Simple test for environmenta variable in jenkins

test.java

    @Issue("JENKINS-16255")
    @Test
    public void environmentalVariables() throws Exception{
        Map<String, String> env = new HashMap<>();
        env.put("http_proxy", "http://www.test.com");
        env.put("HTTP_PROXY", "http://www.test1.com");
        Slave slave = rule.createSlave(new EnvVars(env));

        FreeStyleProject project = rule.createFreeStyleProject();
        final CommandInterpreter script = Functions.isWindows()
                ? new BatchFile("echo %http_proxy%;echo %HTTP_PROXY%")
                : new Shell("echo ${http_proxy};echo ${HTTP_PROXY}")
                ;
        project.getBuildersList().add(script);
        project.setAssignedNode(slave.getComputer().getNode());

        FreeStyleBuild build = project.scheduleBuild2(0).get();
        
        rule.assertLogContains(String.format("echo %s", env.get("http_proxy")), build);
        rule.assertLogContains(String.format("echo %s", env.get("HTTP_PROXY")), build);
    }