metamask-extension/app/scripts/controllers/network/provider-api-tests/block-hash-in-response.ts

/* eslint-disable jest/require-top-level-describe, jest/no-export */

import {
  ProviderType,
  withMockedCommunications,
  withNetworkClient,
} from './helpers';

type TestsForRpcMethodThatCheckForBlockHashInResponseOptions = {
  providerType: ProviderType;
  numberOfParameters: number;
};

/**
 * Defines tests which exercise the behavior exhibited by an RPC method that
 * use `blockHash` in the response data to determine whether the response is
 * cacheable.
 *
 * @param method - The name of the RPC method under test.
 * @param additionalArgs - Additional arguments.
 * @param additionalArgs.numberOfParameters - The number of parameters supported
 * by the method under test.
 * @param additionalArgs.providerType - The type of provider being tested;
 * either `infura` or `custom` (default: "infura").
 */
export function testsForRpcMethodsThatCheckForBlockHashInResponse(
  method: string,
  {
    numberOfParameters,
    providerType,
  }: TestsForRpcMethodThatCheckForBlockHashInResponseOptions,
) {
  if (providerType !== 'infura' && providerType !== 'custom') {
    throw new Error(
      `providerType must be either "infura" or "custom", was "${providerType}" instead`,
    );
  }

  it('does not hit the RPC endpoint more than once for identical requests and it has a valid blockHash', async () => {
    const requests = [{ method }, { method }];
    const mockResult = { blockHash: '0x1' };

    await withMockedCommunications({ providerType }, async (comms) => {
      // The first time a block-cacheable request is made, the latest block
      // number is retrieved through the block tracker first. It doesn't
      // matter what this is — it's just used as a cache key.
      comms.mockNextBlockTrackerRequest();
      comms.mockRpcCall({
        request: requests[0],
        response: { result: mockResult },
      });

      const results = await withNetworkClient(
        { providerType },
        ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
      );

      expect(results).toStrictEqual([mockResult, mockResult]);
    });
  });

  it('hits the RPC endpoint and does not reuse the result of a previous request if the latest block number was updated since', async () => {
    const requests = [{ method }, { method }];
    const mockResults = [{ blockHash: '0x100' }, { blockHash: '0x200' }];

    await withMockedCommunications({ providerType }, async (comms) => {
      // Note that we have to mock these requests in a specific order. The
      // first block tracker request occurs because of the first RPC
      // request. The second block tracker request, however, does not occur
      // because of the second RPC request, but rather because we call
      // `clock.runAll()` below.
      comms.mockNextBlockTrackerRequest({ blockNumber: '0x1' });
      comms.mockRpcCall({
        request: requests[0],
        response: { result: mockResults[0] },
      });
      comms.mockNextBlockTrackerRequest({ blockNumber: '0x2' });
      comms.mockRpcCall({
        request: requests[1],
        response: { result: mockResults[1] },
      });

      const results = await withNetworkClient(
        { providerType },
        async (client) => {
          const firstResult = await client.makeRpcCall(requests[0]);
          // Proceed to the next iteration of the block tracker so that a new
          // block is fetched and the current block is updated.
          client.clock.runAll();
          const secondResult = await client.makeRpcCall(requests[1]);
          return [firstResult, secondResult];
        },
      );

      expect(results).toStrictEqual(mockResults);
    });
  });

  it('does not reuse the result of a previous request if result.blockHash was null', async () => {
    const requests = [{ method }, { method }];
    const mockResults = [
      { blockHash: null, extra: 'some value' },
      { blockHash: '0x100', extra: 'some other value' },
    ];

    await withMockedCommunications({ providerType }, async (comms) => {
      // The first time a block-cacheable request is made, the latest block
      // number is retrieved through the block tracker first. It doesn't
      // matter what this is — it's just used as a cache key.
      comms.mockNextBlockTrackerRequest();
      comms.mockRpcCall({
        request: requests[0],
        response: { result: mockResults[0] },
      });
      comms.mockRpcCall({
        request: requests[1],
        response: { result: mockResults[1] },
      });

      const results = await withNetworkClient(
        { providerType },
        ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
      );

      expect(results).toStrictEqual(mockResults);
    });
  });

  it('does not reuse the result of a previous request if result.blockHash was undefined', async () => {
    const requests = [{ method }, { method }];
    const mockResults = [
      { extra: 'some value' },
      { blockHash: '0x100', extra: 'some other value' },
    ];

