[BAEL-4131] division by zero unit tests

java-numbers-3/src/test/java/com/baeldung/divisionbyzero/DivisionByZeroUnitTest.java

@@ -0,0 +1,76 @@
+package com.baeldung.divisionbyzero;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class DivisionByZeroUnitTest {
+
+    @Test
+    void givenInt_whenDividedByZero_thenThrowException() {
+        assertThrows(ArithmeticException.class, () -> {
+            int result = 12 / 0;
+        });
+    }
+
+    @Test
+    void whenDividingIntZeroByZero_thenThrowException() {
+        assertThrows(ArithmeticException.class, () -> {
+            int result = 0 / 0;
+        });
+    }
+
+    @Test
+    void whenDividingFloatingNumberByZero_thenNoExceptionIsThrown() {
+        assertDoesNotThrow(() -> {
+            float result = 0f / 0;
+        });
+        assertDoesNotThrow(() -> {
+            double result = 0d / 0;
+        });
+    }
+
+    @Test
+    void givenPositiveFloatingNumber_whenDividedByZero_thenReturnPositiveInfinity() {
+        assertEquals(Float.POSITIVE_INFINITY, 12f / 0);
+        assertEquals(Double.POSITIVE_INFINITY, 12d / 0);
+    }
+
+    @Test
+    void givenNegativeFloatingNumber_whenDividedByZero_thenReturnNegativeInfinity() {
+        assertEquals(Float.NEGATIVE_INFINITY, -12f / 0);
+        assertEquals(Double.NEGATIVE_INFINITY, -12d / 0);
+    }
+
+    @Test
+    void givenPositiveFloatingNumber_whenDividedByNegativeZero_thenReturnNegativeInfinity() {
+        assertEquals(Float.NEGATIVE_INFINITY, 12f / -0f);
+        assertEquals(Double.NEGATIVE_INFINITY, 12f / -0f);
+    }
+
+    @Test
+    void whenDividingFloatingNumberZeroByZero_thenReturnNaN() {
+        assertEquals(Float.NaN, 0f / 0);
+        assertEquals(Double.NaN, 0d / 0);
+    }
+
+    @Test
+    void givenABitRepresentationWithAllExponentBitsZeroesAndAllFractionBitsZeroes_whenTransformingItToFloat_thenReturnPositiveZero() {
+        assertEquals(0f, Float.intBitsToFloat(0b00000000000000000000000000000000));
+        assertEquals(-0f, Float.intBitsToFloat(0b10000000000000000000000000000000));
+    }
+
+    @Test
+    void givenABitRepresentationWithAllExponentBitsOnesAndAllFractionBitsZeroes_whenTransformingItToFloat_thenReturnInfinity() {
+        assertEquals(Float.POSITIVE_INFINITY, Float.intBitsToFloat(0b01111111100000000000000000000000));
+        assertEquals(Float.NEGATIVE_INFINITY, Float.intBitsToFloat(0b11111111100000000000000000000000));
+    }
+
+    @Test
+    void givenABitRepresentationWithAllExponentBitsOnesAndNotAllFractionBitsZeroes_whenTransformingItToFloat_thenReturnNan() {
+        assertEquals(Float.NaN, Float.intBitsToFloat(0b11111111100000010000000000000000));
+        assertEquals(Float.NaN, Float.intBitsToFloat(0b11111111100000011000000000100000));
+        assertEquals(Float.NaN, Float.intBitsToFloat(0b11111111100000011100000000000000));
+        assertEquals(Float.NaN, Float.intBitsToFloat(0b11111111100000011110000000000000));
+    }
+}