Dependency free assert module with unit tests

Author: grayrest

lib/assert.js

@@ -1,21 +1,72 @@
-var sys = require('sys');
-var util = require('util');
+// http://wiki.commonjs.org/wiki/Unit_Testing/1.0
+//
+// THIS IS NOT TESTED NOR LIKELY TO WORK OUTSIDE V8!
+//
+// Originally from narwhal.js (http://narwhaljs.org)
+// Copyright (c) 2009 Thomas Robinson <280north.com>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the “Software”), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// UTILITY
+
+var pSlice = Array.prototype.slice;
+
+// 1. The assert module provides functions that throw
+// AssertionError's when particular conditions are not met. The
+// assert module must conform to the following interface.
+
 var assert = exports;
 
-assert.AssertionError = function (options) {
+// 2. The AssertionError is defined in assert.
+// new assert.AssertionError({message: message, actual: actual, expected: expected})
+
+assert.AssertionError = function AssertionError(options) {
     this.name = "AssertionError";
     this.message = options.message;
     this.actual = options.actual;
     this.expected = options.expected;
     this.operator = options.operator;
-
-    Error.captureStackTrace(this, fail);
+    //v8 specific
+    if(Error.captureStackTrace){
+        Error.captureStackTrace(this,fail);
+        //node specific, removes the node machinery stack frames
+        if(typeof(__filename) !== undefined){
+            var stack = this.stack.split('\n');
+            for (var i = stack.length - 1; i >= 0; i--) {
+                if(stack[i].indexOf(__filename) != -1){
+                    this.stack = stack.slice(0,i+2).join('\n');
+                    break;
+                }
+            }
+        }
+    }
 };
-sys.inherits(assert.AssertionError, Error);
+
+assert.AssertionError.prototype.toString = function(){
+    if(this.message)
+        return [this.name+":", this.message].join(' ');
+    else
+        return [this.name+":", JSON.stringify(this.expected ), this.operator , JSON.stringify(this.actual)].join(" ");
+}
 
 // assert.AssertionError instanceof Error
 
-// assert.AssertionError.prototype = Object.create(Error.prototype);
+assert.AssertionError.__proto__ = Error.prototype;
 
 // At present only the three keys mentioned above are used and
 // understood by the spec. Implementations or sub modules can pass
@@ -37,14 +88,17 @@ function fail(actual, expected, message, operator) {
     });
 }
 
+// EXTENSION! allows for well behaved errors defined elsewhere.
+assert.fail = fail;
+
 // 4. Pure assertion tests whether a value is truthy, as determined
 // by !!guard.
 // assert.ok(guard, message_opt);
 // This statement is equivalent to assert.equal(true, guard,
 // message_opt);. To test strictly for the value true, use
 // assert.strictEqual(true, guard, message_opt);.
 
-assert.ok = function (value, message) {
+assert.ok = function ok(value, message) {
     if (!!!value)
         fail(value, true, message, "==");
 };
@@ -53,7 +107,7 @@ assert.ok = function (value, message) {
 // ==.
 // assert.equal(actual, expected, message_opt);
 
-assert.equal = function (actual, expected, message) {
+assert.equal = function equal(actual, expected, message) {
     if (actual != expected)
         fail(actual, expected, message, "==");
 };
@@ -62,21 +116,20 @@ assert.equal = function (actual, expected, message) {
 // 6. The non-equality assertion tests for whether two objects are not equal
 // with != assert.notEqual(actual, expected, message_opt);
 
-assert.notEqual = function (actual, expected, message) {
+assert.notEqual = function notEqual(actual, expected, message) {
     if (actual == expected)
         fail(actual, expected, message, "!=");
 };
 
 // 7. The equivalence assertion tests a deep equality relation.
 // assert.deepEqual(actual, expected, message_opt);
 
-exports.deepEqual = function (actual, expected, message) {
-    if (!deepEqual(actual, expected))
+exports.deepEqual = function deepEqual(actual, expected, message) {
+    if (!_deepEqual(actual, expected))
         fail(actual, expected, message, "deepEqual");
 };
 
-function deepEqual(actual, expected) {
-    
+function _deepEqual(actual, expected) {
     // 7.1. All identical values are equivalent, as determined by ===.
     if (actual === expected) {
         return true;
@@ -85,7 +138,7 @@ function deepEqual(actual, expected) {
     // equivalent if it is also a Date object that refers to the same time.
     } else if (actual instanceof Date
             && expected instanceof Date) {
-        return actual.toValue() === expected.toValue();
+        return actual.getTime() === expected.getTime();
 
     // 7.3. Other pairs that do not both pass typeof value == "object",
     // equivalence is determined by ==.
@@ -100,68 +153,113 @@ function deepEqual(actual, expected) {
     // corresponding key, and an identical "prototype" property. Note: this
     // accounts for both named and indexed properties on Arrays.
     } else {
-        return actual.prototype === expected.prototype && objEquiv(actual, expected);
+        return objEquiv(actual, expected);
     }
 }
 
