[Bug] Unit Tests: java.lang.UnsatisfiedLinkError: 'byte[][] net.ankiweb.rsdroid.NativeMethods.openBackend(byte[])' when mixing `RunWith(AndroidJUnit4::class)`

[david-allison]

A mix of JvmTest with and without the AndroidJUnit4 annotation produces flaky tests

Steps

Apply this patch & run tests on com.ichi2.anki.libanki

Subject: [PATCH] speed
---
Index: AnkiDroid/src/test/java/com/ichi2/libanki/FlagTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/FlagTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/FlagTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/FlagTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/FlagTest.kt	(date 1700607248378)
@@ -21,7 +21,6 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
-@RunWith(AndroidJUnit4::class)
 class FlagTest : JvmTest() {
     /*****************
      ** Flags        *
Index: AnkiDroid/src/test/java/com/ichi2/libanki/AbstractSchedTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/AbstractSchedTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/AbstractSchedTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/AbstractSchedTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/AbstractSchedTest.kt	(date 1700607248355)
@@ -15,7 +15,6 @@
  */
 package com.ichi2.libanki
 
-import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.ichi2.libanki.sched.Counts
 import com.ichi2.testutils.JvmTest
 import com.ichi2.utils.KotlinCleanup
@@ -23,7 +22,6 @@
 import org.hamcrest.Matchers.*
 import org.json.JSONArray
 import org.junit.Test
-import org.junit.runner.RunWith
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 
@@ -32,7 +30,6 @@
 @KotlinCleanup("is -> equalTo")
 @KotlinCleanup("reduce newlines in asserts")
 @KotlinCleanup("improve increaseAndAssertNewCountsIs")
-@RunWith(AndroidJUnit4::class)
 class AbstractSchedTest : JvmTest() {
     @Test
     fun ensureUndoCorrectCounts() {
Index: AnkiDroid/build.gradle
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/build.gradle b/AnkiDroid/build.gradle
--- a/AnkiDroid/build.gradle	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/build.gradle	(date 1700607248350)
@@ -388,6 +388,7 @@
     testImplementation("androidx.fragment:fragment-testing:$fragments_version")
     // in a JvmTest we need org.json.JSONObject to not be mocked
     testImplementation 'org.json:json:20220924'
+    testImplementation 'io.github.ivanshafran:shared-preferences-mock:1.2.4'
     // May need a resolution strategy for support libs to our versions
     androidTestImplementation "androidx.test.espresso:espresso-core:$espresso_version"
     androidTestImplementation("androidx.test.espresso:espresso-contrib:$espresso_version") {
Index: AnkiDroid/src/test/java/com/ichi2/testutils/JvmTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/testutils/JvmTest.kt b/AnkiDroid/src/test/java/com/ichi2/testutils/JvmTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/testutils/JvmTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/testutils/JvmTest.kt	(date 1700607248414)
@@ -18,6 +18,10 @@
 
 import android.annotation.SuppressLint
 import androidx.annotation.CallSuper
+import androidx.core.content.edit
+import com.github.ivanshafran.sharedpreferencesmock.SPMockBuilder
+import com.ichi2.anki.AnkiDroidApp
+import com.ichi2.anki.CollectionHelper
 import com.ichi2.anki.CollectionManager
 import com.ichi2.libanki.ChangeManager
 import com.ichi2.libanki.Collection
@@ -38,6 +42,7 @@
 import org.junit.Before
 import timber.log.Timber
 import timber.log.Timber.Forest.plant
+import java.nio.file.Files
 
 open class JvmTest {
     private fun maybeSetupBackend() {
@@ -57,6 +62,12 @@
     @Before
     @CallSuper
     open fun setUp() {
+        AnkiDroidApp.sharedPreferencesTestingOverride = SPMockBuilder().createSharedPreferences()
+        AnkiDroidApp.sharedPrefs().edit {
+            putString(CollectionHelper.PREF_COLLECTION_PATH, Files.createTempDirectory(
+                "AnkiDroid-JvmTest"
+            ).toFile().path)
+        }
         TimeManager.resetWith(MockTime(2020, 7, 7, 7, 0, 0, 0, 10))
 
