Expected exception but no exception was thrown but standard error shows expected exception

[amimas]

I'm not able to find an issue similar to this here or anywhere else. So, I can't tell if it's a bug or not. However, I have a very simple test case that is failing and I'm not able to find the root cause. I'd appreciate if you can help.

Issue description

I have a Java class that will parse a given JSON string. The method that parses the string will throw NullPointerException if expected JSON entry is not found. I added a Groovy Spock test to validate this.

The test case is failing with following error message:

Expected exception of type 'java.lang.NullPointerException', but no exception was thrown
        at org.spockframework.lang.SpecInternals.checkExceptionThrown(SpecInternals.java:85)
        at org.spockframework.lang.SpecInternals.thrownImpl(SpecInternals.java:72)

However, if I run the test as gradlew test --info, I see that the NullPointerException in the STANDARD_ERROR

com.amimas.MyClassSpec > NullPointerException will be thrown if expected json entities are not found STANDARD_ERROR
    java.lang.NullPointerException
        at com.amimas.RequestProcessor.validateRequest(RequestHandler.java:79)
        at com.amimas.RequestProcessor$validateRequest$0.call(Unknown Source)
        at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
        at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)

How to reproduce

1. Have a Java Class
2. Have a method in the class that throws exception
3. Add a spock test case to validate that expected exception is thrown

Link to a gist or similar (optional)

build.gradle:

apply plugin: 'groovy'

dependencies {	
	compile 'com.googlecode.json-simple:json-simple:1.1.1'

	testCompile 'org.slf4j:slf4j-api:1.7.25'
	testCompile 'org.codehaus.groovy:groovy-all:2.4.11'
	testCompile 'org.spockframework:spock-core:1.1-groovy-2.4'
	testRuntime 'com.athaydes:spock-reports:1.2.7'
}

RequestProcessor.java

package com.amimas.requests

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class RequestProcessor {
	private String user;
	private String location;
	private String request;

	public void setRequest(String request) {
		this.request = request;
	}
	public String getRequest() {
		return request;
	}

	public void validateRequest() throws NullPointerException {
		JSONParser parser = new JSONParser();
		try {
			JSONObject json = (JSONObject) parser.parse(this.getRequest());
			if(json.isEmpty() || json.size() != 2) {
				throw new Exception("invalid request");
			}
			aUser 	= (String) json.get("user");
			alocation = (String) json.get("location");
			
			if(aUser.trim().isEmpty() || alocation.trim().isEmpty()) {
					throw new Exception("invalid request format");
			}
		} catch (ParseException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
        }
}

RequestProcessorSpec.groovy

	def "NullPointerException will be thrown if expected json entities are not found" () {
		given:
			String request = '{"user":"john","location":"CA"}'
			RequestProcessor rp = new RequestProcessor()
			rp.setRequest(request)
		when: "a new instance of RequestHandler receives an empty request"
			rp.validateRequest()
		then: "an Exception being thrown"
			thrown(NullPointerException)

Additional Environment information

Version of your build tool(if used), Java, Groovy, IDE, OS etc

Java/JDK

JDK 1.8

Groovy version

Groovy 2.4

Build tool version

Gradle

Gradle 3.5

Operating System

Mac

IDE

n/a

Build-tool dependencies used

Gradle/Grails

testCompile 'org.spockframework:spock-core:1.1-groovy-2.4'

[sdoeringNew]

Is this your real code of the RequestProcessor? Then that's no issue with Spock.

First you never throw an NullPointerException in your code.
Second you catch all exceptions to log them. But you do not rethrow them. So the method will simply never fail.
Third your method accidentally creates a NPE - because it access a null-object somewhere. So you see a NPE as stacktrace.
Fourth the code simply does not reflect what you comment in your spec.

[amimas]

You're right. Thank you for the explanation.