[KTLN-571] Getting the Value of a Custom Property Defined in 'gradle.properties' in Kotlin

kotlin-build-plugins-1/build.gradle.kts

@@ -0,0 +1,41 @@
+plugins {
+    id("java")
+    kotlin("jvm") version "1.9.0"
+}
+
+group = "org.example"
+version = "1.0-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation(platform("org.junit:junit-bom:5.9.1"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+    implementation(kotlin("stdlib-jdk8"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+tasks.withType<Test> {
+    environment("CUSTOM_PROPERTY", project.findProperty("custom.property") as String)
+    environment("API_URL", project.findProperty("api.url") as String)
+}
+
+tasks.register<Copy>("generateCustomProperties") {
+    from("${project.rootDir}/gradle.properties")
+    into("src/generated/resources")
+    rename { "custom.properties" }
+}
+
+tasks.named<Copy>("processResources") {
+    dependsOn("generateCustomProperties")
+    from("src/generated/resources") {
+        include("custom.properties")
+    }
+}
+kotlin {
+    jvmToolchain(19)
+}

kotlin-build-plugins-1/settings.gradle.kts

@@ -0,0 +1,5 @@
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "0.5.0"
+}
+rootProject.name = "kotlin-build-plugins-1"
+

kotlin-build-plugins-1/src/test/kotlin/com/baeldung/getGradlePropertyValue/GetGradlePropertyValueUnitTest.kt

@@ -0,0 +1,30 @@
+package com.baeldung.getGradlePropertyValue
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+import java.util.Properties
+
+class GetGradlePropertyValueUnitTest {
+
+    @Test
+    fun `obtain environment variables using System getenv method`() {
+        val customProperty = System.getenv("CUSTOM_PROPERTY")
+        val apiUrl = System.getenv("API_URL")
+
+        assertEquals("CustomValue", customProperty)
+        assertEquals("https://api.example.com", apiUrl)
+    }
+
+    @Test
+    fun `obtain custom property value by loading properties from generated file`() {
+        val propertiesFileUrl = this::class.java.classLoader.getResource("custom.properties")
+            ?: throw IllegalStateException("Properties file not found")
+
+        val properties = Properties().apply {
+            propertiesFileUrl.openStream().use { load(it) }
+        }
+
+        assertEquals("CustomValue", properties.getProperty("custom.property"))
+        assertEquals("https://api.example.com", properties.getProperty("api.url"))
+    }
+}

kotlin-build-plugins/build.gradle.kts

@@ -19,3 +19,20 @@ dependencies {
     detektPlugins("io.gitlab.arturbosch.detekt:detekt-formatting:1.23.0")
     testImplementation(kotlin("test"))
 }
+//tasks.withType<Test> {
+//    environment("CUSTOM_PROPERTY", project.findProperty("custom.property") as String)
+//    environment("API_URL", project.findProperty("api.url") as String)
+//}
+//
+//tasks.register<Copy>("generateCustomProperties") {
+//    from("${project.rootDir}/gradle.properties")
+//    into("src/generated/resources")
+//    rename { "custom.properties" }
+//}
+//
+//tasks.named<Copy>("processResources") {
+//    dependsOn("generateCustomProperties")
+//    from("src/generated/resources") {
+//        include("custom.properties")
+//    }
+//}

kotlin-build-plugins/gradle.properties

@@ -0,0 +1,2 @@
+api.url=https://api.example.com
+custom.property=CustomValue

kotlin-build-plugins/src/test/kotlin/com/baeldung/getGradlePropertyValue/GetGradlePropertyValueUnitTest.kt

@@ -0,0 +1,32 @@
+package com.baeldung.getGradlePropertyValue
+
+import junit.framework.TestCase.assertEquals
+import org.junit.Test
+import java.io.File
+import java.util.Properties
+import java.io.FileInputStream
+
+class GetGradlePropertyValueUnitTest {
+
+    @Test
+    fun `obtain environment variables using System getenv method`() {
+        val customProperty = System.getenv("CUSTOM_PROPERTY")
+        val apiUrl = System.getenv("API_URL")
+
+        assertEquals("CustomValue", customProperty)
+        assertEquals("https://api.example.com", apiUrl)
+    }
+
+    @Test
+    fun `obtain custom property value by loading properties from generated file`() {
+        val propertiesFileUrl = this::class.java.classLoader.getResource("custom.properties")
+            ?: throw IllegalStateException("Properties file not found")
+
+        val properties = Properties().apply {
+            propertiesFileUrl.openStream().use { load(it) }
+        }
+
+        assertEquals("CustomValue", properties.getProperty("custom.property"))
+        assertEquals("https://api.example.com", properties.getProperty("api.url"))
+    }
+}