diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 696cc3f0b8..4a3f72a785 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -49,4 +49,4 @@ jobs:
         distribution: 'temurin'
         java-version: ${{ matrix.java }}
     - name: Build with Maven
-      run: ./mvnw -V --file pom.xml --no-transfer-progress -DtrimStackTrace=false -P-use-toolchains,docker
+      run: ./mvnw -V --file pom.xml --no-transfer-progress -DtrimStackTrace=false -Djunit.jupiter.execution.parallel.enabled=false -P-use-toolchains,docker
diff --git a/httpclient5-testing/pom.xml b/httpclient5-testing/pom.xml
index 84e1ef5bba..42176ccb5a 100644
--- a/httpclient5-testing/pom.xml
+++ b/httpclient5-testing/pom.xml
@@ -88,6 +88,11 @@
       <artifactId>junit-jupiter</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.junit.platform</groupId>
+      <artifactId>junit-platform-launcher</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.hamcrest</groupId>
       <artifactId>hamcrest</artifactId>
@@ -159,4 +164,4 @@
     </plugins>
   </reporting>
 
-</project>
\ No newline at end of file
+</project>
diff --git a/httpclient5/pom.xml b/httpclient5/pom.xml
index 37c924eb8a..561ca52cc4 100644
--- a/httpclient5/pom.xml
+++ b/httpclient5/pom.xml
@@ -57,6 +57,12 @@
       <artifactId>conscrypt-openjdk-uber</artifactId>
       <optional>true</optional>
     </dependency>
+    <dependency>
+      <groupId>org.apache.httpcomponents.core5</groupId>
+      <artifactId>httpcore5</artifactId>
+      <classifier>tests</classifier>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.apache.httpcomponents.core5</groupId>
       <artifactId>httpcore5-reactive</artifactId>
@@ -88,6 +94,11 @@
       <artifactId>junit-jupiter</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.junit.platform</groupId>
+      <artifactId>junit-platform-launcher</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.hamcrest</groupId>
       <artifactId>hamcrest</artifactId>
@@ -206,4 +217,4 @@
     </profile>
   </profiles>
 
-</project>
\ No newline at end of file
+</project>
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/ExecSupportTest.java b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/ExecSupportTest.java
index 88c5773538..0543f47ea0 100644
--- a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/ExecSupportTest.java
+++ b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/ExecSupportTest.java
@@ -28,7 +28,9 @@
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.parallel.Isolated;
 
+@Isolated
 class ExecSupportTest {
 
     @Test
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/auth/TestSystemDefaultCredentialsProvider.java b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/auth/TestSystemDefaultCredentialsProvider.java
index 2aec4041dd..ce71b055bd 100644
--- a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/auth/TestSystemDefaultCredentialsProvider.java
+++ b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/auth/TestSystemDefaultCredentialsProvider.java
@@ -40,12 +40,14 @@
 import org.apache.hc.client5.http.protocol.HttpClientContext;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.parallel.Isolated;
 import org.mockito.ArgumentMatchers;
 import org.mockito.Mockito;
 
 /**
  * Simple tests for {@link SystemDefaultCredentialsProvider}.
  */
+@Isolated
 class TestSystemDefaultCredentialsProvider {
 
     private final static String PROXY_PROTOCOL1 = "http";
diff --git a/pom.xml b/pom.xml
index 1a0d7291c6..ea11f3ef20 100644
--- a/pom.xml
+++ b/pom.xml
@@ -94,6 +94,12 @@
         <artifactId>httpcore5</artifactId>
         <version>${httpcore.version}</version>
       </dependency>
+      <dependency>
+        <groupId>org.apache.httpcomponents.core5</groupId>
+        <artifactId>httpcore5</artifactId>
+        <version>${httpcore.version}</version>
+        <classifier>tests</classifier>
+      </dependency>
       <dependency>
         <groupId>org.apache.httpcomponents.core5</groupId>
         <artifactId>httpcore5-h2</artifactId>