Added assertion for expected state machine output.

src/assertions/index.ts

@@ -6,6 +6,7 @@ import toHaveEventWithSource from "./toHaveEventWithSource";
 import toHaveObjectWithNameEqualTo from "./toHaveObjectWithNameEqualTo";
 import toExistInDynamoTable from "./toExistInDynamoTable";
 import toHaveCompletedExecutionWithStatus from "./toHaveCompletedExecutionWithStatus";
+import toMatchStateMachineOutput from "./toMatchStateMachineOutput";
 
 export default {
   ...toExistAsS3Bucket,
@@ -15,5 +16,6 @@ export default {
   ...toHaveEventWithSource,
   ...toHaveObjectWithNameEqualTo,
   ...toExistInDynamoTable,
-  ...toHaveCompletedExecutionWithStatus
+  ...toHaveCompletedExecutionWithStatus,
+  ...toMatchStateMachineOutput,
 };

src/assertions/toMatchStateMachineOutput/index.ts

@@ -0,0 +1,57 @@
+import { testResult, TestResultOutput } from "utils/testResult";
+import { StepFunctions as AWSStepFunctions } from "aws-sdk";
+
+export default {
+  async toMatchStateMachineOutput(
+    stateMachineName: string,
+    expectedOutput: any
+  ): Promise<TestResultOutput> {
+    const stepFunctions = new AWSStepFunctions();
+    const allStateMachines = await stepFunctions.listStateMachines().promise();
+
+    const smList = allStateMachines.stateMachines.filter(
+      (stateMachine: any) => stateMachine.name === stateMachineName
+    );
+
+    const stateMachineArn = smList[0].stateMachineArn;
+    const listExecParams = { stateMachineArn: stateMachineArn };
+    const executionList = await stepFunctions
+      .listExecutions(listExecParams)
+      .promise();
+
+    const executionResult = await stepFunctions
+      .describeExecution({
+        executionArn: executionList.executions[0].executionArn,
+      })
+      .promise();
+
+    // if (allStateMachines === undefined) {
+    //     throw new Error(
+    //     "The list of state machines is undefined. You might have forgotten to run build()."
+    //     );
+    // }
+
+    if (executionResult.status === "SUCCEEDED") {
+      if (executionResult.output === expectedOutput) {
+        return testResult(
+          `Output is ${JSON.stringify(executionResult.output)} as expected`,
+          true
+        );
+      } else {
+        return testResult(
+          `Expected output was ${JSON.stringify(
+            expectedOutput
+          )}, but output received was ${JSON.stringify(
+            executionResult.output
+          )}`,
+          false
+        );
+      }
+    }
+
+    return testResult(
+      "Step Function execution failed. Cannot verify output for failed executions.",
+      false
+    );
+  },
+};