[KTLN-843] Add samples (#1040)

* [KTLN-843] Add samples

* [KTLN-843] Add samples

* [KTLN-843] Add samples

* [KTLN-843] Add samples

Author: LeoColman

kotlin-testing/pom.xml

@@ -64,6 +64,47 @@
             <version>${junit-jupiter-params.version}</version>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>io.kotest</groupId>
+            <artifactId>kotest-runner-junit5-jvm</artifactId>
+            <version>${kotest.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>io.kotest.extensions</groupId>
+            <artifactId>kotest-extensions-testcontainers</artifactId>
+            <version>${kotest-testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>${postgresql.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>io.mockk</groupId>
+            <artifactId>mockk</artifactId>
+            <version>${mockk.version}</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <build>
@@ -89,6 +130,11 @@
         <atrium.version>1.2.0</atrium.version>
         <jqwik.version>1.8.5</jqwik.version>
         <junit-jupiter-params.version>5.9.1</junit-jupiter-params.version>
+        <kotest.version>5.9.1</kotest.version>
+        <kotest-testcontainers.version>2.0.2</kotest-testcontainers.version>
+        <testcontainers.version>1.20.1</testcontainers.version>
+        <postgresql.version>42.7.3</postgresql.version>
+        <mockk.version>1.12.0</mockk.version>
     </properties>
 
 </project>

kotlin-testing/src/test/kotlin/com/baeldung/testresources/JUnitTestResourcesUnitTest.kt

@@ -0,0 +1,39 @@
+package com.baeldung.testresources
+
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+
+class JUnitTestResourcesUnitTest {
+
+    companion object {
+        @JvmStatic
+        @BeforeAll
+        fun setUpAll() {
+            println("Initializing Resources Before All Tests")
+        }
+
+        @JvmStatic
+        @AfterAll
+        fun tearDownAll() {
+            println("Cleaning Resources After All Tests")
+        }
+    }
+
+    @BeforeEach
+    fun setUp() {
+        println("Initializing Resources Before Each Test")
+    }
+
+    @AfterEach
+    fun tearDown() {
+        println("Cleaning Resources After Each Test")
+    }
+
+    @Test
+    fun testSomething() {
+        println("Running Test")
+    }
+}

kotlin-testing/src/test/kotlin/com/baeldung/testresources/KotestTestResourcesUnitTest.kt

@@ -0,0 +1,15 @@
+package com.baeldung.testresources
+
+import io.kotest.core.spec.style.StringSpec
+
+class KotestTestResourcesUnitTest : StringSpec({
+
+    beforeSpec { println("Initializing Resources Before All Tests") }
+    beforeTest { println("Initializing Resources Before Each Test") }
+    afterTest { println("Cleaning Resources After Each Test") }
+    afterSpec { println("Cleaning Resources After All Tests") }
+
+    "test something" {
+        println("Running Test")
+    }
+})

kotlin-testing/src/test/kotlin/com/baeldung/testresources/MockkTestResourcesUnitTest.kt

@@ -0,0 +1,33 @@
+package com.baeldung.testresources
+
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldBe
+import io.mockk.clearMocks
+import io.mockk.every
+import io.mockk.mockk
+import io.mockk.verify
+
+class OurClass(private val externalDependency: ExternalDependency) {
+    fun doWork() = externalDependency.functionToBeMocked()
+}
+
+class ExternalDependency {
+    fun functionToBeMocked(): String = "Real Result"
+}
+
+class MockkTestResourcesUnitTest : StringSpec({
+    val externalDependency: ExternalDependency = mockk()
+    val ourClass = OurClass(externalDependency)
+    beforeTest {
+        every { externalDependency.functionToBeMocked() } returns "mock response"
+    }
+    afterTest {
+        clearMocks(externalDependency)
+    }
+
+    "test doWork function" {
+        val result = ourClass.doWork()
+        result shouldBe "mock response"
+        verify { externalDependency.functionToBeMocked() }
+    }
+})

kotlin-testing/src/test/kotlin/com/baeldung/testresources/TestContainersResourceManagementLiveTest.kt

@@ -0,0 +1,26 @@
+package com.baeldung.testresources
+
+import io.kotest.core.extensions.install
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.extensions.testcontainers.JdbcDatabaseContainerExtension
+import io.kotest.matchers.shouldBe
+import org.testcontainers.containers.PostgreSQLContainer
+
+/**
+ * livetest. This class requires a docker environment to be setup on one's computer so that testcontainers can use
+ * it.
+ */
+class TestContainersResourceManagementLiveTest : StringSpec({
+    val dataSource = install(JdbcDatabaseContainerExtension(PostgreSQLContainer<Nothing>("postgres:latest")))
+
+    "test querying the database" {
+        val result = dataSource.connection.use {
+            it.createStatement().executeQuery("SELECT 1").use {
+                it.next()
+                it.getInt(1)
+            }
+        }
+
+        result shouldBe 1
+    }
+})