Add comments to tests for generic version of jasmine.objectContaining

jasmine/index.d.ts

@@ -24,9 +24,9 @@ declare function afterEach(action: (done: DoneFn) => void, timeout?: number): vo
 declare function beforeAll(action: (done: DoneFn) => void, timeout?: number): void;
 declare function afterAll(action: (done: DoneFn) => void, timeout?: number): void;
 
+declare function expect(spy: Function): jasmine.Matchers<any>;
 declare function expect<T extends ArrayLike<T>>(actual: ArrayLike<T>): jasmine.ArrayLikeMatchers<T>;
 declare function expect<T>(actual: T): jasmine.Matchers<T>;
-declare function expect(spy: Function): jasmine.Matchers<any>;
 
 declare function fail(e?: any): void;
 /** Action method that should be called when the async work is complete */

jasmine/jasmine-tests.ts

@@ -679,12 +679,19 @@ describe("jasmine.objectContaining", () => {
     });
 
     it("matches objects with the expect key/value pairs", () => {
-        expect(foo).toEqual(jasmine.objectContaining<fooType>({
-            bar: ''
+        // not explictly providing the type on objectContaining only guards against
+        // missmatching types on know properties
+        expect(foo).not.toEqual(jasmine.objectContaining({
+            a: 37,
+            foo: 2, // <-- this does not cause an error as the compiler cannot infer the type completely
+            // b: '123', <-- this would cause an error as `b` defined as number in fooType
         }));
 
-        expect(foo).not.toEqual(jasmine.objectContaining({
-            a: 37
+        // explictly providing the type on objectContaining makes the guard more precise
+        // as misspelled properties are detected as well
+        expect(foo).not.toEqual(jasmine.objectContaining<fooType>({
+            bar: '',
+            // foo: 1, <-- this would cause an error as `foo` is not defined in fooType
         }));
     });