Add testing of RegisterNative

* Add Java Class with native function in java/testing
* Add callback function in jnigi_testing_c_callback.go
* Add script testing.sh to compile java and run tests

Author: timob

.gitignore

@@ -0,0 +1 @@
+java/test/out/*

Dockerfile

@@ -18,6 +18,6 @@ RUN go mod download && go mod verify
 
 COPY . .
 
-CMD go test
+CMD ./testing.sh
 
 

java/test/javac.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+cd $(dirname $0)
+javac -d out -cp src/  src/local/*

java/test/src/local/JnigiTesting.java

@@ -0,0 +1,5 @@
+package local;
+
+public class JnigiTesting {
+	public native java.lang.String Greet(java.lang.String x);
+}

jnigi_test.go

@@ -6,6 +6,8 @@ package jnigi
 
 import (
 	"github.com/stretchr/testify/assert"
+	"os"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
@@ -28,6 +30,7 @@ func TestAll(t *testing.T) {
 	PTestPushPopLocalFrame(t)
 	PTestHandleException(t)
 	PTestCast(t)
+	PTestRegisterNative(t)
 	PTestDestroy(t)
 }
 
@@ -39,7 +42,8 @@ func PTestInit(t *testing.T) {
 		t.Fatal(err)
 	}
 	runtime.LockOSThread()
-	jvm2, e2, err := CreateJVM(NewJVMInitArgs(false, true, DEFAULT_VERSION, []string{"-Xcheck:jni"}))
+	cwd, _ := os.Getwd()
+	jvm2, e2, err := CreateJVM(NewJVMInitArgs(false, true, DEFAULT_VERSION, []string{"-Xcheck:jni", "-Djava.class.path=" + filepath.Join(cwd, "java/test/out")}))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -514,6 +518,28 @@ func PTestCast(t *testing.T) {
 	}
 }
 
+func PTestRegisterNative(t *testing.T) {
+	if err := env.RegisterNative("local/JnigiTesting", "Greet", ObjectType("java/lang/String"), []interface{}{ObjectType("java/lang/String")}, c_go_callback_Greet); err != nil {
+		t.Fatal(err)
+	}
+	objRef, err := env.NewObject("local/JnigiTesting")
+	if err != nil {
+		t.Fatal(err)
+	}
+	nameRef, err := env.NewObject("java/lang/String", []byte("World"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	strRef := NewObjectRef("java/lang/String")
+	if err := objRef.CallMethod(env, "Greet", strRef, nameRef); err != nil {
+		t.Fatal(err)
+	}
+	goStr := toGoStr(t, strRef)
+	if !assert.Equal(t, "Hello World!", goStr) {
+		t.Fail()
+	}
+}
+
 func toGoStr(t *testing.T, o *ObjectRef) string {
 	var goBytes []byte
 	if err := o.CallMethod(env, "getBytes", &goBytes); err != nil {

jnigi_test_c_callback.go

@@ -0,0 +1,34 @@
+//go:build cgo_testing
+
+package jnigi
+
+import (
+	"unsafe"
+)
+
+/*
+#include<stdint.h>
+
+extern uintptr_t go_callback_Greet(void *env, uintptr_t obj, uintptr_t arg_0 );
+
+*/
+import "C"
+
+//export go_callback_Greet
+func go_callback_Greet(jenv unsafe.Pointer, jobj uintptr, arg_0 uintptr) uintptr {
+	env := WrapEnv(jenv)
+	env.ExceptionHandler = ThrowableToStringExceptionHandler
+
+	strArgRef := WrapJObject(arg_0, "java/lang/String", false)
+	var goBytes []byte
+	if err := strArgRef.CallMethod(env, "getBytes", &goBytes); err != nil {
+		panic(err)
+	}
+	retRef, err := env.NewObject("java/lang/String", []byte("Hello "+string(goBytes)+"!"))
+	if err != nil {
+		panic(err)
+	}
+	return uintptr(retRef.JObject())
+}
+
+var c_go_callback_Greet = C.go_callback_Greet

testing.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+java/test/javac.sh && \
+go test -v --tags=cgo_testing