How to test pipes in angular

I have a scenerio where a pipe return the class name based on the input and my test case is getting failed if I trying to test the pipe. My implementation is as follows, can anyone pls help.Thanks.
I have a html as follows,

   <div [class]="type | functionTester: getNameOfClass: this"> 


   type = 'high';
      getNameOfClass() {
       if (type === 'high') {
         return 'HIGH';
       } else {
         return 'LOW';


   export class functionTesterPipe implements PipeTransform {
    public transform(
       value: any,
       handler: (value: any) => any,
       context?: any
      ): any {
       if (context) {
        return, value);

         return handler(value);


 const { find } = await shallow
      bind: { chartData: chartData, type: 'ORG_BENCHMARK' }
  const pipe = new functionTesterPipe();
  expect(pipe.transform('high', instance.prepareClassName)).toBe('High');
  expect(find('.High').length).toBe(1); -> Failing at this line as [expect 0 to be 1]


I have a scenerio where a pipe return the class name based on the input and my test case is getting failed if I trying to test the pipe. My implementation is as follows, can anyone pls help.Thanks.

139 thoughts on “How to test pipes in angular”

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