Added Kotlin test, changed Kotlin version for OpenCV

cmake/android/android_gradle_projects.cmake

@@ -2,7 +2,7 @@
 set(ANDROID_GRADLE_PLUGIN_VERSION "7.3.1" CACHE STRING "Android Gradle Plugin version")
 message(STATUS "Android Gradle Plugin version: ${ANDROID_GRADLE_PLUGIN_VERSION}")
 
-set(KOTLIN_PLUGIN_VERSION "1.5.20" CACHE STRING "Kotlin Plugin version")
+set(KOTLIN_PLUGIN_VERSION "1.8.20" CACHE STRING "Kotlin Plugin version")
 message(STATUS "Kotlin Plugin version: ${KOTLIN_PLUGIN_VERSION}")
 
 if(BUILD_KOTLIN_EXTENSIONS)

modules/java/test/android_test/CMakeLists.txt

@@ -10,12 +10,13 @@ set(ANDROID_TESTS_SRC_DIRS
 
 set(ANDROID_TESTS_RES_DIR "'${OpenCV_SOURCE_DIR}/modules/java/test/common_test/res'" CACHE INTERNAL "")
 
-list(APPEND TEST_PROJECT_FILES "build.gradle" "CMakeLists.txt" "gradle.properties" "settings.gradle")
+list(APPEND TEST_PROJECT_FILES "CMakeLists.txt" "gradle.properties" "settings.gradle")
 foreach(TEST_PROJECT_FILE ${TEST_PROJECT_FILES})
     file(COPY "${CMAKE_CURRENT_SOURCE_DIR}/${TEST_PROJECT_FILE}" DESTINATION "${OPENCV_ANDROID_TEST_DIR}")
 endforeach()
 file(COPY "${CMAKE_CURRENT_SOURCE_DIR}/tests_module/AndroidManifest.xml" DESTINATION "${OPENCV_ANDROID_TEST_DIR}/tests_module")
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/tests_module/build.gradle.in" "${OPENCV_ANDROID_TEST_DIR}/tests_module/build.gradle" @ONLY)
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/build.gradle.in" "${OPENCV_ANDROID_TEST_DIR}/build.gradle" @ONLY)
 
 file(COPY "${OpenCV_SOURCE_DIR}/platforms/android/gradle-wrapper/gradlew" DESTINATION "${OPENCV_ANDROID_TEST_DIR}")
 file(COPY "${OpenCV_SOURCE_DIR}/platforms/android/gradle-wrapper/gradlew.bat" DESTINATION "${OPENCV_ANDROID_TEST_DIR}")

modules/java/test/android_test/build.gradle.in

@@ -7,8 +7,8 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.3.1'
-        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.20'
+        classpath 'com.android.tools.build:gradle:@ANDROID_GRADLE_PLUGIN_VERSION@'
+        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:@KOTLIN_PLUGIN_VERSION@'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files

modules/java/test/android_test/src/org/opencv/test/android/KotlinTest.kt

@@ -0,0 +1,25 @@
+package org.opencv.test.android
+
+import org.opencv.core.CvType
+import org.opencv.core.Mat
+import org.opencv.core.times
+import org.opencv.test.OpenCVTestCase
+import kotlin.math.abs
+
+class KotlinTest : OpenCVTestCase() {
+    fun testMatrixMultiplication() {
+        val m1 = Mat.ones(2, 3, CvType.CV_32F)
+        val m2 = Mat.ones(3, 2, CvType.CV_32F)
+
+        val m3 = m1.matMul(m2)
+        val m4 = m1 * m2
+
+        val value1 = floatArrayOf(3f)
+        m3.get(0, 1, value1)
+
+        val value2 = floatArrayOf(5f)
+        m4[0, 1, value2]
+
+        assertGE(0.001, abs(value1[0] - value2[0]).toDouble())
+    }
+}

modules/java/test/android_test/tests_module/build.gradle.in

@@ -1,4 +1,5 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 
 android {
     namespace 'org.opencv.tests'

platforms/android/ndk-25.config.py

@@ -9,7 +9,7 @@ cmake_common_vars = {
     # Docs: https://developer.android.com/studio/releases/gradle-plugin
     'ANDROID_GRADLE_PLUGIN_VERSION': '7.3.1',
     'GRADLE_VERSION': '7.5.1',
-    'KOTLIN_PLUGIN_VERSION': '1.5.20',
+    'KOTLIN_PLUGIN_VERSION': '1.8.20',
 }
 ABIs = [
     ABI("2", "armeabi-v7a", None, ndk_api_level=ANDROID_NATIVE_API_LEVEL, cmake_vars=cmake_common_vars),