From ccd585fef6066180226fbd937fe7fcfea6234d05 Mon Sep 17 00:00:00 2001
From: Jan Ouwens <jan.ouwens@gmail.com>
Date: Wed, 8 Jan 2025 19:37:38 +0100
Subject: [PATCH] Adds Kotlin tests

---
 README.md                                     |   1 +
 equalsverifier-test-kotlin/pom.xml            | 117 ++++++++++++++++++
 .../KotlinCompilerGeneratedAnnotationTest.kt  |  31 +++++
 .../kotlin/KotlinFieldIterableTest.kt         |  38 ++++++
 .../kotlin/KotlinIntegrationTest.kt           |  39 ++++++
 pom.xml                                       |   2 +
 6 files changed, 228 insertions(+)
 create mode 100644 equalsverifier-test-kotlin/pom.xml
 create mode 100644 equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinCompilerGeneratedAnnotationTest.kt
 create mode 100644 equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinFieldIterableTest.kt
 create mode 100644 equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinIntegrationTest.kt

diff --git a/README.md b/README.md
index 7958b7efe..4de8638df 100644
--- a/README.md
+++ b/README.md
@@ -109,6 +109,7 @@ Here's a description of the modules:
 | equalsverifier-release-main   | release assembly for jar with dependencies                            |
 | equalsverifier-release-nodep  | release assembly for fat jar (with dependencies shaded in)            |
 | equalsverifier-release-verify | validation tests for the releases                                     |
+| equalsverifier-test-kotlin    | tests for Kotlin classes                                              |
 
