grafana/public/app/features/explore/PlaceholdersBuffer.test.ts

import PlaceholdersBuffer from './PlaceholdersBuffer';

describe('PlaceholdersBuffer', () => {
  it('does nothing if no placeholders are defined', () => {
    const text = 'metric';
    const buffer = new PlaceholdersBuffer(text);

    expect(buffer.hasPlaceholders()).toBe(false);
    expect(buffer.toString()).toBe(text);
    expect(buffer.getNextMoveOffset()).toBe(0);
  });

  it('respects the traversal order of placeholders', () => {
    const text = 'sum($2 offset $1) by ($3)';
    const buffer = new PlaceholdersBuffer(text);

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('sum( offset ) by ()');
    expect(buffer.getNextMoveOffset()).toBe(12);

    buffer.setNextPlaceholderValue('1h');

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('sum( offset 1h) by ()');
    expect(buffer.getNextMoveOffset()).toBe(-10);

    buffer.setNextPlaceholderValue('metric');

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('sum(metric offset 1h) by ()');
    expect(buffer.getNextMoveOffset()).toBe(16);

    buffer.setNextPlaceholderValue('label');

    expect(buffer.hasPlaceholders()).toBe(false);
    expect(buffer.toString()).toBe('sum(metric offset 1h) by (label)');
    expect(buffer.getNextMoveOffset()).toBe(0);
  });

  it('respects the traversal order of adjacent placeholders', () => {
    const text = '$1$3$2$4';
    const buffer = new PlaceholdersBuffer(text);

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('');
    expect(buffer.getNextMoveOffset()).toBe(0);

    buffer.setNextPlaceholderValue('1');

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('1');
    expect(buffer.getNextMoveOffset()).toBe(0);

    buffer.setNextPlaceholderValue('2');

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('12');
    expect(buffer.getNextMoveOffset()).toBe(-1);

    buffer.setNextPlaceholderValue('3');

    expect(buffer.hasPlaceholders()).toBe(true);
    expect(buffer.toString()).toBe('132');
    expect(buffer.getNextMoveOffset()).toBe(1);

    buffer.setNextPlaceholderValue('4');

    expect(buffer.hasPlaceholders()).toBe(false);
    expect(buffer.toString()).toBe('1324');
    expect(buffer.getNextMoveOffset()).toBe(0);
  });
});