add codegen tests

Author: madsodgaard

Tests/JExtractSwiftTests/JNI/JNIClosureTests.swift

@@ -0,0 +1,129 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 JExtractSwiftLib
+import Testing
+
+@Suite
+struct JNIClosureTests {
+  let source =
+    """
+    public func emptyClosure(closure: () -> ()) {}
+    public func closureWithArgumentsAndReturn(closure: (Int64, Bool) -> Int64) {}
+    """
+
+  @Test
+  func emptyClosure_javaBindings() throws {
+    try assertOutput(input: source, .jni, .java, expectedChunks: [
+      """
+      public static class emptyClosure {
+        @FunctionalInterface
+        public interface closure {
+          void apply();
+        }
+      }
+      """,
+      """
+      /**
+        * Downcall to Swift:
+        * {@snippet lang=swift :
+        * public func emptyClosure(closure: () -> ())
+        * }
+        */
+      public static void emptyClosure(com.example.swift.SwiftModule.emptyClosure.closure closure) {
+        SwiftModule.$emptyClosure(closure);
+      }
+      """,
+      """
+      private static native void $emptyClosure(com.example.swift.SwiftModule.emptyClosure.closure closure);
+      """
+    ])
+  }
+
+  @Test
+  func emptyClosure_swiftThunks() throws {
+    try assertOutput(
+      input: source,
+      .jni,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: [
+        """
+        @_cdecl("Java_com_example_swift_SwiftModule__00024emptyClosure__Lcom_example_swift_SwiftModule_00024emptyClosure_00024closure_2")
+        func Java_com_example_swift_SwiftModule__00024emptyClosure__Lcom_example_swift_SwiftModule_00024emptyClosure_00024closure_2(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass, closure: jobject) {
+          SwiftModule.emptyClosure(closure: { 
+            let class$ = environment!.interface.GetObjectClass(environment, closure)
+            let methodID$ = environment!.interface.GetMethodID(environment, class$, "apply", "()V")!
+            let arguments$: [jvalue] = []
+            environment!.interface.CallVoidMethodA(environment, closure, methodID$, arguments$)
+          }
+          )
+        }
+        """
+      ]
+    )
+  }
+
+  @Test
+  func closureWithArgumentsAndReturn_javaBindings() throws {
+    try assertOutput(input: source, .jni, .java, expectedChunks: [
+      """
+      public static class closureWithArgumentsAndReturn {
+        @FunctionalInterface
+        public interface closure {
+          long apply(long _0, boolean _1);
+        }
+      }
+      """,
+      """
+      /**
+        * Downcall to Swift:
+        * {@snippet lang=swift :
+        * public func closureWithArgumentsAndReturn(closure: (Int64, Bool) -> Int64)
+        * }
+        */
+      public static void closureWithArgumentsAndReturn(com.example.swift.SwiftModule.closureWithArgumentsAndReturn.closure closure) {
+        SwiftModule.$closureWithArgumentsAndReturn(closure);
+      }
+      """,
+      """
+      private static native void $closureWithArgumentsAndReturn(com.example.swift.SwiftModule.closureWithArgumentsAndReturn.closure closure);
+      """
+    ])
+  }
+
+  @Test
+  func closureWithArgumentsAndReturn_swiftThunks() throws {
+    try assertOutput(
+      input: source,
+      .jni,
+      .swift,
+      detectChunkByInitialLines: 1,
+      expectedChunks: [
+        """
+        @_cdecl("Java_com_example_swift_SwiftModule__00024closureWithArgumentsAndReturn__Lcom_example_swift_SwiftModule_00024closureWithArgumentsAndReturn_00024closure_2")
+        func Java_com_example_swift_SwiftModule__00024closureWithArgumentsAndReturn__Lcom_example_swift_SwiftModule_00024closureWithArgumentsAndReturn_00024closure_2(environment: UnsafeMutablePointer<JNIEnv?>!, thisClass: jclass, closure: jobject) {
+          SwiftModule.closureWithArgumentsAndReturn(closure: { _0, _1 in
+            let class$ = environment!.interface.GetObjectClass(environment, closure)
+            let methodID$ = environment!.interface.GetMethodID(environment, class$, "apply", "(JZ)J")!
+            let arguments$: [jvalue] = [_0.getJValue(in: environment!), _1.getJValue(in: environment!)]
+            return Int64(fromJNI: environment!.interface.CallLongMethodA(environment, closure, methodID$, arguments$), in: environment!)
+          }
+          )
+        }
+        """
+      ]
+    )
+  }
+}