Add basic mock provider (#58)

packages/api-provider/src/mock/index.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { ProviderInterface } from '../types';
+
+const mocks = require('./mocks');
+const send = require('./send');
+const state = require('./state');
+const subscribe = require('./subscribe');
+const unsubscribe = require('./unsubscribe');
+
+module.exports = function mockProvider (): ProviderInterface {
+  const self = state();
+
+  mocks(self);
+
+  return {
+    isConnected: (): boolean =>
+      true,
+    send: (method: string, params: Array<mixed>): Promise<mixed> =>
+      send(self, method, params),
+    subscribe: (method: string, ...params: Array<mixed>): Promise<number> =>
+      subscribe(self, method, params),
+    unsubscribe: (id: number): Promise<boolean> =>
+      unsubscribe(self, id)
+  };
+};

packages/api-provider/src/mock/mocks.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { MockState, MockState$Subscription$Callback } from './types';
+
+module.exports = function mocks ({ subscriptions }: MockState): void {
+  let blockNumber = 0;
+
+  const updateSubs = (method, value) => {
+    subscriptions[method].lastValue = value;
+
+    Object
+      .values(subscriptions[method].callbacks)
+      .forEach((cb) => {
+        try {
+          // flowlint-next-line unclear-type:off
+          ((cb: any): MockState$Subscription$Callback)(null, value);
+        } catch (error) {
+          console.error(`Error on '${method}' subscription`, error);
+        }
+      });
+  };
+
+  setInterval(() => {
+    updateSubs('extra_getBlockNumber', `0x${(++blockNumber).toString(16)}`);
+  }, 5000);
+
+  setInterval(() => {
+    updateSubs('extra_getClientTime', `0x${Date.now().toString(16)}`);
+  }, 1000);
+};

packages/api-provider/src/mock/send.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { MockState } from './types';
+
+module.exports = async function send (self: MockState, method: string, params: Array<mixed>): Promise<mixed> {
+  throw new Error('provider.send not implemented');
+};

packages/api-provider/src/mock/state.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { MockState } from './types';
+
+const interfaces = require('@polkadot/api-jsonrpc');
+const l = require('@polkadot/util/logger')('api-mock');
+
+const METHODS = Array.prototype.concat.apply(
+  [], Object.keys(interfaces).map((section) => {
+    return Object
+      .keys(interfaces[section].methods)
+      .map((method) => `${section}_${method}`);
+  })
+);
+
+module.exports = function state (): MockState {
+  const subscriptions = METHODS.reduce((subscriptions, name) => {
+    subscriptions[name] = {
+      callbacks: {},
+      lastValue: null
+    };
+
+    return subscriptions;
+  }, {});
+
+  return {
+    l,
+    subscriptionId: 0,
+    subscriptionMap: {},
+    subscriptions
+  };
+};

packages/api-provider/src/mock/state.spec.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const createState = require('./state');
+
+describe('state', () => {
+  let state;
+
+  beforeEach(() => {
+    state = createState();
+  });
+
+  it('generates a sane initial state', () => {
+    expect(
+      state
+    ).toMatchObject({
+      subscriptionId: 0,
+      subscriptionMap: {}
+    });
+  });
+
+  it('generates a proper section_method map', () => {
+    expect(
+      state.subscriptions
+    ).toMatchObject({
+      'extra_getBlockNumber': {
+        callbacks: {},
+        lastValue: null
+      }
+    });
+  });
+});

packages/api-provider/src/mock/subscribe.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { MockState, MockState$Subscription$Callback } from './types';
+
+module.exports = async function subscribe (self: MockState, method: string, params: Array<mixed>): Promise<number> {
+  self.l.debug(() => ['subscribe', method, params]);
+
+  if (self.subscriptions[method]) {
+    // flowlint-next-line unclear-type:off
+    const callback = ((params.pop(): any): MockState$Subscription$Callback);
+    const id = ++self.subscriptionId;
+
+    self.subscriptions[method].callbacks[id] = callback;
+    self.subscriptionMap[id] = method;
+
+    callback(null, self.subscriptions[method].lastValue);
+
+    return id;
+  }
+
+  throw new Error(`provider.subscribe: Invalid method '${method}'`);
+};

