### Question:
ProcessInfo { public Map<String, String> getEnvironmentVariables() { if (this.procEnv == null) { return Collections.emptyMap(); } if (this.environmentVariables == null) { this.environmentVariables = new HashMap<String, String>(this.procEnv.size()); SystemInfo systemInfo = SystemInfoFactory.createJavaSystemInfo(); boolean isWindows = systemInfo.getOperatingSystemType() == OperatingSystemType.WINDOWS; if (isWindows) { for (Map.Entry<String, String> env : this.procEnv.entrySet()) { this.environmentVariables.put(env.getKey().toUpperCase(), env.getValue()); } } else { this.environmentVariables.putAll(procEnv); } } return this.environmentVariables; } protected  ProcessInfo();  ProcessInfo(long pid);  ProcessInfo(long pid, SigarProxy sigar); void refresh(); ProcessInfoSnapshot priorSnaphot(); ProcessInfoSnapshot freshSnapshot(); void destroy(); long getPid(); String getName(); String getBaseName(); String[] getCommandLine(); Map<String, String> getEnvironmentVariables(); @Nullable String getEnvironmentVariable(@NotNull
    String name); @Deprecated long getParentPid(); @Deprecated ProcState getState(); @Deprecated ProcExe getExecutable(); @Deprecated ProcTime getTime(); @Deprecated ProcMem getMemory(); @Deprecated ProcCpu getCpu(); @Deprecated ProcFd getFileDescriptor(); @Deprecated ProcCred getCredentials(); @Deprecated ProcCredName getCredentialsName(); @Deprecated String getCurrentWorkingDirectory(); @Deprecated boolean isRunning(); AggregateProcessInfo getAggregateProcessTree(); ProcessInfo getParentProcess(); void kill(String signalName); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString();  }### Answer:
@Test public void testGetEmptyEnvironmentVariables() throws Exception { assertEquals(processInfo.getEnvironmentVariables(), Collections.EMPTY_MAP); }
@Test public void testGetEnvironmentVariables() throws Exception { Map<String, String> env = new HashMap<String, String>(); env.put("one", "1"); env.put("two", "2"); env.put("three", "3"); when(sigarProxy.getProcEnv(PID)).thenReturn(env); processInfo = new ProcessInfo(PID, sigarProxy); assertEquals(processInfo.getEnvironmentVariables(), env); }