test: Add test project for arrow-optics with Maven configuration and sample tests #63

Makefile

@@ -47,6 +47,8 @@ ci:
 		mvn install -DskipTests && \
 		echo "🧩 Testing with sample project" && \
 		(cd sample-project && mvn -Dksp.plugin.version=$(PROJECT_VERSION) test) && \
+		echo "🧩 Testing with arrow-optics-test" && \
+		(cd test-projects/arrow-optics && mvn -Dksp.plugin.version=$(PROJECT_VERSION) test) && \
 		echo "✅ Done"
 
 .PHONY:sample

sample-project/pom.xml

@@ -9,7 +9,7 @@
     <properties>
         <kotlin.version>2.3.10</kotlin.version>
         <maven.compiler.release>11</maven.compiler.release>
-        <ksp.plugin.version>0.3.0</ksp.plugin.version>
+        <ksp.plugin.version>0.3.2</ksp.plugin.version>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 

test-projects/arrow-optics/pom.xml

@@ -0,0 +1,115 @@
+<?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>
+
+    <groupId>com.example</groupId>
+    <artifactId>arrow-optics-test</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <kotlin.version>2.3.10</kotlin.version>
+        <arrow.version>2.2.1.1</arrow.version>
+        <maven.compiler.release>11</maven.compiler.release>
+        <ksp.plugin.version>0.3.2</ksp.plugin.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib</artifactId>
+            <version>${kotlin.version}</version>
+        </dependency>
+
+        <!--
+            IMPORTANT: arrow-optics MUST be a project compile dependency (not a plugin dependency).
+            The KSP processor needs to resolve the @optics annotation type from the project classpath.
+            Without this, the processor finds no annotated classes and generates nothing.
+        -->
+        <dependency>
+            <groupId>io.arrow-kt</groupId>
+            <artifactId>arrow-optics</artifactId>
+            <version>${arrow.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.arrow-kt</groupId>
+            <artifactId>arrow-core</artifactId>
+            <version>${arrow.version}</version>
+        </dependency>
+
+        <!-- Test dependencies -->
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-test-junit5</artifactId>
+            <version>${kotlin.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.0</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <sourceDirectory>src/main/kotlin</sourceDirectory>
+        <testSourceDirectory>src/test/kotlin</testSourceDirectory>
+
+        <plugins>
+            <plugin>
+                <groupId>me.kpavlov.ksp.maven</groupId>
+                <artifactId>ksp-maven-plugin</artifactId>
+                <version>${ksp.plugin.version}</version>
+                <!-- REQUIRED: allows plugin to register generated sources in the build lifecycle -->
+                <extensions>true</extensions>
+                <configuration>
+                    <debug>true</debug>
+                </configuration>
+                <dependencies>
+                    <!--
+                        arrow-optics-ksp-plugin is the KSP symbol processor.
+                        It MUST be a plugin dependency (not a project dependency),
+                        so that Maven's plugin classloader can discover it via ServiceLoader.
+                    -->
+                    <dependency>
+                        <groupId>io.arrow-kt</groupId>
+                        <artifactId>arrow-optics-ksp-plugin</artifactId>
+                        <version>${arrow.version}</version>
+                    </dependency>
+                </dependencies>
+                <!-- No explicit <executions> needed: the plugin's lifecycle extension
+                     automatically binds process (main) to generate-sources and
+                     process-test (test sources) to generate-test-sources. -->
+            </plugin>
+
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${kotlin.version}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                        <phase>compile</phase>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <goals>
+                            <goal>test-compile</goal>
+                        </goals>
+                        <phase>test-compile</phase>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.5.4</version>
+            </plugin>
+        </plugins>
+    </build>
+</project>

test-projects/arrow-optics/src/main/kotlin/com/example/Person.kt

@@ -0,0 +1,39 @@
+package com.example
+
+import arrow.optics.optics
+
+/**
+ * A data class annotated with @optics.
+ *
+ * Arrow KSP processor generates Lens/Prism/Optional optics for each property.
+ * The companion object is REQUIRED for the generated extension properties to attach to.
+ *
+ * ```
+ * Generated (by arrow-optics-ksp-plugin):
+ *   Person.name   : Lens<Person, String>
+ *   Person.age    : Lens<Person, Int>
+ *   Person.address: Lens<Person, Address>
+ */
+@optics
+data class Person(
+    val name: String,
+    val age: Int,
+    val address: Address,
+) {
+    companion object
+}
+
+/**
+ * A nested data class also annotated with @optics.
+ *
+ * Generated (by arrow-optics-ksp-plugin):
+ *   Address.street: Lens<Address, String>
+ *   Address.city  : Lens<Address, String>
+ */
+@optics
+data class Address(
+    val street: String,
+    val city: String,
+) {
+    companion object
+}

test-projects/arrow-optics/src/test/kotlin/com/example/PersonOpticsTest.kt

@@ -0,0 +1,57 @@
+package com.example
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+/**
+ * Verifies that arrow-optics-ksp-plugin successfully generated optics for Person and Address.
+ *
+ * If these tests fail to compile, the KSP processor did not generate the optics.
+ * Check:
+ *  1. arrow-optics is in project <dependencies> (compile scope), not only in plugin <dependencies>
+ *  2. The @optics annotation is applied and companion object is present
+ *  3. Generated sources dir (target/generated-sources/ksp) is on the compile source path
+ */
+class PersonOpticsTest {
+
+    @Test
+    fun `Lens modifies name`() {
+        val person = Person(name = "john", age = 30, address = Address("Main St", "New York"))
+
+        // Person.name is a generated Lens<Person, String>
+        val updated = Person.name.modify(person) { it.replaceFirstChar(Char::uppercaseChar) }
+
+        assertEquals("John", updated.name)
+        assertEquals(30, updated.age)
+    }
+
+    @Test
+    fun `Lens replaces age`() {
+        val person = Person(name = "John", age = 30, address = Address("Main St", "New York"))
+
+        val updated = Person.age.set(person, 31)
+
+        assertEquals(31, updated.age)
+        assertEquals("John", updated.name)
+    }
+
+    @Test
+    fun `composed Lens modifies nested city`() {
+        val person = Person(name = "John", age = 30, address = Address("Main St", "New York"))
+
+        // Compose Person.address (Lens<Person,Address>) with Address.city (Lens<Address,String>)
+        val cityLens = Person.address compose Address.city
+        val updated = cityLens.set(person, "London")
+
+        assertEquals("London", updated.address.city)
+        assertEquals("Main St", updated.address.street)
+    }
+
+    @Test
+    fun `Lens get reads property`() {
+        val person = Person(name = "Alice", age = 25, address = Address("Elm St", "Boston"))
+
+        assertEquals("Alice", Person.name.get(person))
+        assertEquals("Boston", Address.city.get(person.address))
+    }
+}