improved error msg on toBeRehectedWithError and all other built-in async matchers

src/core/matchers/async/toBePending.js

@@ -12,7 +12,9 @@ getJasmineRequireObj().toBePending = function(j$) {
     return {
       compare: function(actual) {
         if (!j$.isPromiseLike(actual)) {
-          throw new Error('Expected toBePending to be called on a promise.');
+          throw new Error(
+            `Expected toBePending to be called on a promise but was on a ${typeof actual}.`
+          );
         }
         const want = {};
         return Promise.race([actual, Promise.resolve(want)]).then(

src/core/matchers/async/toBeRejected.js

@@ -14,7 +14,9 @@ getJasmineRequireObj().toBeRejected = function(j$) {
     return {
       compare: function(actual) {
         if (!j$.isPromiseLike(actual)) {
-          throw new Error('Expected toBeRejected to be called on a promise.');
+          throw new Error(
+            `Expected toBeRejected to be called on a promise but was on a ${typeof actual}.`
+          );
         }
         return actual.then(
           function() {

src/core/matchers/async/toBeRejectedWith.js

@@ -16,7 +16,7 @@ getJasmineRequireObj().toBeRejectedWith = function(j$) {
       compare: function(actualPromise, expectedValue) {
         if (!j$.isPromiseLike(actualPromise)) {
           throw new Error(
-            'Expected toBeRejectedWith to be called on a promise.'
+            `Expected toBeRejectedWith to be called on a promise but was on a ${typeof actualPromise}.`
           );
         }
 

src/core/matchers/async/toBeRejectedWithError.js

@@ -19,7 +19,7 @@ getJasmineRequireObj().toBeRejectedWithError = function(j$) {
       compare: function(actualPromise, arg1, arg2) {
         if (!j$.isPromiseLike(actualPromise)) {
           throw new Error(
-            'Expected toBeRejectedWithError to be called on a promise.'
+            `Expected toBeRejectedWithError to be called on a promise but was on a ${typeof actualPromise}.`
           );
         }
 

src/core/matchers/async/toBeResolved.js

@@ -14,7 +14,9 @@ getJasmineRequireObj().toBeResolved = function(j$) {
     return {
       compare: function(actual) {
         if (!j$.isPromiseLike(actual)) {
-          throw new Error('Expected toBeResolved to be called on a promise.');
+          throw new Error(
+            `Expected toBeResolved to be called on a promise but was on a ${typeof actual}.`
+          );
         }
 
         return actual.then(

src/core/matchers/async/toBeResolvedTo.js

@@ -15,7 +15,9 @@ getJasmineRequireObj().toBeResolvedTo = function(j$) {
     return {
       compare: function(actualPromise, expectedValue) {
         if (!j$.isPromiseLike(actualPromise)) {
-          throw new Error('Expected toBeResolvedTo to be called on a promise.');
+          throw new Error(
+            `Expected toBeResolvedTo to be called on a promise but was on a ${typeof actualPromise}.`
+          );
         }
 
         function prefix(passed) {