Skip C++ neo4j tests if C++ frontend is not enabled

cpg-neo4j/src/test/kotlin/de/fraunhofer/aisec/cpg_vis_neo4j/ApplicationTest.kt

@@ -60,6 +60,7 @@ fun createTranslationResult(file: String = "client.cpp"): Pair<Application, Tran
 class ApplicationTest {
 
     @Test
+    @SkipIfLanguageIsNotAvailable("de.fraunhofer.aisec.cpg.frontends.cxx.CPPLanguage")
     fun testSerializeCpgViaOGM() {
         val (application, translationResult) = createTranslationResult()
 
@@ -94,6 +95,7 @@ class ApplicationTest {
     }
 
     @Test
+    @SkipIfLanguageIsNotAvailable("de.fraunhofer.aisec.cpg.frontends.cxx.CPPLanguage")
     fun testExportToJson() {
         val (application, translationResult) = createTranslationResult()
         // 22 inferred functions, 1 inferred method, 2 inferred constructors, 11 regular functions

cpg-neo4j/src/test/kotlin/de/fraunhofer/aisec/cpg_vis_neo4j/Neo4JTest.kt

@@ -39,6 +39,7 @@ import org.junit.jupiter.api.Tag
 @Tag("integration")
 class Neo4JTest {
     @Test
+    @SkipIfLanguageIsNotAvailable("de.fraunhofer.aisec.cpg.frontends.cxx.CPPLanguage")
     fun testPush() {
         val (application, result) = createTranslationResult()
 
@@ -49,6 +50,7 @@ class Neo4JTest {
     }
 
     @Test
+    @SkipIfLanguageIsNotAvailable("de.fraunhofer.aisec.cpg.frontends.cxx.CPPLanguage")
     fun testPushVeryLong() {
         val (application, result) = createTranslationResult("very_long.cpp")
 
@@ -62,6 +64,7 @@ class Neo4JTest {
     }
 
     @Test
+    @SkipIfLanguageIsNotAvailable("de.fraunhofer.aisec.cpg.frontends.cxx.CPPLanguage")
     fun testPushConcepts() {
         val (application, result) = createTranslationResult()
 

cpg-neo4j/src/test/kotlin/de/fraunhofer/aisec/cpg_vis_neo4j/SkipIfLanguageIsNotAvailable.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2025, Fraunhofer AISEC. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *                    $$$$$$\  $$$$$$$\   $$$$$$\
+ *                   $$  __$$\ $$  __$$\ $$  __$$\
+ *                   $$ /  \__|$$ |  $$ |$$ /  \__|
+ *                   $$ |      $$$$$$$  |$$ |$$$$\
+ *                   $$ |      $$  ____/ $$ |\_$$ |
+ *                   $$ |  $$\ $$ |      $$ |  $$ |
+ *                   \$$$$$   |$$ |      \$$$$$   |
+ *                    \______/ \__|       \______/
+ *
+ */
+package de.fraunhofer.aisec.cpg_vis_neo4j
+
+import de.fraunhofer.aisec.cpg.frontends.Language
+import kotlin.reflect.full.createInstance
+import org.junit.jupiter.api.extension.ConditionEvaluationResult
+import org.junit.jupiter.api.extension.ExecutionCondition
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.api.extension.ExtensionContext
+
+/** This annotation can be used to skip a test if a certain language is not available. */
+@ExtendWith(LanguageAvailability::class)
+annotation class SkipIfLanguageIsNotAvailable(
+    /** The fully qualified name of the language that must be available. */
+    val language: String
+)
+
+/** This condition checks if a [Language] is available by trying to instantiate it. */
+class LanguageAvailability : ExecutionCondition {
+    override fun evaluateExecutionCondition(
+        context: ExtensionContext?
+    ): ConditionEvaluationResult? {
+        val annotation =
+            context?.element?.get()?.getAnnotation(SkipIfLanguageIsNotAvailable::class.java)
+
+        if (annotation == null) {
+            return ConditionEvaluationResult.enabled("No language annotation found")
+        }
+
+        try {
+            Class.forName(annotation.language).kotlin.createInstance() as? Language<*>
+        } catch (_: ClassNotFoundException) {
+            return ConditionEvaluationResult.disabled(
+                "Language ${annotation.language} is not available"
+            )
+        }
+
+        return ConditionEvaluationResult.enabled("Language ${annotation.language} is available")
+    }
+}