feat: Add findParentMethod utility method (#4)

* feat: Add `findParentMethod` utitly method

* refactor: add `resolveMethod` to `MethodResolver`

added some assertions and some tests

Co-authored-by: Lucaskyy <contact@sculas.xyz>

src/test/kotlin/net/revanced/patcher/PatcherTest.kt

@@ -9,11 +9,13 @@ import net.revanced.patcher.util.ExtraTypes
 import net.revanced.patcher.util.TestUtil
 import net.revanced.patcher.writer.ASMWriter.insertAt
 import net.revanced.patcher.writer.ASMWriter.setAt
+import org.junit.jupiter.api.assertThrows
 import org.objectweb.asm.Opcodes.*
 import org.objectweb.asm.Type
 import org.objectweb.asm.tree.*
 import java.io.PrintStream
 import kotlin.test.Test
+import kotlin.test.assertEquals
 
 internal class PatcherTest {
     companion object {
@@ -145,4 +147,27 @@ internal class PatcherTest {
     //    out.close()
     //    testData.close()
     //}
+
+    @Test()
+    fun `should raise an exception because opcodes is empty`() {
+        val sigName = "testMethod"
+        val e = assertThrows<IllegalArgumentException>("Should raise an exception because opcodes is empty") {
+            Patcher(
+                PatcherTest::class.java.getResourceAsStream("/test1.jar")!!,
+                arrayOf(
+                    Signature(
+                        sigName,
+                        Type.VOID_TYPE,
+                        ACC_PUBLIC or ACC_STATIC,
+                        arrayOf(ExtraTypes.ArrayAny),
+                        emptyArray() // this is not allowed for non-search signatures!
+                    )
+                )
+            )
+        }
+        assertEquals(
+            "Opcode list for signature $sigName is empty. This is not allowed for non-search signatures.",
+            e.message
+        )
+    }
 }