content: package com.alibaba.langengine.pubmed;
  
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.*;
  
  class PubMedExceptionTest {
  
      @Test
      void testMessageConstructor() {
          String message = "Test exception message";
          PubMedException exception = new PubMedException(message);
          assertEquals(message, exception.getMessage());
          assertNull(exception.getCause());
      }
  
      @Test
      void testMessageAndCauseConstructor() {
          String message = "Test exception message";
          Throwable cause = new RuntimeException("Cause exception");
          PubMedException exception = new PubMedException(message, cause);
          assertEquals(message, exception.getMessage());
          assertEquals(cause, exception.getCause());
      }
  
      @Test
      void testCauseConstructor() {
          String message = "Cause exception message";
          Throwable cause = new RuntimeException("Cause exception");
          PubMedException exception = new PubMedException(message, cause);
          assertEquals(message, exception.getMessage());
          assertEquals(cause, exception.getCause());
      }
  }
  