diff --git a/packages/common/http/testing/src/backend.ts b/packages/common/http/testing/src/backend.ts
index b157027e4fb0a..06fb2d8305d5a 100644
--- a/packages/common/http/testing/src/backend.ts
+++ b/packages/common/http/testing/src/backend.ts
@@ -95,13 +95,7 @@ export class HttpClientTestingBackend implements HttpBackend, HttpTestingControl
       let message = `Expected one matching request for criteria "${description}", found none.`;
       if (this.open.length > 0) {
         // Show the methods and URLs of open requests in the error, for convenience.
-        const requests = this.open
-                             .map(testReq => {
-                               const url = testReq.request.urlWithParams;
-                               const method = testReq.request.method;
-                               return `${method} ${url}`;
-                             })
-                             .join(', ');
+        const requests = this.open.map(describeRequest).join(', ');
         message += ` Requests received are: ${requests}.`;
       }
       throw new Error(message);
@@ -135,12 +129,7 @@ export class HttpClientTestingBackend implements HttpBackend, HttpTestingControl
     }
     if (open.length > 0) {
       // Show the methods and URLs of open requests in the error, for convenience.
-      const requests = open.map(testReq => {
-                             const url = testReq.request.urlWithParams.split('?')[0];
-                             const method = testReq.request.method;
-                             return `${method} ${url}`;
-                           })
-                           .join(', ');
+      const requests = open.map(describeRequest).join(', ');
       throw new Error(`Expected no open requests, found ${open.length}: ${requests}`);
     }
   }
@@ -158,3 +147,9 @@ export class HttpClientTestingBackend implements HttpBackend, HttpTestingControl
     }
   }
 }
+
+function describeRequest(testRequest: TestRequest): string {
+  const url = testRequest.request.urlWithParams;
+  const method = testRequest.request.method;
+  return `${method} ${url}`;
+}
diff --git a/packages/common/http/testing/test/request_spec.ts b/packages/common/http/testing/test/request_spec.ts
index 4c468297bd2f6..3c6b3f0c4f033 100644
--- a/packages/common/http/testing/test/request_spec.ts
+++ b/packages/common/http/testing/test/request_spec.ts
@@ -91,4 +91,22 @@ describe('HttpClient TestRequest', () => {
               ' Requests received are: GET /some-other-url?query=world, POST /and-another-url.');
     }
   });
+
+  it('throws if there are open requests when verify is called', () => {
+    const mock = new HttpClientTestingBackend();
+    const client = new HttpClient(mock);
+
+    client.get('/some-other-url?query=world').subscribe();
+    client.post('/and-another-url', {}).subscribe();
+
+    try {
+      mock.verify();
+      fail();
+    } catch (error) {
+      expect(error.message)
+          .toBe(
+              'Expected no open requests, found 2:' +
+              ' GET /some-other-url?query=world, POST /and-another-url');
+    }
+  });
 });