TestStateCommand always gives me InvalidDefinition

[bmariusrazvan26]

HI all, was wondering if someone could maybe shed some light into this issue that I'm having (if I'm doing something wrong, or if it's an actual issue). I've been trying to use on the new v3 version, with no avail, the newly added TestStateCommand option in order to validate my state machine definition prior to running/updating it, however no matter what I tried, I always get upon running the command, InvalidDefinition. I tried everything, even a plain simple state machine and I get the same results.

Below are some snippets of my code and the response that I get every time:

export interface TestStepFunctionDefinition {
    definition: string,
    roleArn: string,
    input: string,
    inspectionLevel: InspectionLevel,
    revealSecrets: boolean
}

export const handler: APIGatewayProxyHandler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> =>
    executeWithErrorHandling(async () => {
        const requestBody: TestStepFunctionDefinition = JSON.parse(
            event.body || '{}'
        );

        const command = new TestStateCommand(requestBody);
        const response = await stepFunctionFactory().send(command);

        return {
            statusCode: 200,
            body: JSON.stringify(response),
        };
    });

A sample request for the above:

{
    "roleArn": "arn:aws:states:us-east-1:671092559308:stateMachine:myStateMachine",
    "definition": "{\"Comment\":\"A description of my state machine\",\"StartAt\":\"Lambda Invoke\",\"States\":{\"Lambda Invoke\":{\"Type\":\"Task\",\"Resource\":\"arn:aws:states:::lambda:invoke\",\"OutputPath\":\"$.Payload\",\"Parameters\":{\"Payload.$\":\"$\",\"FunctionName\":\"arn:aws:lambda:us-east-1:671092559308:function:test-state-function:$LATEST\"},\"Retry\":[{\"ErrorEquals\":[\"Lambda.ServiceException\",\"Lambda.AWSLambdaException\",\"Lambda.SdkClientException\",\"Lambda.TooManyRequestsException\"],\"IntervalSeconds\":1,\"MaxAttempts\":3,\"BackoffRate\":2}],\"End\":true}}}"
}

Whatever I put into the definition field, regardless if it is a plain simple start-end state machine, I always get this error:

ERROR	Lambda Error: InvalidDefinition: Missing required field: 'Type'
    at de_InvalidDefinitionRes (/var/task/node_modules/@aws-sdk/client-sfn/dist-cjs/index.js:2962:21)
    at de_TestStateCommandError (/var/task/node_modules/@aws-sdk/client-sfn/dist-cjs/index.js:2686:19)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async /var/task/node_modules/@smithy/middleware-serde/dist-cjs/index.js:35:20
    at async /var/task/node_modules/@aws-sdk/middleware-signing/dist-cjs/index.js:184:18
    at async /var/task/node_modules/@smithy/middleware-retry/dist-cjs/index.js:320:38
    at async /var/task/node_modules/@aws-sdk/middleware-logger/dist-cjs/index.js:33:22 {
  '$fault': 'client',
  '$metadata': {
    httpStatusCode: 400,
    requestId: '79ad0c65-6b8d-4a3c-9efb-46ecebce8bfb',
    extendedRequestId: undefined,
    cfId: undefined,
    attempts: 1,
    totalRetryDelay: 0
  },
  __type: 'com.amazonaws.swf.service.v2.model#InvalidDefinition'
}

With the same request above, if I try ,for instance, the UpdateStateMachineCommand, it works just fine.

Thank you!