         ChangeManager.clearSubscribers()
@@ -83,6 +94,7 @@
     @After
     @CallSuper
     open fun tearDown() {
+        AnkiDroidApp.sharedPreferencesTestingOverride = null
         try {
             // If you don't tear down the database you'll get unexpected IllegalStateExceptions related to connections
             col_?.close()
Index: AnkiDroid/src/test/java/com/ichi2/libanki/DecksTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/DecksTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/DecksTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/DecksTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/DecksTest.kt	(date 1700607248370)
@@ -30,7 +30,6 @@
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
-@RunWith(AndroidJUnit4::class)
 class DecksTest : JvmTest() {
     @Test
     fun test_remove() {
Index: AnkiDroid/src/test/java/com/ichi2/libanki/PythonExtensionsTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/PythonExtensionsTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/PythonExtensionsTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/PythonExtensionsTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/PythonExtensionsTest.kt	(date 1700607248400)
@@ -27,7 +27,6 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
-@RunWith(AndroidJUnit4::class)
 class PythonExtensionsTest {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/ModelTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/ModelTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/ModelTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/ModelTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/ModelTest.kt	(date 1700607248392)
@@ -37,7 +37,6 @@
     return " data-cloze=\"${data}\""
 }
 
-@RunWith(AndroidJUnit4::class)
 @KotlinCleanup("improve kotlin code where possible")
 class NotetypeTest : JvmTest() {
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/UtilsTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/UtilsTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/UtilsTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/UtilsTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/UtilsTest.kt	(date 1700607248411)
@@ -23,7 +23,6 @@
 import org.junit.runner.RunWith
 import java.util.*
 
-@RunWith(AndroidJUnit4::class)
 class UtilsTest {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/FinderTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/FinderTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/FinderTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/FinderTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/FinderTest.kt	(date 1700607248374)
@@ -36,7 +36,6 @@
 import timber.log.Timber
 import java.util.*
 
-@RunWith(AndroidJUnit4::class)
 class FinderTest : JvmTest() {
     @Test
     @Config(qualifiers = "en")
Index: AnkiDroid/src/test/java/com/ichi2/libanki/MathJaxClozeTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/MathJaxClozeTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/MathJaxClozeTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/MathJaxClozeTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/MathJaxClozeTest.kt	(date 1700607248382)
@@ -12,7 +12,6 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
-@RunWith(AndroidJUnit4::class)
 @KotlinCleanup("removeFormattingFromMathjax was imported to stop bug in Kotlin: java.lang.NoSuchFieldError: INSTANCE")
 @KotlinCleanup("add testing function returning c.models.byName(\"Cloze\")")
 class MathJaxClozeTest : JvmTest() {
Index: AnkiDroid/src/test/java/com/ichi2/libanki/CardTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/CardTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/CardTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/CardTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/CardTest.kt	(date 1700607248359)
@@ -31,7 +31,7 @@
 import java.util.*
 import kotlin.test.assertNotNull
 
-@RunWith(AndroidJUnit4::class)
+@RunWith(AndroidJUnit4::class) // nextDueTest: Short Date Format is different
 class CardTest : JvmTest() {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/TagsTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/TagsTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/TagsTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/TagsTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/TagsTest.kt	(date 1700607248407)
@@ -22,7 +22,6 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
-@RunWith(AndroidJUnit4::class)
 class TagsTest : JvmTest() {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/StorageRustTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/StorageRustTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/StorageRustTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/StorageRustTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/StorageRustTest.kt	(date 1700607248403)
@@ -24,7 +24,6 @@
 import org.junit.runner.RunWith
 import org.robolectric.annotation.Config
 
