title: Karma Test failing , with TypeError "...." is not a fuction
body: <p>I am getting error while doing Angular testing, the error is</p>
  <blockquote>
  <p>TypeError: this.numberPipe.transform is not a function</p>
  </blockquote>
  <p>In ts I have this
  we are actually making primaryPhone.type.value to a string using below</p>
  <pre><code>export class PhoneNumberPipe implements PipeTransform {
    transform(value: string): any {
      let formattedNumber;
      let areaCode: string;
      .....................}
  
  populatePhoneTypeAndEmail(): void {
      this.primaryPhone.type.value = this.personalInfo.primaryPhone.phoneType;
      this.primaryPhone.number.value = this.numberPipe.
        transform(this.personalInfo.primaryPhone.phoneArea.concat(this.personalInfo.primaryPhone.phoneRest));
      this.primaryPhone.extension.value = this.personalInfo.primaryPhone.phoneExtn;
  -----}
  </code></pre>
  <p>In spec</p>
  <pre><code>Providers: [.....{ provide: PhoneNumberPipe, useValue:{ numberPipe: { transform: () =&gt; &quot;a string mocked string&quot; }}}.....]
  </code></pre>
  <p>In Spec I have tried this too</p>
  <pre><code>{ provide: PhoneNumberPipe, useValue:{ numberPipe: () =&gt; &quot;a string mocked string&quot; }},
  </code></pre>