    await withMockedCommunications({ providerType }, async (comms) => {
      // The first time a block-cacheable request is made, the latest block
      // number is retrieved through the block tracker first. It doesn't
      // matter what this is — it's just used as a cache key.
      comms.mockNextBlockTrackerRequest();
      comms.mockRpcCall({
        request: requests[0],
        response: { result: mockResults[0] },
      });
      comms.mockRpcCall({
        request: requests[1],
        response: { result: mockResults[1] },
      });

      const results = await withNetworkClient(
        { providerType },
        ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
      );

      expect(results).toStrictEqual(mockResults);
    });
  });

  it('does not reuse the result of a previous request if result.blockHash was "0x0000000000000000000000000000000000000000000000000000000000000000"', async () => {
    const requests = [{ method }, { method }];
    const mockResults = [
      {
        blockHash:
          '0x0000000000000000000000000000000000000000000000000000000000000000',
        extra: 'some value',
      },
      { blockHash: '0x100', extra: 'some other value' },
    ];

    await withMockedCommunications({ providerType }, async (comms) => {
      // The first time a block-cacheable request is made, the latest block
      // number is retrieved through the block tracker first. It doesn't
      // matter what this is — it's just used as a cache key.
      comms.mockNextBlockTrackerRequest();
      comms.mockRpcCall({
        request: requests[0],
        response: { result: mockResults[0] },
      });
      comms.mockRpcCall({
        request: requests[1],
        response: { result: mockResults[1] },
      });

      const results = await withNetworkClient(
        { providerType },
        ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
      );

      expect(results).toStrictEqual(mockResults);
    });
  });

  for (const emptyValue of [null, undefined, '\u003cnil\u003e']) {
    it(`does not retry an empty response of "${emptyValue}"`, async () => {
      const request = { method };
      const mockResult = emptyValue;

      await withMockedCommunications({ providerType }, async (comms) => {
        // The first time a block-cacheable request is made, the latest block
        // number is retrieved through the block tracker first. It doesn't
        // matter what this is — it's just used as a cache key.
        comms.mockNextBlockTrackerRequest();
        comms.mockRpcCall({
          request,
          response: { result: mockResult },
        });

        const result = await withNetworkClient(
          { providerType },
          ({ makeRpcCall }) => makeRpcCall(request),
        );

        expect(result).toStrictEqual(mockResult);
      });
    });

    it(`does not reuse the result of a previous request if it was "${emptyValue}"`, async () => {
      const requests = [{ method }, { method }];
      const mockResults = [emptyValue, { blockHash: '0x100' }];

      await withMockedCommunications({ providerType }, async (comms) => {
        // The first time a block-cacheable request is made, the latest block
        // number is retrieved through the block tracker first. It doesn't
        // matter what this is — it's just used as a cache key.
        comms.mockNextBlockTrackerRequest();
        comms.mockRpcCall({
          request: requests[0],
          response: { result: mockResults[0] },
        });
        comms.mockRpcCall({
          request: requests[1],
          response: { result: mockResults[1] },
        });

        const results = await withNetworkClient(
          { providerType },
          ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
        );

        expect(results).toStrictEqual(mockResults);
      });
    });
  }

  for (const paramIndex of [...Array(numberOfParameters).keys()]) {
    it(`does not reuse the result of a previous request with a valid blockHash if parameter at index "${paramIndex}" differs`, async () => {
      const firstMockParams = [
        ...new Array(numberOfParameters).fill('some value'),
      ];
      const secondMockParams = firstMockParams.slice();
      secondMockParams[paramIndex] = 'another value';
      const requests = [
        {
          method,
          params: firstMockParams,
        },
        { method, params: secondMockParams },
      ];
      const mockResults = [{ blockHash: '0x100' }, { blockHash: '0x200' }];

      await withMockedCommunications({ providerType }, async (comms) => {
        // The first time a block-cacheable request is made, the latest block
        // number is retrieved through the block tracker first. It doesn't
        // matter what this is — it's just used as a cache key.
        comms.mockNextBlockTrackerRequest();
        comms.mockRpcCall({
          request: requests[0],
          response: { result: mockResults[0] },
        });
        comms.mockRpcCall({
          request: requests[1],
          response: { result: mockResults[1] },
        });

        const results = await withNetworkClient(
          { providerType },
          ({ makeRpcCallsInSeries }) => makeRpcCallsInSeries(requests),
        );

        expect(results).toStrictEqual([mockResults[0], mockResults[1]]);
      });
    });
  }
}