feat: Add first tests

src/main/kotlin/app/revanced/patcher/resolver/SignatureResolver.kt

@@ -31,8 +31,8 @@ internal class SignatureResolver(
                     val classProxy = ClassProxy(classDef, index)
                     methodMap[signature.name] = SignatureResolverResult(
                         classProxy,
+                        patternScanData,
                         method.name,
-                        patternScanData
                     )
                 }
             }
@@ -53,8 +53,8 @@ internal class SignatureResolver(
                 val result = compareSignatureToMethod(signature, method) ?: continue
                 return SignatureResolverResult(
                     classProxy,
+                    result,
                     method.name,
-                    result
                 )
             }
             return null

src/main/kotlin/app/revanced/patcher/signature/SignatureResolverResult.kt

@@ -1,6 +1,7 @@
 package app.revanced.patcher.signature
 
 import app.revanced.patcher.proxy.ClassProxy
+import app.revanced.patcher.proxy.mutableTypes.MutableMethod
 import app.revanced.patcher.resolver.SignatureResolver
 
 /**
@@ -11,9 +12,14 @@ import app.revanced.patcher.resolver.SignatureResolver
  */
 data class SignatureResolverResult(
     val definingClassProxy: ClassProxy,
-    val resolvedMethodName: String,
+    val scanData: PatternScanResult,
-    val scanData: PatternScanResult?
+    private val resolvedMethodName: String,
 ) {
+
+    fun resolveAndGetMethod(): MutableMethod {
+        return definingClassProxy.resolve().methods.single { it.name == resolvedMethodName }
+    }
+
     @Suppress("Unused") // TODO(Sculas): remove this when we have coverage for this method.
     fun findParentMethod(signature: MethodSignature): SignatureResolverResult? {
         return SignatureResolver.resolveFromProxy(definingClassProxy, signature)