-@RunWith(AndroidJUnit4::class)
 class StorageRustTest : JvmTest() {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/ConfigTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/ConfigTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/ConfigTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/ConfigTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/ConfigTest.kt	(date 1700607248367)
@@ -26,8 +26,6 @@
 import org.junit.Test
 import org.junit.jupiter.api.assertThrows
 import org.junit.runner.RunWith
-
-@RunWith(AndroidJUnit4::class)
 class ConfigTest : JvmTest() {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/CollectionTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/CollectionTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/CollectionTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/CollectionTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/CollectionTest.kt	(date 1700607248363)
@@ -26,7 +26,7 @@
 import org.junit.runner.RunWith
 import java.util.*
 
-@RunWith(AndroidJUnit4::class)
+@RunWith(AndroidJUnit4::class) // test_timestamps: AnkiDroidApp.instance
 class CollectionTest : JvmTest() {
     @Test
     fun editClozeGenerateCardsInSameDeck() {
Index: AnkiDroid/src/test/java/com/ichi2/libanki/NoteWithColTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/NoteWithColTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/NoteWithColTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/NoteWithColTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/NoteWithColTest.kt	(date 1700607248395)
@@ -24,7 +24,6 @@
 import org.junit.runner.RunWith
 import org.robolectric.annotation.Config
 
-@RunWith(AndroidJUnit4::class)
 class NoteWithColTest : JvmTest() {
 
     @Test
Index: AnkiDroid/src/test/java/com/ichi2/libanki/MetaTest.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/AnkiDroid/src/test/java/com/ichi2/libanki/MetaTest.kt b/AnkiDroid/src/test/java/com/ichi2/libanki/MetaTest.kt
--- a/AnkiDroid/src/test/java/com/ichi2/libanki/MetaTest.kt	(revision 4ac94b14feb30004eb3d7f68cdb88f075b0fc459)
+++ b/AnkiDroid/src/test/java/com/ichi2/libanki/MetaTest.kt	(date 1700607248387)
@@ -22,7 +22,6 @@
 import org.junit.Test
 import org.junit.runner.RunWith
 
-@RunWith(AndroidJUnit4::class)
 class MetaTest : JvmTest() {
     @Test
     fun ensureDatabaseIsInMemory() {

Result

Flaky tests sometimes failing with

'byte[][] net.ankiweb.rsdroid.NativeMethods.openBackend(byte[])'
java.lang.UnsatisfiedLinkError: 'byte[][] net.ankiweb.rsdroid.NativeMethods.openBackend(byte[])'
	at net.ankiweb.rsdroid.NativeMethods.openBackend(Native Method)
	at net.ankiweb.rsdroid.Backend.<init>(Backend.kt:81)

This is not a failure to call RustBackendLoader.ensureSetup(), if ensureSetup() is forced to be called twice, it fails Native Library /private/var/folders/ym/nqynp93d4j74dpzw20sq4wq00000gn/T/librsdroid-b7f0b01dd98e063d7f3e09f8a0a0979aafe9dc0c.dylib already loaded in another classloader

Classloaders

There are two classloaders in play:

• jdk.internal.loader.ClassLoaders$AppClassLoader@14899482 (currentThread on JvmTest/ClassLoader.getSystemClassLoader())
• org.robolectric.internal.bytecode.SandboxClassLoader (currentThread on @RunWith(AndroidJUnit4::class))

Inside a JvmTest, if you use the non-default (SandboxClassLoader) to load RustBackendLoader:

• First test passes, second test fails with java.lang.UnsatisfiedLinkError: 'byte[][] ...

Inside an AndroidJUnitTest: if you use the non-default AppClassLoader:

• First test fails with java.lang.UnsatisfiedLinkError: 'byte[][] ...

