Manual mocks for aws-sdk.js using jest.

aws-sdk.ts

// inspired by: https://derikwhittaker.blog/2018/02/20/using-manual-mocks-to-test-the-aws-sdk-with-jest/

let AWS = {
    // This here is to allow/prevent runtime errors if you are using
    //   AWS.config to do some runtime configuration of the library.
    // If you do not need any runtime configuration you can omit this.
    config: {
        setPromisesDependency: (arg) => {},
        update: (arg) => {},
    },
    Kinesis: function() {

    },
    STS: function() {

    },
    Lambda: function() {

    },
    DynamoDB: {
        DocumentClient: function (params) {
        }
    },
    CloudWatch: function() {

    },
    VERSION: "2.264.1",
};

// Because I care about using the S3 service's which are part of the SDK
//  I need to setup the correct identifier.
//
AWS.Kinesis.prototype = {
    ...AWS.Kinesis.prototype,

    // Stub for the putRecord method in the sdk
    putRecord(params, callback) {
        callback(null);
    },
    createStream(params, callback) {
        // console.log("create stream mock");
        callback(null);
    },
    deleteStream(params, callback) {
        // console.log("delete stream mock");
        callback(null);
    },
    waitFor(state, params, callback) {
        // console.log("wait for mock");
        callback(null);
    },
    describeStream(params, callback) {
        // console.log("describeStream mock");
        callback(null, {
            "StreamDescription": {
                "KeyId": null,
                "EncryptionType": "NONE",
                "StreamStatus": "ACTIVE",
                "StreamName": "process_order_mssql_local",
                "Shards": [{
                    "ShardId": "shardId-000000000000",
                    "HashKeyRange": {
                        "EndingHashKey": "340282366920938463463374607431768211455",
                        "StartingHashKey": "0"
                    },
                    "SequenceNumberRange": {
                        "StartingSequenceNumber": "49585023131013678200177316516963950164506062627784359938"
                    }
                }],
                "StreamARN": "arn:aws:kinesis:us-east-1:xxxxxxxxxxx:stream/xxxxxx",
                "EnhancedMonitoring": [{
                    "ShardLevelMetrics": []
                }],
                "StreamCreationTimestamp": 1527880065.0,
                "RetentionPeriodHours": 24
            }
        });
    }
};

AWS.Lambda.prototype = {
    ...AWS.Lambda.prototype,
    createEventSourceMapping(params, callback) {
        // console.log("createEventSourceMapping mock");
        callback(null, {"UUID": "exampleFakeUUID"});
    },
    updateEventSourceMapping(params, callback) {
        callback(null);
    },
    deleteEventSourceMapping(params, callback) {
        callback(null);
    }
};

AWS.DynamoDB.DocumentClient.prototype = {
    ...AWS.DynamoDB.DocumentClient.prototype,
    update(params, callback) {
        // console.log("Dynamo DocumentClient updateItem mock")
        callback(null);
    },
    get(params, callback) {
        // console.log("Dynamo DocumentClient get mock")
        /*
         https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#get-property
        */
        if (params.Key.merchant_id === 800) {
            callback(null, {"Item": {"is_active": true}});
        } else {
            callback(null);  // FIXME: is this proper? what does kinesis return for get if nothing found?
        }
    }
};

AWS.CloudWatch.prototype = {
    ...AWS.CloudWatch.prototype,
    putMetricAlarm(params = {}, callback) {
        callback(null);
    },
    deleteAlarms(params = {}, callback) {
        callback(null);
    },
};

// Export my AWS function so it can be referenced via requires
module.exports = AWS;