if (Array.isArray(property)) {
+                for (let key of property) {
+                    if (object === undefined || object === null) {
+                        if (this.inverted)
+                            return;
+                        throw new ExpectationError();
+                    }
+                    object = object[key];
+                }
+            } else {
+                object = object[property];
+            }
+
+            this.__expect(object !== undefined);
+            if (value !== undefined)
+                this.__expect(deepEquals(object, value));
+        });
+    }
+
+    toBeCloseTo(number, numDigits) {
+        if (numDigits === undefined)
+            numDigits = 2;
+
+        this.__doMatcher(() => {
+            this.__expect(Math.abs(number - this.target) < (10 ** -numDigits / numDigits));
+        });
+    }
+
+    toBeDefined() {
+        this.__doMatcher(() => {
+            this.__expect(this.target !== undefined);
+        });
+    }
+
+    toBeFalsey() {
+        this.__doMatcher(() => {
+            this.__expect(!this.target);
+        });
+    }
+
+    toBeGreaterThan(number) {
+        this.__doMatcher(() => {
+            this.__expect(this.target > number);
+        });
+    }
+
+    toBeGreaterThanOrEqual(number) {
+        this.__doMatcher(() => {
+            this.__expect(this.target >= number);
+        });
+    }
+
+    toBeLessThan(number) {
+        this.__doMatcher(() => {
+            this.__expect(this.target < number);
+        });
+    }
+
+    toBeLessThanOrEqual(number) {
+        this.__doMatcher(() => {
+            this.__expect(this.target <= number);
+        });
+    }
+
+    toBeInstanceOf(class_) {
+        this.__doMatcher(() => {
+            this.__expect(this.target instanceof class_);
+        });
+    }
+
+    toBeNull() {
+        this.__doMatcher(() => {
+            this.__expect(this.target === null);
+        });
+    }
+
+    toBeTruthy() {
+        this.__doMatcher(() => {
+            this.__expect(!!this.target);
+        });
+    }
+
+    toBeUndefined() {
+        this.__doMatcher(() => {
+            this.__expect(this.target === undefined);
+        });
+    }
+
+    toBeNaN() {
+        this.__doMatcher(() => {
+            this.__expect(isNaN(this.target));
+        });
+    }
+
+    toContain(item) {
+        this.__doMatcher(() => {
+            // FIXME: Iterator check
+            for (let element of this.target) {
+                if (item === element)
+                    return;
+            }
+            
+            throw new ExpectationError();
+        });
+    }
+
+    toContainEqual(item) {
+        this.__doMatcher(() => {
+            // FIXME: Iterator check
+            for (let element of this.target) {
+                if (deepEquals(item, element))
+                    return;
+            }
+            
+            throw new ExpectationError();
+        });
+    }
+
+    toEqual(value) {
+        this.__doMatcher(() => {
+            this.__expect(deepEquals(this.target, value));
+        });
+    }
+
+    toThrow(value) {
+        this.__expect(typeof this.target === "function");
+        this.__expect(typeof value === "string" || typeof value === "function" || value === undefined);
+
+        this.__doMatcher(() => {
+            try {
+                this.target();
+                this.__expect(false);
+            } catch (e) {
+                if (typeof value === "string") {
+                    this.__expect(e.message.includes(value));
+                } else if (typeof value === "function") {
+                    this.__expect(e instanceof value);
+                }
+            }
+        });
+    }
+
+    pass(message) {
+        // FIXME: This does nothing. If we want to implement things
+        // like assertion count, this will have to do something
+    }
+
+    // jest-extended
+    fail(message) {
+        // FIXME: message is currently ignored
+        this.__doMatcher(() => {
+            this.__expect(false);
+        })
+    }
+
+    // jest-extended
+    toThrowWithMessage(class_, message) {
+        this.__expect(typeof this.target === "function");
+        this.__expect(class_ !== undefined);
+        this.__expect(message !== undefined);
+
+        this.__doMatcher(() => {
+            try {
+                this.target();
+                this.__expect(false);
+            } catch (e) {
+                this.__expect(e instanceof class_);
+                this.__expect(e.message.includes(message));
+            }
+        });
+    }
+
+    // Test for syntax errors; target must be a string
+    toEval() {
+        this.__expect(typeof this.target === "string");
+
+        if (!this.inverted) {
+            try {
+                new Function(this.target)();
+            } catch (e) {
+                throw new ExpectationError();
+            }
+        } else {
+            try {
+                new Function(this.target)();
+                throw new ExpectationError();
+            } catch (e) {
+                if (e.name !== "SyntaxError") 
+                    throw new ExpectationError();
+            }
+        }
+    }
+
+    // Must compile regardless of inverted-ness
+    toEvalTo(value) {
+        this.__expect(typeof this.target === "string");
+
+        let result;
+
+        try {
+            result = new Function(this.target)();
+        } catch (e) {
+            throw new ExpectationError();
+        }
+
+        this.__doMatcher(() => {
+            this.__expect(deepEquals(value, result));
+        });
+    }
+
+    __doMatcher(matcher) {
+        if (!this.inverted) {
+            matcher();
+        } else {
+            let threw = false;
+            try {
+                matcher();
+            } catch (e) {
+                if (e.name === "ExpectationError")
+                    threw = true;
+            }
+            if (!threw)
+                throw new ExpectationError();
+        }
+    }
+
+    __expect(value) {
+        if (value !== true)
+            throw new ExpectationError();
+    }
+}
+
+expect = value => new Expector(value);
+
+// describe is able to lump test results inside of it by using this context
+// variable. Top level tests are assumed to be in the default context
+const defaultSuiteMessage = "__$$TOP_LEVEL$$__";
+let suiteMessage = defaultSuiteMessage;
+
+describe = (message, callback) => {
+    suiteMessage = message;
+    callback();
+    suiteMessage = defaultSuiteMessage;
+}
+
+test = (message, callback) => {
+    if (!__TestResults__[suiteMessage])
+        __TestResults__[suiteMessage] = {};
+
+    const suite = __TestResults__[suiteMessage];
+
+    if (!suite[message])
+        suite[message] = {};
+
+    try {
+        callback();
+        suite[message] = {
+            passed: true,
+        };
+    } catch (e) {
+        suite[message] = {
+            passed: false,
+        };
+    }
+}
+
+})();