Merge pull request #4760 from MajewskiKrzysztof/master

BAEL-1912

core-kotlin/src/test/kotlin/com/baeldung/random/RandomNumberTest.kt

@@ -0,0 +1,55 @@
+
+import org.junit.jupiter.api.Test
+import java.util.concurrent.ThreadLocalRandom
+import kotlin.test.assertTrue
+
+class RandomNumberTest {
+
+    @Test
+    fun whenRandomNumberWithJavaUtilMath_thenResultIsBetween0And1() {
+        val randomNumber = Math.random()
+        assertTrue { randomNumber >=0 }
+        assertTrue { randomNumber <= 1 }
+    }
+
+    @Test
+    fun whenRandomNumberWithJavaThreadLocalRandom_thenResultsInDefaultRanges() {
+        val randomDouble = ThreadLocalRandom.current().nextDouble()
+        val randomInteger = ThreadLocalRandom.current().nextInt()
+        val randomLong = ThreadLocalRandom.current().nextLong()
+        assertTrue { randomDouble >= 0 }
+        assertTrue { randomDouble <= 1 }
+        assertTrue { randomInteger >= Integer.MIN_VALUE }
+        assertTrue { randomInteger <= Integer.MAX_VALUE }
+        assertTrue { randomLong >= Long.MIN_VALUE }
+        assertTrue { randomLong <= Long.MAX_VALUE }
+    }
+
+    @Test
+    fun whenRandomNumberWithKotlinJSMath_thenResultIsBetween0And1() {
+        val randomDouble = Math.random()
+        assertTrue { randomDouble >=0 }
+        assertTrue { randomDouble <= 1 }
+    }
+
+    @Test
+    fun whenRandomNumberWithKotlinNumberRange_thenResultInGivenRange() {
+        val randomInteger = (1..12).shuffled().first()
+        assertTrue { randomInteger >= 1 }
+        assertTrue { randomInteger <= 12 }
+    }
+
+    @Test
+    fun whenRandomNumberWithJavaThreadLocalRandom_thenResultsInGivenRanges() {
+        val randomDouble = ThreadLocalRandom.current().nextDouble(1.0, 10.0)
+        val randomInteger = ThreadLocalRandom.current().nextInt(1, 10)
+        val randomLong = ThreadLocalRandom.current().nextLong(1, 10)
+        assertTrue { randomDouble >= 1 }
+        assertTrue { randomDouble <= 10 }
+        assertTrue { randomInteger >= 1 }
+        assertTrue { randomInteger <= 10 }
+        assertTrue { randomLong >= 1 }
+        assertTrue { randomLong <= 10 }
+    }
+
+}