 ## Signed JAR
 
diff --git a/equalsverifier-test-kotlin/pom.xml b/equalsverifier-test-kotlin/pom.xml
new file mode 100644
index 000000000..a30177dc2
--- /dev/null
+++ b/equalsverifier-test-kotlin/pom.xml
@@ -0,0 +1,117 @@
+<?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>
+    <parent>
+        <groupId>nl.jqno.equalsverifier</groupId>
+        <artifactId>equalsverifier-parent</artifactId>
+        <version>3.18.1-SNAPSHOT</version>
+    </parent>
+    <packaging>jar</packaging>
+
+    <artifactId>equalsverifier-test-kotlin</artifactId>
+    <name>EqualsVerifier | test Kotlin</name>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.jetbrains.kotlin</groupId>
+                <artifactId>kotlin-maven-plugin</artifactId>
+                <version>${version.kotlin}</version>
+                <executions>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                        <configuration>
+                            <sourceDirs>
+                                <source>src/main/kotlin</source>
+                                <source>target/generated-sources/annotations</source>
+                            </sourceDirs>
+                        </configuration>
+                    </execution>
+                    <execution>
+                        <id>test-compile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>test-compile</goal>
+                        </goals>
+                        <configuration>
+                            <sourceDirs>
+                                <source>src/test/kotlin</source>
+                                <source>target/generated-test-sources/test-annotations</source>
+                            </sourceDirs>
+                        </configuration>
+                    </execution>
+                </executions>
+                <configuration>
+                    <jvmTarget>1.8</jvmTarget>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>default-compile</id>
+                        <phase>none</phase>
+                    </execution>
+                    <execution>
+                        <id>default-testCompile</id>
+                        <phase>none</phase>
+                    </execution>
+                    <execution>
+                        <id>compile</id>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>compile</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>testCompile</id>
+                        <phase>test-compile</phase>
+                        <goals>
+                            <goal>testCompile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>nl.jqno.equalsverifier</groupId>
+            <artifactId>equalsverifier-core</artifactId>
+            <version>${project.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${version.junit-jupiter}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${version.assertj}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-stdlib-jdk8</artifactId>
+            <version>${version.kotlin}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jetbrains.kotlin</groupId>
+            <artifactId>kotlin-reflect</artifactId>
+            <version>${version.kotlin}</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+</project>
diff --git a/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinCompilerGeneratedAnnotationTest.kt b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinCompilerGeneratedAnnotationTest.kt
new file mode 100644
index 000000000..cd4fa2033
--- /dev/null
+++ b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinCompilerGeneratedAnnotationTest.kt
@@ -0,0 +1,31 @@
+package nl.jqno.equalsverifier.kotlin
+
+import nl.jqno.equalsverifier.EqualsVerifier
+import nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCache
+import nl.jqno.equalsverifier.internal.reflection.annotations.AnnotationCacheBuilder
+import nl.jqno.equalsverifier.internal.reflection.annotations.SupportedAnnotations
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+
+class KotlinCompilerGeneratedAnnotationTest {
+
+  val cache = AnnotationCache()
+  val cacheBuilder = AnnotationCacheBuilder(SupportedAnnotations.values(), HashSet())
+
+  @Test
+  fun `Kotlin classes are recognised as such`() {
+    assertThat(checkAnnotationFor(KotlinClass::class.java)).isTrue()
+  }
+
+  @Test
+  fun `Java classes are not recognised as Kotlin classes`() {
+    assertThat(checkAnnotationFor(EqualsVerifier::class.java)).isFalse()
+  }
+
+  private fun checkAnnotationFor(type: Class<*>): Boolean {
+    cacheBuilder.build(type, cache)
+    return cache.hasClassAnnotation(type, SupportedAnnotations.KOTLIN)
+  }
+}
+
+class KotlinClass
diff --git a/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinFieldIterableTest.kt b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinFieldIterableTest.kt
new file mode 100644
index 000000000..272b904d1
--- /dev/null
+++ b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinFieldIterableTest.kt
@@ -0,0 +1,38 @@
+package nl.jqno.equalsverifier.kotlin
+
+import org.junit.jupiter.api.Test
+import java.lang.reflect.Field
+import nl.jqno.equalsverifier.internal.reflection.FieldIterable
+import org.assertj.core.api.Assertions.assertThat
+
+class KotlinFieldIterableTest {
+  val actual = HashSet<Field>()
+
+  @Test
+  fun `FieldIterable ofKotlin ignores superclass backing fields`() {
+    actual.addAll(FieldIterable.ofKotlin(ImplementingDataClass::class.java).map { it.getField() })
+
+    assertThat(actual)
+      .isEqualTo(setOf(
+        Base::class.java.getDeclaredField("base"),
+        ImplementingDataClass::class.java.getDeclaredField("toOverride")))
+  }
+
+  @Test
+  fun `FieldIterable of does not ignore superclass backing fields`() {
+    actual.addAll(FieldIterable.of(ImplementingDataClass::class.java).map { it.getField() })
+
+    assertThat(actual)
+      .isEqualTo(setOf(
+        Base::class.java.getDeclaredField("base"),
+        Base::class.java.getDeclaredField("toOverride"),
+        ImplementingDataClass::class.java.getDeclaredField("toOverride")))
+  }
+
+  sealed class Base(
+    internal open val base: Int,
+    internal open val toOverride: Int,
+  )
+
+  data class ImplementingDataClass(override val toOverride: Int) : Base(42, toOverride)
+}
diff --git a/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinIntegrationTest.kt b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinIntegrationTest.kt
new file mode 100644
index 000000000..071ba26fd
--- /dev/null
+++ b/equalsverifier-test-kotlin/src/test/kotlin/nl/jqno/equalsverifier/kotlin/KotlinIntegrationTest.kt
@@ -0,0 +1,39 @@
+package nl.jqno.equalsverifier.kotlin
+
+import java.util.Objects
+import nl.jqno.equalsverifier.EqualsVerifier
+import org.junit.jupiter.api.Test
+
+class KotlinIntegrationTest {
+  @Test
+  fun `super's backing field does not affect implementing data class`() {
+    EqualsVerifier.forClass(ImplementingDataClass::class.java)
+      .withIgnoredFields("base")
+      .verify()
+  }
+
+  @Test
+  fun `super's backing field does not affect implementing regular class`() {
+    EqualsVerifier.forClass(ImplementingRegularClass::class.java)
+      .verify()
+  }
+
+  sealed class Base(
+    internal open val base: Int,
+    internal open val toOverride: Int,
+  )
+
+  data class ImplementingDataClass(override val toOverride: Int) : Base(42, toOverride)
+
+  class ImplementingRegularClass(override val toOverride: Int) : Base(42, toOverride) {
+    override fun equals(other: Any?): Boolean {
+      return other is ImplementingRegularClass
+        && base == other.base
+        && toOverride == other.toOverride
+    }
+
+    override fun hashCode(): Int {
+      return Objects.hash(base, toOverride)
+    }
+  }
+}
diff --git a/pom.xml b/pom.xml
index b7275309a..aa942fdc0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -89,6 +89,7 @@
         <version.jcip-annotations>1.0</version.jcip-annotations>
         <version.joda-time>2.13.0</version.joda-time>
         <version.junit-jupiter>5.11.4</version.junit-jupiter>
+        <version.kotlin>2.1.0</version.kotlin>
         <version.openjfx>19.0.2.1</version.openjfx>
         <version.slf4j>2.0.16</version.slf4j>
 
@@ -576,6 +577,7 @@
                 <module>equalsverifier-16</module>
                 <module>equalsverifier-17</module>
                 <module>equalsverifier-21</module>
+                <module>equalsverifier-test-kotlin</module>
                 <module>equalsverifier-aggregator</module>
                 <module>equalsverifier-release-main</module>
                 <module>equalsverifier-release-nodep</module>