BREAKING CHANGE: remove assert.failException property

This was used for allowing customisation of the thrown error between
sandboxes and for customisation for integrations (most likely from the
days of BusterJS).

To my knowledge and what I've been able to find on GitHub, this has
never had any _production_ use by end users.

Author: mroderick

lib/sinon/assert.js

@@ -47,8 +47,6 @@ function createAssertObject(opts) {
     });
 
     const assert = {
-        failException: "AssertError",
-
         fail: function fail(message) {
             let msg = message;
             if (cleanedAssertOptions.shouldLimitAssertionLogs) {
@@ -58,7 +56,7 @@ function createAssertObject(opts) {
                 );
             }
             const error = new Error(msg);
-            error.name = this.failException || assert.failException;
+            error.name = "AssertError";
 
             throw error;
         },

test/assert-test.js

@@ -57,14 +57,6 @@ describe("assert", function () {
     });
 
     describe(".fail", function () {
-        beforeEach(function () {
-            this.exceptionName = sinonAssert.failException;
-        });
-
-        afterEach(function () {
-            sinonAssert.failException = this.exceptionName;
-        });
-
         it("can be configured to limit the error message length", function () {
             const customAssert = sinonAssert.createAssertObject({
                 shouldLimitAssertionLogs: true,
@@ -87,17 +79,6 @@ describe("assert", function () {
                 },
             );
         });
-
-        it("throws configured exception type", function () {
-            sinonAssert.failException = "CustomError";
-
-            assert.exception(
-                function () {
-                    sinonAssert.fail("Some message");
-                },
-                { name: "CustomError" },
-            );
-        });
     });
 
     describe("with stubs", function () {
@@ -1352,7 +1333,6 @@ describe("assert", function () {
             sinonAssert.expose(test);
 
             assert.isFunction(test.fail);
-            assert.isString(test.failException);
             assert.isFunction(test.assertCalled);
             assert.isFunction(test.assertCalledOn);
             assert.isFunction(test.assertCalledWith);
@@ -1367,7 +1347,6 @@ describe("assert", function () {
                 includeFail: false,
             });
 
-            assert.equals(typeof failException, "undefined");
             /*eslint-disable no-undef*/
             assert.isFunction(assertCalled);
             assert.isFunction(assertCalledOn);
@@ -1401,7 +1380,6 @@ describe("assert", function () {
             sinonAssert.expose(test, { prefix: "" });
 
             assert.isFunction(test.fail);
-            assert.isString(test.failException);
             assert.isFunction(test.called);
             assert.isFunction(test.calledOn);
             assert.isFunction(test.calledWith);

test/sandbox-test.js

@@ -1965,31 +1965,4 @@ describe("Sandbox", function () {
             refute.equals(getter, spy.get);
         });
     });
-
-    describe(".assert", function () {
-        it("allows rebinding of .fail on a per-sandbox level", function () {
-            const sandboxA = createSandbox();
-            const sandboxB = createSandbox();
-
-            sandboxA.assert.failException = "CustomErrorA";
-            sandboxB.assert.failException = "CustomErrorB";
-
-            assert.exception(
-                function () {
-                    sandboxA.assert.fail("Some message");
-                },
-                { name: "CustomErrorA" },
-            );
-
-            assert.exception(
-                function () {
-                    sandboxB.assert.fail("Some message");
-                },
-                { name: "CustomErrorB" },
-            );
-
-            sandboxA.restore();
-            sandboxB.restore();
-        });
-    });
 });