Debug info

HEAD is 4ac94b14feb30004eb3d7f68cdb88f075b0fc459

Research

• [x] I have read the support page and am reporting a bug or enhancement request specific to AnkiDroid
• [x] I have checked the manual and the FAQ and could not find a solution to my issue
• [x] I have searched for similar existing issues here and on the user forum
• [x] (Optional) I have confirmed the issue is not resolved in the latest alpha release (instructions)

[david-allison]

One likely workaround would be to split the following into different modules:

• /test Pure Java
• /test Robolectric
• /androidTest

[dae]

I hit something similar to this in the past. From maybeSetupBackend():

            // We must make sure not to load the backend library into a test running outside
            // the Robolectric classloader, or subsequent Robolectric tests that run in this
            // process will be unable to make calls into the backend.

Changing forkEvery = 40 to forkEvery = 1 seems to fix it, but impacts performance. https://docs.gradle.org/current/userguide/jvm_test_suite_plugin.html is probably the path forward

[david-allison]

https://docs.gradle.org/current/userguide/jvm_test_suite_plugin.html is probably the path forward

Tried adding:

testing {
    suites {
        integrationTest(JvmTestSuite) {
            dependencies {
                implementation project()
            }

            targets {
                all {
                    testTask.configure {
                        shouldRunAfter(JvmTestSuite)
                    }
                }
            }
        }
    }
}

This creates a non-Android sourceset: integrationTest, which is ignored by Android Studio

Alternatives

• splitting into another module
  • Untested
• upgrading to JUnit5 for the specific files. Using Tags to exclude them
  • Can't run Jvm/Non-JVM at the same time within the IDE
• Using a custom TestRunner/Suite + @Ignore
  • Duplicates each JVM-only test in the Android Studio UI: listed under the Suite as passed, but listed again as ignored

[dae]

This is what ChatGPT suggested - I have not tried it myself:

plugins {
    id 'java'
}

testing {
    suites {
        robolectric(JvmTestSuite) {
            // Configure robolectric test suite specifics
        }
        javaUnit(JvmTestSuite) {
            // Configure java unit test suite specifics
        }
    }
}

sourceSets {
    main {
        java {
            srcDir 'src/main/java'
        }
    }
    robolectric {
        java {
            srcDir 'src/test/robolectric'
        }
    }
    javaUnit {
        java {
            srcDir 'src/test/javaunit'
        }
    }
}

testing.suites.robolectric {
    useJUnitJupiter()
    dependencies {
        implementation project.sourceSets.main.output
        implementation sourceSets.robolectric.output
        // Add your Robolectric-specific dependencies here
    }
}

testing.suites.javaUnit {
    useJUnitJupiter()
    dependencies {
        implementation project.sourceSets.main.output
        implementation sourceSets.javaUnit.output
        // Add your Java unit test-specific dependencies here
    }
}

Apparently after that, you would be able to do ./gradlew javaUnitTest, or robolectricTest, or just test to do them both.

[mikehardy]

As much as I'm a devotee of LudditeGPT the suggestion earlier to split tests, and the suggestion from our ML overlords seems like the right way to work around a different root classloader issue without getting so clever that we can't maintain it

[david-allison]

Non-Android source sets detected in ":Anki-Android":

Gradle source sets ignored: robolectric, javaUnit, main.

---

Unverified research: test/androidTest seem fairly heavily hardcoded: https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:build-system/gradle-core/src/main/java/com/android/build/gradle/internal/VariantManager.kt;l=690-736?q=setUpSourceSet&ss=android-studio%2Fplatform%2Ftools%2Fbase

[dae]

Ok, I think I get you - it's an IDE issue you're trying to work around, not a gradle one? Does AndroidStudio cope fine with a pure-Java module? If not, maybe JUnit4's categories could be used so that an upgrade to JUnit5 is not required?

[github-actions[bot]]

Hello 👋, this issue has been opened for more than 3 months with no activity on it. If the issue is still here, please keep in mind that we need community support and help to fix it! Just comment something like still searching for solutions and if you found one, please open a pull request! You have 7 days until this gets closed automatically