-function objEquiv(a, b, stack) {
-    return (
-        !util.no(a) && !util.no(b) &&
-        arrayEquiv(
-            util.sort(util.object.keys(a)),
-            util.sort(util.object.keys(b))
-        ) &&
-        util.object.keys(a).every(function (key) {
-            return deepEqual(a[key], b[key], stack);
-        })
-    );
+function isUndefinedOrNull (value) {
+    return value === null || value === undefined;
 }
 
-function arrayEquiv(a, b, stack) {
-    return util.isArrayLike(b) &&
-        a.length == b.length &&
-        util.zip(a, b).every(util.apply(function (a, b) {
-            return deepEqual(a, b, stack);
-        }));
+function isArguments (object){
+    return Object.prototype.toString.call(object) == '[object Arguments]';
+}
+
+function objEquiv (a, b) {
+    if (isUndefinedOrNull(a) || isUndefinedOrNull(b))
+        return false;
+    // an identical "prototype" property.
+    if (a.prototype !== b.prototype) return false;
+    //~~~I've managed to break Object.keys through screwy arguments passing.
+    //   Converting to array solves the problem.
+    if(isArguments(a)){
+        if(!isArguments(b)){
+            return false;
+        }
+        a = pSlice.call(a);
+        b = pSlice.call(b);
+        return _deepEqual(a,b);
+    }
+    try{
+        var ka = Object.keys(a),
+            kb = Object.keys(b),
+            key, i;
+    } catch (e) {//happens when one is a string literal and the other isn't
+        return false;
+    }
+    // having the same number of owned properties (keys incorporates hasOwnProperty)
+    if(ka.length != kb.length)
+        return false;
+    //the same set of keys (although not necessarily the same order),
+    ka.sort();
+    kb.sort();
+    //~~~cheap key test
+    for (i = ka.length - 1; i >= 0; i--) {
+        if(ka[i] != kb[i])
+            return false;
+    }
+    //equivalent values for every corresponding key, and
+    //~~~possibly expensive deep test
+    for (i = ka.length - 1; i >= 0; i--) {
+        key = ka[i];
+        if(!_deepEqual(a[key], b[key] ))
+           return false;
+    }
+    return true;
 }
 
 // 8. The non-equivalence assertion tests for any deep inequality.
 // assert.notDeepEqual(actual, expected, message_opt);
 
-exports.notDeepEqual = function (actual, expected, message) {
-    if (deepEqual(actual, expected))
+exports.notDeepEqual = function notDeepEqual(actual, expected, message) {
+    if (_deepEqual(actual, expected))
         fail(actual, expected, message, "notDeepEqual");
 };
 
 // 9. The strict equality assertion tests strict equality, as determined by ===.
 // assert.strictEqual(actual, expected, message_opt);
 
-assert.strictEqual = function (actual, expected, message) {
+assert.strictEqual = function strictEqual(actual, expected, message) {
     if (actual !== expected)
         fail(actual, expected, message, "===");
 };
 
 // 10. The strict non-equality assertion tests for strict inequality, as determined by !==.
 // assert.notStrictEqual(actual, expected, message_opt);
 
-assert.notStrictEqual = function (actual, expected, message) {
+assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
     if (actual === expected)
         fail(actual, expected, message, "!==");
 };
 
 // 11. Expected to throw an error:
 // assert.throws(block, Error_opt, message_opt);
 
-assert["throws"] = function (block, Error, message) {
-    var threw = false,
-        exception = null;
-        
-    if (typeof Error == "string") {
-        message = Error;
-        Error = undefined;
-    } else {
-        Error = message;
-        message = "";
+assert.throws = function(block, /*optional*/error, /*optional*/message){
+    var args = [true]
+    _throws.apply(this, args.concat(pSlice.call(arguments)));
+}
+
+// EXTENSION! This is annoying to write outside this module.
+assert.doesNotThrow = function(block, /*optional*/error, /*optional*/message){
+    var args = [false]
+    _throws.apply(this, args.concat(pSlice.call(arguments)));
+}
+
+var _throws = function (shouldThrow, block, err, message) {
+    var exception = null
+        threw = false
+        typematters = true;
+    message = message || "";
+
+    //handle optional arguments
+    if(arguments.length == 3){
+        if(typeof(err) == "string"){
+            message = err;
+            typematters = false;
+        }
+    } else if(arguments.length == 2) {
+        typematters = false;
     }
 
     try {
@@ -170,7 +268,19 @@ assert["throws"] = function (block, Error, message) {
         threw = true;
         exception = e;
     }
-    
-    if (!threw)
-        fail("Expected exception" + (message ? ": " + message : ""));
+
+    if(shouldThrow && !threw){
+        fail("Missing expected exception"+
+             (err && err.name ? " ("+err.name+")." : '.') +
+             (message ? " " + message : ""));
+    }
+    if(!shouldThrow && threw && typematters && exception instanceof err){
+        fail("Got unwanted exception" +
+             (err && err.name ? " ("+err.name+")." : '.') +
+             (message ? " " + message : ""));
+    }
+    if((shouldThrow && threw && typematters && !(exception instanceof err)) ||
+       (!shouldThrow && threw)){
+        throw exception;
+    }
 };