How can I write test case for switch statement for given Angular function?

I am trying to write test case for the function below which contains switch case. I am not sure where can I start from. I need help writing test case, to increase my code coverage.

  public getPercentageValue(cols: string, element: any, freq: freq, MarkDisplay: boolean): string {
    const returns = freq === Labels.MONTHLY_freq ? element.returns.Monthly : element.returns.Quarterly;
    const emptyTemplate = `<div class="row-template"><p class="percentage-value-template">&#8211; &#8211;</p></div>`;
    let data: any = {};
    switch (cols) {
      case 'quater':
        data = this.buildTemplate(
          returns.currentYearPerformance.YEAR_TO_DATE_RETURN.Part,
          returns.currentYearPerformance.YEAR_TO_DATE_RETURN.Mark,
        );
        break;
      case 'year':
        data = this.buildTemplate(
          returns.returns.ONE_YEAR_RETURN.Part,
          returns.returns.ONE_YEAR_RETURN.Mark,
        );
        break;
      case 'five-y':
        data = this.buildTemplate(
          returns.returns.FIVE_YEARS_RETURN.Part,
          returns.returns.FIVE_YEARS_RETURN.Mark,
        );
        break;

      default:
        break;
    }

    const showAmountMark = MarkDisplay
      ? `<span>${
          data.amountMark && data.amountMark !== 'N/A' ? data.amountMark : emptyTemplate
        }</span>`
      : '';

    return `
        <div class="row-template">
          <p class="percentage-value-template">${
            data.mark && data.mark !== 'N/A' ? data.mark : emptyTemplate
          }</p>
          <p class="template-subtitle">&nbsp;</p>
          <p class="percentage-value-template">${showAmountMark}</p>
          <p class="template-subtitle">&nbsp;</p>
        </div>
      `;
  }