diff --git a/pmd-core/src/test/java/net/sourceforge/pmd/processor/GlobalListenerTest.java b/pmd-core/src/test/java/net/sourceforge/pmd/processor/GlobalListenerTest.java
index 82ebbc4777..0cfb4e5f51 100644
--- a/pmd-core/src/test/java/net/sourceforge/pmd/processor/GlobalListenerTest.java
+++ b/pmd-core/src/test/java/net/sourceforge/pmd/processor/GlobalListenerTest.java
@@ -124,7 +124,7 @@ class GlobalListenerTest {
         PMDConfiguration config = new PMDConfiguration();
         config.setAnalysisCache(new NoopAnalysisCache());
         config.setIgnoreIncrementalAnalysis(true);
-        config.setThreads(1);
+        config.setThreads(0); // no multithreading for this test
         return config;
     }
 
diff --git a/pmd-core/src/test/java/net/sourceforge/pmd/processor/PmdRunnableTest.java b/pmd-core/src/test/java/net/sourceforge/pmd/processor/PmdRunnableTest.java
index 47f9afc689..2bb2804e24 100644
--- a/pmd-core/src/test/java/net/sourceforge/pmd/processor/PmdRunnableTest.java
+++ b/pmd-core/src/test/java/net/sourceforge/pmd/processor/PmdRunnableTest.java
@@ -65,8 +65,8 @@ class PmdRunnableTest {
         reporter = mock(MessageReporter.class);
         configuration.setReporter(reporter);
         // exceptions thrown on a worker thread are not thrown by the main thread,
-        // so this test only makes sense with one thread
-        configuration.setThreads(1);
+        // so this test only makes sense without separate threads
+        configuration.setThreads(0);
     }
 
 
diff --git a/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt b/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
index 211c5de605..594bd8f16e 100644
--- a/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
+++ b/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
@@ -233,7 +233,7 @@ abstract class BaseParsingHelper<Self : BaseParsingHelper<Self, T>, T : RootNode
             suppressMarker = params.suppressMarker
             forceLanguageVersion = defaultVersion
             isIgnoreIncrementalAnalysis = true
-            threads = 1
+            threads = 0 // don't use separate threads for rule execution
         }
 
         return PmdAnalysis.create(config).use { pmd ->
diff --git a/pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java b/pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java
index 1185d26c74..52d6982576 100644
--- a/pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java
+++ b/pmd-test/src/main/java/net/sourceforge/pmd/testframework/RuleTst.java
@@ -226,7 +226,7 @@ public abstract class RuleTst {
         PMDConfiguration configuration = new PMDConfiguration();
         configuration.setIgnoreIncrementalAnalysis(true);
         configuration.setDefaultLanguageVersion(languageVersion);
-        configuration.setThreads(1);
+        configuration.setThreads(0); // don't use separate threads
         configuration.prependAuxClasspath(".");
 
         try (PmdAnalysis pmd = PmdAnalysis.create(configuration)) {