test_hello_world.rs

use asl::asl::execution::{
    Execution, ExecutionStatus, StateExecutionHandler, StateExecutionOutput,
};
use asl::asl::state_machine::StateMachine;
use asl::asl::types::execution::EmptyContext;
use rstest::rstest;
use serde_json::{json, Value};
use similar_asserts::assert_eq;

struct TaskHandler {}
impl StateExecutionHandler for TaskHandler {
    type TaskExecutionError = String;

    fn execute_task(
        &self,
        resource: &str,
        input: &Value,
        credentials: Option<&Value>,
    ) -> Result<Option<Value>, Self::TaskExecutionError> {
        let result = match resource {
            "SayHello" => "Hello",
            "SayWorld" => "World",
            _ => Err("Unknown resource!")?,
        };
        println!("{}", result);
        Ok(None) // We opt into returning nothing
    }
}

#[rstest]
fn execute_hello_world() {
    let definition = r#"{
      "Comment": "A simple minimal example of the States language",
      "StartAt": "State: Hello",
      "States": {
        "State: Hello": {
          "Type": "Task",
          "Resource": "SayHello",
          "Next": "State: World"
        },
        "State: World": {
          "Type": "Task",
          "Resource": "SayWorld",
          "End": true
        }
      }
    }"#;
    let state_machine = StateMachine::parse(definition).unwrap();
    let input = Value::Null;
    let execution: Execution<TaskHandler, EmptyContext> =
        state_machine.start(&input, TaskHandler {}, EmptyContext {});
    // the Execution type implements Iterator, so we can iterate until there are no more states to execute
    let steps: Vec<StateExecutionOutput> = execution.collect();
    assert_eq!(
        steps[0],
        StateExecutionOutput {
            status: ExecutionStatus::Executing,
            state_name: Some("State: Hello".to_string()),
            result: Some(json!({})), // returning nothing is the same as returning an empty JSON object
        }
    );
    //
    assert_eq!(
        steps[1],
        StateExecutionOutput {
            status: ExecutionStatus::FinishedWithSuccess(Some(json!({}))),
            state_name: Some("State: World".to_string()),
            result: Some(json!({})),
        }
    );
}