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

@@ -0,0 +1,128 @@
+package app.revanced.patcher
+
+import app.revanced.patcher.cache.Cache
+import app.revanced.patcher.extensions.or
+import app.revanced.patcher.patch.Patch
+import app.revanced.patcher.patch.PatchResult
+import app.revanced.patcher.patch.PatchResultSuccess
+import app.revanced.patcher.signature.MethodSignature
+import org.jf.dexlib2.AccessFlags
+import org.jf.dexlib2.Opcode
+import org.jf.dexlib2.builder.instruction.BuilderInstruction21c
+import org.jf.dexlib2.builder.instruction.BuilderInstruction35c
+import org.jf.dexlib2.immutable.reference.ImmutableMethodReference
+import org.jf.dexlib2.immutable.reference.ImmutableStringReference
+import org.junit.jupiter.api.Test
+import java.io.File
+
+internal class PatcherTest {
+    companion object {
+        val testSignatures: Array<MethodSignature> = arrayOf(
+            MethodSignature(
+                "main-method",
+                "V",
+                AccessFlags.PUBLIC or AccessFlags.STATIC,
+                setOf("[L"),
+                arrayOf(
+                    Opcode.CONST_STRING,
+                    Opcode.INVOKE_VIRTUAL,
+                    Opcode.RETURN_VOID
+                )
+            )
+        )
+    }
+
+    @Test
+    fun testPatcher() {
+        val patcher = Patcher(
+            File(PatcherTest::class.java.getResource("/test1.apk")!!.toURI()),
+            File("/"),
+            testSignatures
+        )
+
+        patcher.addPatches(
+            object : Patch("TestPatch") {
+                override fun execute(cache: Cache): PatchResult {
+                    // Get the result from the resolver cache
+                    val result = cache.resolvedMethods["main-method"]
+                    // Get the implementation for the resolved method
+                    val implementation = result.resolveAndGetMethod().implementation!!
+                    // Let's modify it, so it prints "Hello, ReVanced! Editing bytecode."
+                    // Get the start index of our opcode pattern.
+                    // This will be the index of the instruction with the opcode CONST_STRING.
+                    val startIndex = result.scanData.startIndex
+
+                    // the instruction format can be found via the docs at https://source.android.com/devices/tech/dalvik/dalvik-bytecode
+                    // in our case we want an instruction with the opcode CONST_STRING and the string "Hello, ReVanced! Editing bytecode."
+                    // the format is 21c, so we create a new BuilderInstruction21c
+                    // with the opcode CONST_STRING and the string "Hello, ReVanced! Editing bytecode."
+                    // This instruction will store the constant string reference in the register v1
+                    // For that a reference to the string is needed. It can be created by creating a ImmutableStringReference
+                    val stringInstruction1 = BuilderInstruction21c(
+                        Opcode.CONST_STRING,
+                        1,
+                        ImmutableStringReference("Hello, ReVanced! Editing bytecode.")
+                    )
+
+                    // Replace the instruction at index startIndex with a new instruction
+                    // We make sure to use this method to handle references  to it via labels in any case
+                    // If we are sure that the instruction is not referenced by any label, we can use the index operator overload
+                    // of the instruction list:
+                    // implementation.instructions[startIndex] = instruction
+                    implementation.replaceInstruction(startIndex, stringInstruction1)
+
+                    // Now lets print our string twice!
+
+                    // Create the necessary instructions (we could also clone the existing ones)
+                    val stringInstruction2 = BuilderInstruction21c(
+                        Opcode.CONST_STRING,
+                        1,
+                        ImmutableStringReference("Hello, ReVanced! Adding bytecode.")
+                    )
+                    val invokeInstruction = BuilderInstruction35c(
+                        Opcode.INVOKE_VIRTUAL,
+                        2, 0, 1, 0, 0, 0,
+                        ImmutableMethodReference(
+                            "Ljava.io.PrintStream;",
+                            "println",
+                            setOf("Ljava/lang/String;"),
+                            "V"
+                        )
+                    )
+
+                    // Insert our instructions after the second instruction by our pattern.
+                    implementation.addInstruction(startIndex + 1, stringInstruction2)
+                    implementation.addInstruction(startIndex + 3, invokeInstruction)
+
+                    // Finally, tell the patcher that this patch was a success.
+                    // You can also return PatchResultError with a message.
+                    // If an exception is thrown inside this function,
+                    // a PatchResultError will be returned with the error message.
+                    return PatchResultSuccess()
+                }
+            }
+        )
+
+        // Apply all patches loaded in the patcher
+        val patchResult = patcher.applyPatches()
+        // You can check if an error occurred
+        for ((patchName, result) in patchResult) {
+            if (result.isFailure) {
+                throw Exception("Patch $patchName failed", result.exceptionOrNull()!!)
+            }
+        }
+
+        patcher.save()
+    }
+
+    @Test
+    fun `test patcher with no changes`() {
+        Patcher(
+            File(PatcherTest::class.java.getResource("/test1.apk")!!.toURI()),
+            File("/no-changes-test"),
+            testSignatures
+        ).save()
+        // FIXME(Sculas): There seems to be a 1-byte difference, not sure what it is.
+        // assertEquals(available, out.size())
+    }
+}

