[KTLN-650] Add Samples (#952)

Author: LeoColman

core-kotlin-modules/core-kotlin-advanced-3/pom.xml

@@ -31,4 +31,40 @@
         <kotlinx-html-jvm.version>0.7.2</kotlinx-html-jvm.version>
     </properties>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${kotlin.version}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                        <configuration>
+                            <args>
+                                <arg>-Xcontext-receivers</arg>
+                            </args>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>test-compile</goal>
+                        </goals>
+                        <configuration>
+                            <args>
+                                <arg>-Xcontext-receivers</arg>
+                            </args>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
 </project>

core-kotlin-modules/core-kotlin-advanced-3/src/test/kotlin/com/baeldung/contextreceivers/ContextReceiversUnitTest.kt

@@ -0,0 +1,64 @@
+package com.baeldung.contextreceivers
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+context(StringBuilder)
+fun appendHello() {
+    append("Hello, ")
+}
+
+context(StringBuilder)
+fun appendWorld() {
+    append("World!")
+}
+
+class HtmlBuilder {
+    private val elements = mutableListOf<String>()
+    fun addElement(tag: String, content: String) {
+        elements.add("<$tag>$content</$tag>")
+    }
+
+    fun build(): String = elements.joinToString("\n")
+}
+
+context(HtmlBuilder) fun p(content: String) {
+    addElement("p", content)
+}
+
+context(HtmlBuilder) fun h1(content: String) {
+    addElement("h1", content)
+}
+
+class ContextReceiversUnitTest {
+
+    fun html(content: HtmlBuilder.() -> Unit): String {
+        val builder = HtmlBuilder()
+        builder.content()
+        return builder.build()
+    }
+
+    @Test
+    fun `test StringBuilder context receiver`() {
+        val builder = StringBuilder()
+        with(builder) {
+            appendHello()
+            appendWorld()
+        }
+        assertEquals("Hello, World!", builder.toString())
+    }
+
+    @Test
+    fun `test HTML DSL with context receivers`() {
+        val htmlContent = html {
+            h1("Welcome to My Website")
+            p("This is a paragraph in my website.")
+        }
+        val expected = """
+            <h1>Welcome to My Website</h1>
+            <p>This is a paragraph in my website.</p>
+            """.trimIndent()
+        assertEquals(expected, htmlContent)
+    }
+
+}