CalculatorTest.java

import static org.junit.Assert.*;

import java.util.Arrays;

import org.junit.Before;
import org.junit.Test;

import dev.util.inscriptions.Calculator;

public class CalculatorTest {

    private Calculator calculator;

    @Before
    public void setUp() throws Exception {
        calculator = new Calculator();
    }

    @Test(expected = IllegalArgumentException.class)
    public void testCalcInvalidParams() throws Exception {
        calculator.calcWithArray(Arrays.asList("1", "+"));
    }

    @Test(expected = IllegalArgumentException.class)
    public void testCalcInvalidParams2() throws Exception {
        calculator.calcWithArray(Arrays.asList("1"));
    }

    @Test(expected = IllegalArgumentException.class)
    public void testCalcInvalidParams3() throws Exception {
        calculator.calcWithArray(Arrays.asList("/"));
    }

    @Test
    public void testCalcSum() throws Exception {
        Double expected = 1000D;
        Double actual = calculator.calcWithArray(Arrays.asList("1", "+", "999"));
        assertEquals(expected, actual);
    }
}