dpk.test.js

const { deterministicPartitionKey } = require("./dpk");

// naive hash check
const isHash = (string) => string.length === 128;

const testEvent = {
  partitionKey: 123,
}

describe("deterministicPartitionKey", () => {
  it("Returns the literal '0' when given no input", () => {
    const trivialKey = deterministicPartitionKey();
    expect(trivialKey).toBe("0");
  });

  it(`Returns the literal '${testEvent.partitionKey}' when given the integer ${testEvent.partitionKey}`, () => {
    const key = deterministicPartitionKey(testEvent);
    expect(key).toBe(`${testEvent.partitionKey}`);
  });

  it(`Returns the literal '${testEvent.partitionKey}' when given the string '123'`, () => {
    const stringTestEvent = {
      partitionKey: '123'
    }

    const key = deterministicPartitionKey(stringTestEvent);
    expect(key).toBe(stringTestEvent.partitionKey);
  });

  it(`Returns the literal '823' when given the string '823'`, () => {
    const stringTestEvent = {
      partitionKey: '823'
    }

    const key = deterministicPartitionKey(stringTestEvent);
    expect(key).toBe(stringTestEvent.partitionKey);
  });

  it(`Returns hashedKey when given an event without a partition key`, () => {
    const eventWithoutParitionKey = {}

    const hashedKey = deterministicPartitionKey(eventWithoutParitionKey);

    expect(isHash(hashedKey)).toBe(true);
  });

  it(`Returns hashedKey when given an event without a partition key`, () => {

    const eventWithLongPartitionKey = {
      partitionKey: 'adfads234a'.repeat(400)
    }

    const hashedKey = deterministicPartitionKey(eventWithLongPartitionKey);

    expect(isHash(hashedKey)).toBe(true);
  });
});