packages/api-provider/src/mock/subscribe.spec.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const createState = require('./state');
+const subscribe = require('./subscribe');
+
+describe('subscribe', () => {
+  let state;
+
+  beforeEach(() => {
+    state = createState();
+  });
+
+  it('fails on unknown methods', () => {
+    return subscribe(state, 'test_notFound').catch((error) => {
+      expect(error.message).toMatch(/Invalid method 'test_notFound'/);
+    });
+  });
+
+  it('returns a subscription id', () => {
+    return subscribe(state, 'extra_getBlockNumber', [() => void 0]).then((id) => {
+      expect(id).toEqual(state.subscriptionId);
+    });
+  });
+
+  it('stores the mapping values', () => {
+    const cb = () => void 0;
+
+    return subscribe(state, 'extra_getBlockNumber', [cb]).then((id) => {
+      expect(state.subscriptionMap[id]).toEqual('extra_getBlockNumber');
+      expect(state.subscriptions['extra_getBlockNumber'].callbacks[id]).toEqual(cb);
+    });
+  });
+
+  it('calls back with the last known value', (done) => {
+    state.subscriptions['extra_getBlockNumber'].lastValue = 'testValue';
+
+    subscribe(state, 'extra_getBlockNumber', [(_, value) => {
+      expect(value).toEqual('testValue');
+      done();
+    }]);
+  });
+});

packages/api-provider/src/mock/types.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { Logger } from '@polkadot/util/types';
+
+export type MockState$Subscription$Callback = (error: ?Error, value: mixed) => void;
+
+export type MockState$Subscriptions = {
+  [string]: {
+    callbacks: {
+      [number]: MockState$Subscription$Callback
+    },
+    lastValue: mixed
+  }
+};
+
+export type MockState = {
+  l: Logger,
+  subscriptionId: number,
+  subscriptionMap: {
+    [number]: string
+  },
+  subscriptions: MockState$Subscriptions
+};

packages/api-provider/src/mock/unsubscribe.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type { MockState } from './types';
+
+module.exports = async function subscribe (self: MockState, id: number): Promise<boolean> {
+  const method = self.subscriptionMap[id];
+
+  self.l.debug(() => ['unsubscribe', id, method]);
+
+  if (!method) {
+    throw new Error(`Unable to find subscription for ${id}`);
+  }
+
+  delete self.subscriptionMap[id];
+  delete self.subscriptions[method].callbacks[id];
+
+  return true;
+};

packages/api-provider/src/mock/unsubscribe.spec.js

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+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+
+const createState = require('./state');
+const subscribe = require('./subscribe');
+const unsubscribe = require('./unsubscribe');
+
+describe('unsubscribe', () => {
+  let state;
+  let id;
+
+  beforeEach(() => {
+    state = createState();
+
+    return subscribe(state, 'extra_getBlockNumber', [() => void 0]).then((_id) => {
+      id = _id;
+    });
+  });
+
+  it('fails on unknown ids', () => {
+    return unsubscribe(state, 5).catch((error) => {
+      expect(error.message).toMatch(/Unable to find/);
+    });
+  });
+
+  it('unsubscribes successfully', () => {
+    return unsubscribe(state, id);
+  });
+
+  it('fails on double unsubscribe', () => {
+    return unsubscribe(state, id)
+      .then(() => unsubscribe(state, id))
+      .catch((error) => {
+        expect(error.message).toMatch(/Unable to find/);
+      });
+  });
+
+  it('clears the subscriptions', () => {
+    return unsubscribe(state, id).then(() => {
+      expect(state.subscriptionMap[id]).not.toBeDefined();
+      expect(state.subscriptions['extra_getBlockNumber'].callbacks[id]).not.toBeDefined();
+    });
+  });
+});