content: import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.*;
  
  class CalculatorTest {
      @Test
      void onlyOne() {
          Calculator calculator = new Calculator();
          assertEquals(0, calculator.compute("0"));
          assertEquals(1, calculator.compute("1"));
          assertEquals(5, calculator.compute("5"));
      }
  
      @Test
      void verySimple() {
          Calculator calculator = new Calculator();
          assertEquals(0, calculator.compute("0 + 0"));
          assertEquals(1, calculator.compute("1 + 0"));
          assertEquals(2, calculator.compute("2 + 0"));
      }
  
      @Test
      void plus() {
          Calculator calculator = new Calculator();
          assertEquals(2, calculator.compute("1 + 1"));
          assertEquals(5, calculator.compute("2 + 3"));
      }
  
      @Test
      void minus() {
          Calculator calculator = new Calculator();
          assertEquals(1, calculator.compute("2 - 1"));
          assertEquals(-1, calculator.compute("2 - 3"));
      }
  
      @Test
      void times() {
          Calculator calculator = new Calculator();
          assertEquals(2, calculator.compute("2 * 1"));
          assertEquals(6, calculator.compute("2 * 3"));
      }
  
      @Test
      void divide() {
          Calculator calculator = new Calculator();
          assertEquals(2, calculator.compute("2 / 1"));
          assertEquals(5, calculator.compute("10 / 2"));
      }
  }
  