JAVA-101 Split Core Kotlin

core-kotlin-modules/core-kotlin-testing/README.md

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+## Core Kotlin Testing
+
+This module contains articles about testing in Kotlin
+
+### Relevant articles:
+- [JUnit 5 for Kotlin Developers](https://www.baeldung.com/junit-5-kotlin)

core-kotlin-modules/core-kotlin-testing/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>core-kotlin-testing</artifactId>
+    <name>core-kotlin-testing</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-kotlin-modules</groupId>
+        <artifactId>core-kotlin-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-runner</artifactId>
+            <version>${junit.platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <junit.platform.version>1.1.1</junit.platform.version>
+    </properties>
+
+</project>

core-kotlin-modules/core-kotlin-testing/src/test/kotlin/com/baeldung/junit5/Calculator.kt

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+package com.baeldung.junit5
+
+class Calculator {
+    fun add(a: Int, b: Int) = a + b
+
+    fun divide(a: Int, b: Int) = if (b == 0) {
+        throw DivideByZeroException(a)
+    } else {
+        a / b
+    }
+
+    fun square(a: Int) = a * a
+
+    fun squareRoot(a: Int) = Math.sqrt(a.toDouble())
+
+    fun log(base: Int, value: Int) = Math.log(value.toDouble()) / Math.log(base.toDouble())
+}

core-kotlin-modules/core-kotlin-testing/src/test/kotlin/com/baeldung/junit5/CalculatorUnitTest.kt

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+package com.baeldung.junit5
+
+import org.junit.jupiter.api.*
+import org.junit.jupiter.api.function.Executable
+
+class CalculatorUnitTest {
+    private val calculator = Calculator()
+
+    @Test
+    fun `Adding 1 and 3 should be equal to 4`() {
+        Assertions.assertEquals(4, calculator.add(1, 3))
+    }
+
+    @Test
+    fun `Dividing by zero should throw the DivideByZeroException`() {
+        val exception = Assertions.assertThrows(DivideByZeroException::class.java) {
+            calculator.divide(5, 0)
+        }
+
+        Assertions.assertEquals(5, exception.numerator)
+    }
+
+    @Test
+    fun `The square of a number should be equal to that number multiplied in itself`() {
+        Assertions.assertAll(
+                Executable { Assertions.assertEquals(1, calculator.square(1)) },
+                Executable { Assertions.assertEquals(4, calculator.square(2)) },
+                Executable { Assertions.assertEquals(9, calculator.square(3)) }
+        )
+    }
+
+    @TestFactory
+    fun testSquaresFactory() = listOf(
+            DynamicTest.dynamicTest("when I calculate 1^2 then I get 1") { Assertions.assertEquals(1,calculator.square(1))},
+            DynamicTest.dynamicTest("when I calculate 2^2 then I get 4") { Assertions.assertEquals(4,calculator.square(2))},
+            DynamicTest.dynamicTest("when I calculate 3^2 then I get 9") { Assertions.assertEquals(9,calculator.square(3))}
+    )
+
+    @TestFactory
+    fun testSquaresFactory2() = listOf(
+            1 to 1,
+            2 to 4,
+            3 to 9,
+            4 to 16,
+            5 to 25)
+            .map { (input, expected) ->
+                DynamicTest.dynamicTest("when I calculate $input^2 then I get $expected") {
+                    Assertions.assertEquals(expected, calculator.square(input))
+                }
+            }
+
+    private val squaresTestData = listOf(
+            1 to 1,
+            2 to 4,
+            3 to 9,
+            4 to 16,
+            5 to 25)
+
+    @TestFactory
+    fun testSquaresFactory3() = squaresTestData
+            .map { (input, expected) ->
+                DynamicTest.dynamicTest("when I calculate $input^2 then I get $expected") {
+                    Assertions.assertEquals(expected, calculator.square(input))
+                }
+            }
+    @TestFactory
+    fun testSquareRootsFactory3() = squaresTestData
+            .map { (expected, input) ->
+                DynamicTest.dynamicTest("I calculate the square root of $input then I get $expected") {
+                    Assertions.assertEquals(expected.toDouble(), calculator.squareRoot(input))
+                }
+            }
+
+    @Tags(
+            Tag("slow"),
+            Tag("logarithms")
+    )
+    @Test
+    fun `Log to base 2 of 8 should be equal to 3`() {
+        Assertions.assertEquals(3.0, calculator.log(2, 8))
+    }
+}

core-kotlin-modules/core-kotlin-testing/src/test/kotlin/com/baeldung/junit5/DivideByZeroException.kt

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+package com.baeldung.junit5
+
+class DivideByZeroException(val numerator: Int) : Exception()

core-kotlin-modules/core-kotlin-testing/src/test/kotlin/com/baeldung/junit5/SimpleUnitTest.kt

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+package com.baeldung.junit5
+
+import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Disabled
+import org.junit.jupiter.api.Test
+
+class SimpleUnitTest {
+
+    @Test
+    fun `isEmpty should return true for empty lists`() {
+        val list = listOf<String>()
+        Assertions.assertTrue(list::isEmpty)
+    }
+
+    @Test
+    @Disabled
+    fun `3 is equal to 4`() {
+        Assertions.assertEquals(3, 4) {
+            "Three does not equal four"
+        }
+    }
+}