isCaseValid() {
        if (this.currentGroup >= this.data.groups.length || this.currentGroup < 0) return false;
        const caseCount = this.testData.groups[this.currentGroup].inputs[0].values.length;
        if (this.currentCase >= caseCount || this.currentCase < 0) return false;

        return true;
    }
Checks whether given case-group pair exists in the test