1 files changed, 11 insertions, 5 deletions
diff --git a/core/test-api/src/main/kotlin/testApi/logger/TestLogger.kt b/core/test-api/src/main/kotlin/testApi/logger/TestLogger.kt
index 0bc66a2b..e70200a7 100644
--- a/core/test-api/src/main/kotlin/testApi/logger/TestLogger.kt
+++ b/core/test-api/src/main/kotlin/testApi/logger/TestLogger.kt
@@ -1,24 +1,28 @@
 package org.jetbrains.dokka.testApi.logger
 
 import org.jetbrains.dokka.utilities.DokkaLogger
+import java.util.Collections
 
+/*
+ * Even in tests it be used in a concurrent environment, so needs to be thread safe
+ */
 class TestLogger(private val logger: DokkaLogger) : DokkaLogger {
     override var warningsCount: Int by logger::warningsCount
     override var errorsCount: Int by logger::errorsCount
 
-    private var _debugMessages = mutableListOf<String>()
+    private var _debugMessages = synchronizedMutableListOf<String>()
     val debugMessages: List<String> get() = _debugMessages.toList()
 
-    private var _infoMessages = mutableListOf<String>()
+    private var _infoMessages = synchronizedMutableListOf<String>()
     val infoMessages: List<String> get() = _infoMessages.toList()
 
-    private var _progressMessages = mutableListOf<String>()
+    private var _progressMessages = synchronizedMutableListOf<String>()
     val progressMessages: List<String> get() = _progressMessages.toList()
 
-    private var _warnMessages = mutableListOf<String>()
+    private var _warnMessages = synchronizedMutableListOf<String>()
     val warnMessages: List<String> get() = _warnMessages.toList()
 
-    private var _errorMessages = mutableListOf<String>()
+    private var _errorMessages = synchronizedMutableListOf<String>()
     val errorMessages: List<String> get() = _errorMessages.toList()
 
     override fun debug(message: String) {
@@ -45,4 +49,6 @@ class TestLogger(private val logger: DokkaLogger) : DokkaLogger {
         _errorMessages.add(message)
         logger.error(message)
     }
+
+    private fun <T> synchronizedMutableListOf(): MutableList<T> = Collections.synchronizedList(mutableListOf())
 }