src/test/kotlin/patcher/PatcherTest.kt

@@ -1,121 +0,0 @@
-package patcher
-
-import app.revanced.patcher.Patcher
-import app.revanced.patcher.cache.Cache
-import app.revanced.patcher.extensions.or
-import app.revanced.patcher.patch.Patch
-import app.revanced.patcher.patch.PatchResult
-import app.revanced.patcher.patch.PatchResultError
-import app.revanced.patcher.patch.PatchResultSuccess
-import app.revanced.patcher.signature.MethodSignature
-import app.revanced.patcher.smali.asInstruction
-import org.jf.dexlib2.AccessFlags
-import org.jf.dexlib2.Opcode
-import org.jf.dexlib2.builder.instruction.BuilderInstruction21t
-import org.jf.dexlib2.builder.instruction.BuilderInstruction35c
-import org.jf.dexlib2.iface.reference.MethodReference
-import org.jf.dexlib2.immutable.reference.ImmutableMethodReference
-import java.io.File
-import kotlin.test.assertContentEquals
-import kotlin.test.assertEquals
-
-fun main() {
-    val signatures = arrayOf(
-        MethodSignature(
-            "main-method",
-            "V",
-            AccessFlags.STATIC or AccessFlags.PUBLIC,
-            listOf("[O"),
-            arrayOf(
-                Opcode.SGET_OBJECT,
-                Opcode.CONST_STRING,
-                Opcode.INVOKE_VIRTUAL,
-                Opcode.RETURN_VOID
-            )
-        )
-    )
-
-    val patcher = Patcher(
-        File("black.apk"),
-        File("./"),
-        signatures
-    )
-
-    patcher.addPatches(
-        object : Patch("main-method-patch-via-proxy") {
-            override fun execute(cache: Cache): PatchResult {
-                val proxy = cache.findClass("XAdRemover")
-                    ?: return PatchResultError("Class 'XAdRemover' could not be found")
-
-                val xAdRemoverClass = proxy.resolve()
-                val hideReelMethod = xAdRemoverClass.methods.find {
-                    it.name.contains("HideReel")
-                }!!
-
-                val implementation = hideReelMethod.implementation!!
-
-                val readSettingsInstructionCompiled =
-                    "invoke-static { }, Lfi/razerman/youtube/XGlobals;->ReadSettings()V"
-                        .asInstruction() as BuilderInstruction35c
-                val readSettingsInstructionAssembled = BuilderInstruction35c(
-                    Opcode.INVOKE_STATIC,
-                    0, 0, 0, 0, 0, 0,
-                    ImmutableMethodReference(
-                        "Lfi/razerman/youtube/XGlobals;",
-                        "ReadSettings",
-                        emptyList(),
-                        "V"
-                    )
-                )
-
-                assertEquals(readSettingsInstructionAssembled.opcode, readSettingsInstructionCompiled.opcode)
-                assertEquals(
-                    readSettingsInstructionAssembled.referenceType,
-                    readSettingsInstructionCompiled.referenceType
-                )
-                assertEquals(
-                    readSettingsInstructionAssembled.registerCount,
-                    readSettingsInstructionCompiled.registerCount
-                )
-                assertEquals(readSettingsInstructionAssembled.registerC, readSettingsInstructionCompiled.registerC)
-                assertEquals(readSettingsInstructionAssembled.registerD, readSettingsInstructionCompiled.registerD)
-                assertEquals(readSettingsInstructionAssembled.registerE, readSettingsInstructionCompiled.registerE)
-                assertEquals(readSettingsInstructionAssembled.registerF, readSettingsInstructionCompiled.registerF)
-                assertEquals(readSettingsInstructionAssembled.registerG, readSettingsInstructionCompiled.registerG)
-                run {
-                    val compiledRef = readSettingsInstructionCompiled.reference as MethodReference
-                    val assembledRef = readSettingsInstructionAssembled.reference as MethodReference
-
-                    assertEquals(assembledRef.name, compiledRef.name)
-                    assertEquals(assembledRef.definingClass, compiledRef.definingClass)
-                    assertEquals(assembledRef.returnType, compiledRef.returnType)
-                    assertContentEquals(assembledRef.parameterTypes, compiledRef.parameterTypes)
-                }
-
-                implementation.addInstruction(
-                    21,
-                    readSettingsInstructionCompiled
-                )
-
-                // fix labels
-                // create a new label for the instruction we want to jump to
-                val newLabel = implementation.newLabelForIndex(21)
-                // replace all instances of the old label with the new one
-                implementation.replaceInstruction(4, BuilderInstruction21t(Opcode.IF_NEZ, 0, newLabel))
-                return PatchResultSuccess()
-            }
-        },
-        object : Patch("main-method-patch-via-signature") {
-            override fun execute(cache: Cache): PatchResult {
-                val mainMethodMap = cache.resolvedMethods["main-method"]
-                mainMethodMap.definingClassProxy.immutableClass.methods.single { method ->
-                    method.name == mainMethodMap.resolvedMethodName
-                }
-                return PatchResultSuccess()
-            }
-        }
-    )
-
-    patcher.applyPatches()
-    patcher.save()
-}