implement calculator and write tests

src/main/java/core/basesyntax/Calculator.java

@@ -0,0 +1,29 @@
+package core.basesyntax;
+
+public class Calculator {
+    private static final char PLUS_SIGN = '+';
+    private static final char MINUS_SIGN = '-';
+    private static final char MULTIPLY_SIGN = '*';
+    private static final char DIVIDE_SIGN = '/';
+    private static final char RAISING_SIGN = '^';
+
+    double calculate(double firstValue, double secondValue, char operation) {
+        switch (operation) {
+            case PLUS_SIGN:
+                return firstValue + secondValue;
+            case MINUS_SIGN:
+                return firstValue - secondValue;
+            case MULTIPLY_SIGN:
+                return firstValue * secondValue;
+            case DIVIDE_SIGN:
+                if (secondValue == 0) {
+                    throw new ArithmeticException("Division by zero is forbidden");
+                }
+                return firstValue / secondValue;
+            case RAISING_SIGN:
+                return Math.pow(firstValue,secondValue);
+            default:
+                throw new IllegalArgumentException("Argument is illegal");
+        }
+    }
+}

src/test/java/core/basesyntax/CalculatorTest.java

@@ -0,0 +1,299 @@
+package core.basesyntax;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class CalculatorTest {
+    private static final char ADDITION_SIGN = '+';
+    private static final char SUBTRACTION_SIGN = '-';
+    private static final char MULTIPLICATION_SIGN = '*';
+    private static final char DIVISION_SIGN = '/';
+    private static final char RAISING_SIGN = '^';
+    private static final double DELTA = 0.0001;
+    private Calculator calculator;
+    private double expected;
+    private double actual;
+
+    @BeforeEach
+    void setUp() {
+        calculator = new Calculator();
+    }
+
+    @Test
+    void calculate_additionWithPositiveOperands_IsOk() {
+        expected = 13.37;
+        actual = calculator.calculate(12.37,1, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithNegativeOperands_IsOk() {
+        expected = -14.01;
+        actual = calculator.calculate(-12,-2.01, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithOneNegativeOperandAndOnePositive_IsOk() {
+        expected = -36;
+        actual = calculator.calculate(-100,64, ADDITION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(64,-100, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionWithZero_IsOk() {
+        expected = 0.02;
+        actual = calculator.calculate(0,0.02, ADDITION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(0.02,0, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionMaxOperands_IsOk() {
+        expected = Double.POSITIVE_INFINITY;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_additionMinOperands_IsOk() {
+        expected = Double.MIN_VALUE + Double.MIN_VALUE;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, ADDITION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithPositiveOperands_IsOk() {
+        expected = 401;
+        actual = calculator.calculate(800,399,SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithNegativeOperands_IsOk() {
+        expected = 5;
+        actual = calculator.calculate(-10,-15, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithOneNegativeOperandAndOnePositive_IsOk() {
+        expected = 110;
+        actual = calculator.calculate(90,-20,SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+        expected = -60;
+        actual = calculator.calculate(-40,20, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    void calculate_subtractionWithZero_IsOk() {
+        expected = -1;
+        actual = calculator.calculate(-1,0, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(-1,0, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_subtractionMinAndMaxValues_IsOk() {
+        expected = -Double.MAX_VALUE;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MAX_VALUE, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_subtractionMaxMinValues_IsOk() {
+        expected = Double.MAX_VALUE;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_subtractionMaxValues_IsOk() {
+        expected = 0;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+
+    }
+
+    @Test
+    public void calculate_subtractionIfBothOperandsAreMinValues_IsOk() {
+        expected = 0;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, SUBTRACTION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_multiplicationOfTwoPositiveOperands_IsOk() {
+        expected = 200;
+        actual = calculator.calculate(20, 10, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_multiplicationOfTwoNegativeOperands_IsOk() {
+        expected = 8;
+        actual = calculator.calculate(-2, -4, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_multiplicationOfPositiveAndNegative_IsOk() {
+        expected = -60;
+        actual = calculator.calculate(-15, 4, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(4, -15, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_multiplicationZero_IsOk() {
+        expected = 0;
+        actual = calculator.calculate(0, 2, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(2, 0, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+        actual = calculator.calculate(0, 0, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_multiplicationMinMax_IsOk() {
+        expected = Double.MIN_VALUE;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MAX_VALUE, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual, DELTA);
+        expected = Double.POSITIVE_INFINITY;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual, DELTA);
+        expected = 0;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, MULTIPLICATION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionTwoPositiveOperands_IsOk() {
+        expected = 2;
+        actual = calculator.calculate(6, 3, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionTwoNegativeOperands_IsOk() {
+        expected = 1;
+        actual = calculator.calculate(-1, -1, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionPositiveNegative_IsOk() {
+        expected = -16;
+        actual = calculator.calculate(32, -2, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+        expected = -0.0625;
+        actual = calculator.calculate(-2, 32, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionFirstOperandEqualsZero_IsOk() {
+        expected = 0;
+        actual = calculator.calculate(0, 10, DIVISION_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_divisionSecondOperandEqualsZero_isNotOk() {
+        assertThrows(ArithmeticException.class,
+                () -> calculator.calculate(5, 0, DIVISION_SIGN));
+    }
+
+    @Test
+    public void calculate_divisionMinAndMaxValues_IsOk() {
+        expected = Double.POSITIVE_INFINITY;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionMaxAndMinValues_IsOk() {
+        expected = Double.POSITIVE_INFINITY;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MIN_VALUE, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionOperandsAreMaxValues_IsOk() {
+        expected = 1;
+        actual = calculator.calculate(Double.MAX_VALUE, Double.MAX_VALUE, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_divisionOperandsAreMinValues_IsOk() {
+        expected = 1;
+        actual = calculator.calculate(Double.MIN_VALUE, Double.MIN_VALUE, DIVISION_SIGN);
+        assertEquals(expected, actual, DELTA);
+    }
+
+    @Test
+    public void calculate_raisePositiveValueToPositiveValue_IsOk() {
+        expected = 4;
+        actual = calculator.calculate(2, 2, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raisePositiveValueToNegativeValue_IsOk() {
+        expected = 0.25;
+        actual = calculator.calculate(2, -2, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raiseNegativeValueToPositiveValue_IsOk() {
+        expected = -64;
+        actual = calculator.calculate(-4,3, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raiseNegativeValueToNegativeValue_IsOk() {
+        expected = -0.008;
+        actual = calculator.calculate(-5, -3, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raisePositiveValueToZero_IsOk() {
+        expected = 1;
+        actual = calculator.calculate(10, 0, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raiseNegativeValueToZero_IsOk() {
+        expected = 1;
+        actual = calculator.calculate(-2, 0, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_raiseZeroValueToPositiveValue_IsOk() {
+        expected = 0;
+        actual = calculator.calculate(0, 2, RAISING_SIGN);
+        assertEquals(expected, actual);
+    }
+
+    @Test
+    public void calculate_illegalOperation_isNotOk() {
+        assertThrows(IllegalArgumentException.class, ()
+                -> calculator.calculate(10, 25, '='));
+    }
+}