How to write angular unit test for function and switch case

Question

extractValue(exemptionLevel: string, exemptionValue: any): string {
switch(exemptionLevel) {
  case "C": return exemptionValue.isoCountryCode.toString();
  case "R": return exemptionValue.districtNumber.toString();
  case "D": return exemptionValue.divisionCode.toString();
  case "T": return exemptionValue.terminalNumber.toString();
}

}

i tried below

it('expected value extractValue() c', () => {
component.extractValue('C','isoCountry');
expect('C').toEqual('isoCountry')

// expect(component.extractValue(expectedLevel[0], exemptionValue.isoCountryCode)).toHaveBeenCalled();

});

it showing error TypeError: Cannot read property 'toString' of undefined

Answer 1

You are sending a string parameter to the function and you are expecting to access its isoCountryCode property, which will always be undefined. You have to provide the tested function with exemptionValue mock.

it('expected value extractValue() c', () => {
  const isoCountryMockResult = 'someResult';
  const exemptionValue = { isoCountryCode: isoCountryMockResult } // define your mock
  component.extractValue('C', exemptionValue);
  expect('C').toEqual(isoCountryMockResult)
}

This should work, but you have to adjust it to your needs