harness/asyncHelpers.js: Further reduce the size of assert.throwsAsync

Author: gibson042

harness/asyncHelpers.js

@@ -51,59 +51,47 @@ function asyncTest(testFunc) {
 assert.throwsAsync = function (expectedErrorConstructor, func, message) {
   return new Promise(function (resolve) {
     var expectedName = expectedErrorConstructor.name;
+    var expectation = "Expected a " + expectedName + " to be thrown asynchronously";
     var fail = function (detail) {
       if (message === undefined) {
         throw new Test262Error(detail);
       }
       throw new Test262Error(message + " " + detail);
     };
-    var innerThenable;
+    var res;
     if (typeof func !== "function") {
       fail("assert.throwsAsync called with an argument that is not a function");
     }
     try {
-      innerThenable = func();
+      res = func();
     } catch (thrown) {
-      fail("Expected a " +
-        expectedName +
-        " to be thrown asynchronously but the function threw synchronously");
+      fail(expectation + " but the function threw synchronously");
     }
-    if (
-      innerThenable === null ||
-      typeof innerThenable !== "object" ||
-      typeof innerThenable.then !== "function"
-    ) {
-      fail("Expected to obtain a promise that would reject with a " +
-        expectedName +
-        " but result was not a thenable");
+    if (res === null || typeof res !== "object" || typeof res.then !== "function") {
+      fail(expectation + " but result was not a thenable");
     }
 
     try {
-      resolve(innerThenable.then(
+      resolve(res.then(
         function () {
-          fail("Expected a " +
-            expectedName +
-            " to be thrown asynchronously but no exception was thrown at all");
+          fail(expectation + " but no exception was thrown at all");
         },
         function (thrown) {
           var actualName;
-          if (typeof thrown !== "object" || thrown === null) {
-            fail("Thrown value was not an object!");
+          if (thrown === null || typeof thrown !== "object") {
+            fail(expectation + " but thrown value was not an object");
           } else if (thrown.constructor !== expectedErrorConstructor) {
             actualName = thrown.constructor.name;
             if (expectedName === actualName) {
-              fail("Expected a " +
-                expectedName +
+              fail(expectation +
                 " but got a different error constructor with the same name");
             }
-            fail("Expected a " + expectedName + " but got a " + actualName);
+            fail(expectation + " but got a " + actualName);
           }
         }
       ));
     } catch (thrown) {
-      fail("Expected a " +
-        expectedName +
-        " to be thrown asynchronously but .then threw synchronously");
+      fail(expectation + " but .then threw synchronously");
     }
   });
 };