actually execute tests in JavaKitSampleApp not just run the app

Author: ktoso

Samples/JavaKitSampleApp/Sources/JavaKitExample/com/example/swift/HelloSwift.java

@@ -42,6 +42,11 @@ public void greet(String name) {
         System.out.println("Salutations, " + name);
     }
 
+    // method called 'init' to check we're able to handle these and not clash with swift 'init' keyword
+    public long init(long value) {
+        return value;
+    }
+
     public Predicate<Integer> lessThanTen() {
         Predicate<Integer> predicate = i -> (i < 10);
         return predicate;

Samples/JavaKitSampleApp/Tests/JavaKitExampleTests/JavaKitMethodCalledInitTests.swift

@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import JavaKitExample
+
+import SwiftJava
+import JavaUtilFunction
+import Testing
+
+@Suite
+struct JavaKitMethodCalledInitTests {
+
+  @Test
+  func test() throws {
+    let jvm = try JavaKitSampleJVM.shared()
+    let env = try jvm.environment()
+
+    let hello = HelloSwift(environment: env)
+    
+    let reply = hello.`init`(128)
+    #expect(reply == 128)
+  }
+
+}

Samples/JavaKitSampleApp/Tests/JavaKitExampleTests/JavaKitOptionalTests.swift

@@ -23,11 +23,7 @@ struct ManglingTests {
 
   @Test
   func methodMangling() throws {
-    let jvm = try! JavaVirtualMachine.shared(
-      classpath: [
-        ".build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/JavaCompilerPlugin/Java"
-      ]
-    )
+    let jvm = try JavaKitSampleJVM.shared()
     let env = try! jvm.environment()
 
     let helper = ThreadSafeHelperClass(environment: env)

Samples/JavaKitSampleApp/Tests/JavaKitExampleTests/JavaKitSampleJVM.swift

@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import JavaKitExample
+
+import SwiftJava
+import JavaUtilFunction
+
+/// Utility to configure the classpath and native libraries paths for writing tests against 
+/// classes defined in this JavaKitExample project
+struct JavaKitSampleJVM {
+
+  static func shared() throws -> JavaVirtualMachine {
+    try JavaVirtualMachine.shared(
+      classpath: [
+        ".build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/JavaCompilerPlugin/Java",
+      ],
+      vmOptions: [
+        KnownJavaVMOptions.javaLibraryPath(".build/\(SwiftPlatform.debugOrRelease)/"),
+      ]
+    )
+  }
+
+}

Samples/JavaKitSampleApp/ci-validate.sh

@@ -10,9 +10,14 @@ else
   DISABLE_EXPERIMENTAL_PREBUILTS='--disable-experimental-prebuilts'
 fi
 
-swift build $DISABLE_EXPERIMENTAL_PREBUILTS
+swift build --build-tests $DISABLE_EXPERIMENTAL_PREBUILTS
 
+echo "java application run: ..."
 "$JAVA_HOME/bin/java" \
     -cp .build/plugins/outputs/javakitsampleapp/JavaKitExample/destination/JavaCompilerPlugin/Java \
     -Djava.library.path=.build/debug \
     "com.example.swift.JavaKitSampleMain"
+echo "java application run: OK"
+
+
+swift test $DISABLE_EXPERIMENTAL_PREBUILTS

Sources/SwiftJava/KnownJavaVMOptions.swift

@@ -0,0 +1,22 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+public struct KnownJavaVMOptions {
+
+  /// Helper for the option to configure where native libraries should be searched for: `-Djava.library.path`
+  public static func javaLibraryPath(_ path: String) -> String {
+    return "-Djava.library.path=" + path
+  }
+
+}

Sources/SwiftJava/SwiftPlatform.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import CSwiftJavaJNI
+
+/// Helpers for forming platform specific directory names and paths.
+public struct SwiftPlatform {
+
+  public static var debugOrRelease: String { 
+    #if DEBUG
+      "debug"
+    #else 
+      "release"
+    #endif
+  }
+}

Sources/SwiftJavaRuntimeSupport/JNI.swift

@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift.org project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift.org project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftJava
+import CSwiftJavaJNI
+
+final class JNI {
+  static var shared: JNI!
+
+  let applicationClassLoader: JavaClassLoader
+
+  init(fromVM javaVM: JavaVirtualMachine) {
+    self.applicationClassLoader = try! JavaClass<JavaThread>(environment: javaVM.environment()).currentThread().getContextClassLoader()
+  }
+}
+
+// Called by generated code, and not automatically by Java.
+public func _JNI_OnLoad(_ javaVM: JavaVMPointer, _ reserved: UnsafeMutableRawPointer) {
+  JNI.shared = JNI(fromVM: JavaVirtualMachine(adoptingJVM: javaVM))
+}