How do I get the Assertion success or fail message through an email in JMeter?

Question

I'm trying to get the Assertion results through an email. There are several endpoints(requests) and associated assertions in my test plan.

Below is the Groovy code I'm using in JSR223 PreProcessor. In My SMTP Sampler, I've been using ${body} to get the results from the script.

But in email prints null when all the Assertions are passing and print exceptions when those are failing.

I need to get below through email.

1. Success message when there are all the assertions are passing
2. Fail message with the failure request name when they

import org.apache.jmeter.assertions.AssertionResult;

AssertionResult[] results = prev.getAssertionResults();
StringBuilder body = new StringBuilder();
for (AssertionResult result : results) {
    body.append(result.getFailureMessage());
    body.append(System.getProperty("line.separator"));
}
vars.put("body", body.toString());

Answer 1

1. JSR223 PreProcessor is being executed before each Sampler in its scope
2. prev stands for previous Sampler Result

Assuming above 2 points it is absolutely expected that when JSR223 PreProcessor is being executed before the first Sampler in your test the previous result doesn't exist yet, you just need to add another condition to check whether it is null or not.

import org.apache.jmeter.assertions.AssertionResult

if (prev != null) { // ensure that we have the previous sampler result
    AssertionResult[] results = prev.getAssertionResults();
    StringBuilder body = new StringBuilder();
    for (AssertionResult result : results) {
        body.append(result.getFailureMessage());
        body.append(System.getProperty("line.separator"));
    }
    vars.put("body", body.toString());
}