.withContext() works with .not

spec/core/ExpectationSpec.js

@@ -570,6 +570,62 @@ describe("Expectation", function() {
         })
       );
     });
+
+    it("works with #not", function() {
+      var matchers = {
+          toFoo: function() {
+            return {
+              compare: function() { return { pass: true }; }
+            };
+          }
+        },
+        addExpectationResult = jasmine.createSpy("addExpectationResult"),
+        expectation = jasmineUnderTest.Expectation.Factory({
+          customMatchers: matchers,
+          util: jasmineUnderTest.matchersUtil,
+          actual: "an actual",
+          addExpectationResult: addExpectationResult
+        });
+  
+      expectation.withContext("Some context").not.toFoo();
+  
+      expect(addExpectationResult).toHaveBeenCalledWith(false,
+        jasmine.objectContaining({
+          message: "Some context: Expected 'an actual' not to foo."
+        })
+      );
+    });
+
+    it("works with #not and a custom message", function() {
+      var customError = new Error("I am a custom error");
+      var matchers = {
+          toFoo: function() {
+            return {
+              compare: function() {
+                return {
+                  pass: true,
+                  message: function() { return "I am a custom message"; },
+                  error: customError
+                };
+              }
+            };
+          }
+        },
+        addExpectationResult = jasmine.createSpy("addExpectationResult"),
+        expectation = jasmineUnderTest.Expectation.Factory({
+          actual: "an actual",
+          customMatchers: matchers,
+          addExpectationResult: addExpectationResult
+        });
+  
+      expectation.withContext("Some context").not.toFoo("hello");
+  
+      expect(addExpectationResult).toHaveBeenCalledWith(false, 
+        jasmine.objectContaining({
+          message: "Some context: I am a custom message",
+        })
+      );
+    });
   });
 });
 

src/core/Expectation.js

@@ -9,7 +9,7 @@ getJasmineRequireObj().Expectation = function(j$) {
     this.customEqualityTesters = options.customEqualityTesters || [];
     this.actual = options.actual;
     this.addExpectationResult = options.addExpectationResult || function(){};
-    this.isNot = options.isNot;
+    this.filters = new j$.ExpectationFilterChain();
 
     var customMatchers = options.customMatchers || {};
     for (var matcherName in customMatchers) {
@@ -32,12 +32,8 @@ getJasmineRequireObj().Expectation = function(j$) {
 
   Expectation.prototype.instantiateMatcher = function(matcherFactory) {
     var matcher = matcherFactory(this.util, this.customEqualityTesters);
-
-    if (this.filter && this.filter.selectComparisonFunc) {
-      return this.filter.selectComparisonFunc(matcher);
-    }
-
-    return matcher.compare;
+    var comparisonFunc = this.filters.selectComparisonFunc(matcher);
+    return comparisonFunc || matcher.compare;
   };
 
   Expectation.prototype.processResult = function(result, name, expected, args) {
@@ -62,16 +58,16 @@ getJasmineRequireObj().Expectation = function(j$) {
   };
 
   Expectation.prototype.buildMessage = function(result, name, args) {
-    var util = this.util;
+    var util = this.util,
+      msg;
 
     if (result.pass) {
       return '';
-    } else if (this.filter && this.filter.buildFailureMessage) {
-      return this.filter.buildFailureMessage(result, name, args, util, defaultMessage);
-    } else {
-      return defaultMessage();
     }
 
+    msg = this.filters.buildFailureMessage(result, name, args, util, defaultMessage);
+    return this.filters.modifyFailureMessage(msg || defaultMessage());
+
     function defaultMessage() {
       if (!result.message) {
         args = args.slice();
@@ -86,6 +82,12 @@ getJasmineRequireObj().Expectation = function(j$) {
     }
   };
 
+  Expectation.prototype.addFilter = function(filter) {
+    var result = Object.create(this);
+    result.filters = this.filters.addFilter(filter);
+    return result;
+  };
+
   Expectation.addCoreMatchers = function(matchers) {
     var prototype = Expectation.prototype;
     for (var matcherName in matchers) {
@@ -96,13 +98,12 @@ getJasmineRequireObj().Expectation = function(j$) {
 
   Expectation.Factory = function(options) {
     var expect = new Expectation(options || {});
-    expect.not = Object.create(expect);
-    expect.not.filter = negatingFilter;
+    expect.not = expect.addFilter(negatingFilter);
 
     expect.withContext = function(message) {
-      var filteredExpect = Object.create(expect);
-      filteredExpect.filter = new ContextAddingFilter(message);
-      return filteredExpect;
+      var result = this.addFilter(new ContextAddingFilter(message));
+      result.not = result.addFilter(negatingFilter);
+      return result;
     };
 
     return expect;
@@ -140,8 +141,8 @@ getJasmineRequireObj().Expectation = function(j$) {
     this.message = message;
   }
 
-  ContextAddingFilter.prototype.buildFailureMessage = function(result, matcherName, args, util, getDefaultMessage) {
-    return this.message + ': ' + getDefaultMessage();
+  ContextAddingFilter.prototype.modifyFailureMessage = function(msg) {
+    return this.message + ': ' + msg;
   };
 
   return Expectation;