#vulnerable code 
                                @Test
    public void testStepPublishValues() throws Exception {
        URL resource = getClass().getResource("/yaml/binding_scope_flow.sl");
        URI operation = getClass().getResource("/yaml/binding_scope_op.sl").toURI();
        Set<SlangSource> path = Sets.newHashSet(SlangSource.fromFile(operation));
        CompilationArtifact compilationArtifact = slang.compile(SlangSource.fromFile(resource.toURI()), path);

        Map<String, Value> userInputs = Collections.emptyMap();
        Set<SystemProperty> systemProperties = Collections.emptySet();

        // trigger ExecutionPlan
        RuntimeInformation runtimeInformation = triggerWithData(compilationArtifact, userInputs, systemProperties);

        Map<String, StepData> executionData = runtimeInformation.getSteps();

        StepData stepData = executionData.get(FIRST_STEP_PATH);
        Assert.assertNotNull("step data is null", stepData);

        verifyStepPublishValues(stepData);
    } 
                            #location 19 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void testStepPublishValues() throws Exception {
        URL resource = getClass().getResource("/yaml/binding_scope_flow.sl");
        URI operation = getClass().getResource("/yaml/binding_scope_op.sl").toURI();
        Set<SlangSource> path = Sets.newHashSet(SlangSource.fromFile(operation));
        CompilationArtifact compilationArtifact = slang.compile(SlangSource.fromFile(resource.toURI()), path);

        Map<String, Value> userInputs = Collections.emptyMap();
        Set<SystemProperty> systemProperties = Collections.emptySet();

        // trigger ExecutionPlan
        RuntimeInformation runtimeInformation = triggerWithData(compilationArtifact, userInputs, systemProperties);

        Map<String, StepData> executionData = runtimeInformation.getSteps();

        StepData stepData = executionData.get(FIRST_STEP_PATH);
        Assert.assertNotNull("step data is null", stepData);
    }