2회차 과제 PR (차준혁)

src/main/java/Calculator.java

@@ -0,0 +1,67 @@
+public class Calculator {
+
+    private final String[] operationType = {"+", "-", "*", "/"};
+
+    public int calculate(String formula){
+        String[] input = formula.split(" ");
+        int result = Integer.parseInt(input[0]);
+        String operator = null;
+
+        for(int i = 1; i < input.length; i++){
+
+            if(isPermittedOperator(input[i])){
+                operator = input[i];
+            }else{
+                result = partCalculate(operator, result, input[i]);
+            }
+
+        }
+
+        return result;
+    }
+
+    public int partCalculate(String operator, int result, String input){
+
+        if(input == null || input.equals("")) throw new IllegalArgumentException();
+
+        switch (operator){
+            case "+":
+                return plus(result, input);
+            case "-":
+                return minus(result, input);
+            case "*":
+                return multiply(result, input);
+            case "/":
+                return division(result, input);
+            default:
+                throw new IllegalArgumentException();
+        }
+
+    }
+
+    private boolean isPermittedOperator(String input){
+
+        for(String operator : operationType){
+            if(input.equals(operator)) return true;
+        }
+
+        return false;
+    }
+
+    public int plus(int result, String input){
+        return result + Integer.parseInt(input);
+    }
+
+    public int minus(int result, String input){
+        return result - Integer.parseInt(input);
+    }
+
+    public int multiply(int result, String input){
+        return result * Integer.parseInt(input);
+    }
+
+    public int division(int result, String input){
+        return result / Integer.parseInt(input);
+    }
+
+}

src/test/java/CalculaorTest.java

@@ -0,0 +1,54 @@
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullAndEmptySource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+
+class CalculatorTest {
+
+    private final Calculator strcalculator = new Calculator();
+
+    @Test
+    void plusTest() {
+        assertThat(strcalculator.plus(2, "3")).isEqualTo(5);
+    }
+
+    @Test
+    void minusTest() {
+        assertThat(strcalculator.minus(10, "3")).isEqualTo(7);
+    }
+
+    @Test
+    void multiplyTest() {
+        assertThat(strcalculator.multiply(2, "5")).isEqualTo(10);
+    }
+
+    @Test
+    void divisionTest() {
+        assertThat(strcalculator.division(20, "2")).isEqualTo(10);
+    }
+
+    @Test
+    void calculateTest(){
+        assertThat(strcalculator.calculate("2 + 3 * 4 / 2")).isEqualTo(10);
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"#", "$"})
+    void partCalculatePermittedOperatorTest(String input){
+        assertThatIllegalArgumentException().isThrownBy(() -> {
+            assertThat(strcalculator.partCalculate(input, 5, "5")).isEqualTo(10);
+        });
+    }
+
+    @ParameterizedTest
+    @NullAndEmptySource
+    void partCalculateNullInputTest(String input){
+        assertThatIllegalArgumentException().isThrownBy(() -> {
+            assertThat(strcalculator.partCalculate("+", 5, input)).isEqualTo(10);
+        });
+    }
+}