add case to test kotlin invoke java method

demo/kotlin-demo/src/main/kotlin/com/alibaba/testable/demo/PathUtil.kt

@@ -0,0 +1,27 @@
+package com.alibaba.testable.demo
+
+import java.io.File
+import java.io.IOException
+
+object PathUtil {
+
+    fun deleteRecursively(file: File) {
+        if (!file.exists()) {
+            return
+        }
+        val fileList = file.listFiles()
+        if (fileList != null) {
+            for (childFile in fileList) {
+                if (childFile.isDirectory) {
+                    deleteRecursively(childFile)
+                } else if (!childFile.delete()) {
+                    throw IOException()
+                }
+            }
+        }
+        if (file.exists() && !file.delete()) {
+            throw IOException("Unable to delete file " + file.absolutePath)
+        }
+    }
+
+}

demo/kotlin-demo/src/test/kotlin/com/alibaba/testable/demo/PathUtilTest.kt

@@ -0,0 +1,48 @@
+package com.alibaba.testable.demo
+
+import org.junit.jupiter.api.Test
+import com.alibaba.testable.core.annotation.TestableMock
+import com.alibaba.testable.core.tool.TestableTool.verify
+import java.io.File
+
+class PathUtilTest {
+
+    @TestableMock
+    fun exists(f: File): Boolean {
+        return when (f.absolutePath) {
+            "/a/b" -> true
+            "/a/b/c" -> true
+            else -> f.exists()
+        }
+    }
+
+    @TestableMock
+    fun isDirectory(f: File): Boolean {
+        return when (f.absolutePath) {
+            "/a/b/c" -> true
+            else -> f.isDirectory
+        }
+    }
+
+    @TestableMock
+    fun delete(f: File): Boolean {
+        return true
+    }
+
+    @TestableMock
+    fun listFiles(f: File): Array<File>? {
+        return when (f.absolutePath) {
+            "/a/b" -> arrayOf(File("/a/b/c"), File("/a/b/d"))
+            "/a/b/c" -> arrayOf(File("/a/b/c/e"))
+            else -> f.listFiles()
+        }
+    }
+
+    @Test
+    fun should_able_to_mock_java_method_invoke_in_kotlin() {
+        PathUtil.deleteRecursively(File("/a/b/"))
+        verify("listFiles").times(2)
+        verify("delete").times(4)
+    }
+
+}