Add test

base/src/test/kotlin/proguard/backport/LambdaExpressionConverterTest.kt

@@ -0,0 +1,78 @@
+/*
+ * ProGuard -- shrinking, optimization, obfuscation, and preverification
+ *             of Java bytecode.
+ *
+ * Copyright (c) 2002-2022 Guardsquare NV
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+package proguard.backport
+
+import io.kotest.core.spec.style.FreeSpec
+import io.kotest.matchers.shouldBe
+import io.kotest.matchers.shouldNotBe
+import proguard.classfile.attribute.visitor.AllAttributeVisitor
+import proguard.classfile.editor.InstructionSequenceBuilder
+import proguard.classfile.instruction.visitor.AllInstructionVisitor
+import proguard.classfile.util.InstructionSequenceMatcher
+import proguard.classfile.visitor.ClassPrinter
+import proguard.io.ExtraDataEntryNameMap
+import testutils.ClassPoolBuilder
+import testutils.JavaSource
+
+class LambdaExpressionConverterTest : FreeSpec({
+    "Given a lambda expression" - {
+        val (programClassPool, libraryClassPool) = ClassPoolBuilder.fromSource(
+            JavaSource(
+                "Test.java",
+                """
+                import java.util.function.Function;
+                public class Test {
+                    public void test() {
+                        foo(s -> s.length());
+                    }
+                    public void foo(Function<String, Integer> function) {
+                        System.out.println(function.apply("Hello")); 
+                    }
+                }
+                """.trimIndent()
+            )
+        )
+        programClassPool.classesAccept(ClassPrinter())
+        "When backported" - {
+            val lambdaExpressionConvertor = LambdaExpressionConverter(programClassPool, libraryClassPool, ExtraDataEntryNameMap(), null)
+            programClassPool.classesAccept("Test", lambdaExpressionConvertor)
+            programClassPool.classesAccept(ClassPrinter())
+            "Then a new class should be created" {
+                programClassPool.getClass("Test\$\$Lambda\$0") shouldNotBe null
+            }
+
+            "Then the invocation should call the backported lambda" {
+                val clazz = programClassPool.getClass("Test")
+                val builder = InstructionSequenceBuilder()
+                builder
+                    .aload_0()
+                    .getstatic("Test\$\$Lambda\$0", "INSTANCE", "LTest\$\$Lambda\$0;")
+                    .invokevirtual("Test", "foo", "(Ljava/util/function/Function;)V")
+                    .return_()
+
+                val matcher = InstructionSequenceMatcher(builder.constants(), builder.instructions())
+                clazz.methodAccept("test", "()V", AllAttributeVisitor(AllInstructionVisitor(matcher)))
+                matcher.isMatching shouldBe true
+            }
+        }
+    }
+})