diff --git a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/assembly/AssemblyManagerCreateDockerTarArchiveTest.java b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/assembly/AssemblyManagerCreateDockerTarArchiveTest.java
index 8a3d4067a6..96ef9dad49 100644
--- a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/assembly/AssemblyManagerCreateDockerTarArchiveTest.java
+++ b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/assembly/AssemblyManagerCreateDockerTarArchiveTest.java
@@ -41,6 +41,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
+import static org.apache.commons.io.FilenameUtils.separatorsToSystem;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
@@ -105,8 +106,8 @@ void withoutDockerfile() throws IOException {
     assertBuildDirectoryFileTree("test-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "jkube-generated-layer-final-artifact",
-        "jkube-generated-layer-final-artifact/maven",
-        "jkube-generated-layer-final-artifact/maven/test-0.1.0.jar",
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven"),
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven/test-0.1.0.jar"),
         "maven"
     );
   }
@@ -136,8 +137,8 @@ void withoutDockerfileAndFinalCustomizer() throws IOException {
     assertBuildDirectoryFileTree("no-docker-file-and-customizer").containsExactlyInAnyOrder(
         "Dockerfile",
         "jkube-generated-layer-final-artifact",
-        "jkube-generated-layer-final-artifact/maven",
-        "jkube-generated-layer-final-artifact/maven/test-0.1.0.jar",
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven"),
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven/test-0.1.0.jar"),
         "maven");
     assertThat(customized).isTrue();
   }
@@ -166,8 +167,8 @@ void withoutDockerfileAndAlreadyExistingFileInAssemblyGetsOverwritten() throws I
     assertBuildDirectoryFileTree("modified-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "jkube-generated-layer-final-artifact",
-        "jkube-generated-layer-final-artifact/maven",
-        "jkube-generated-layer-final-artifact/maven/test-0.1.0.jar",
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven"),
+        separatorsToSystem("jkube-generated-layer-final-artifact/maven/test-0.1.0.jar"),
         "maven");
     assertThat(resolveDockerBuild("modified-image")
         .resolve("jkube-generated-layer-final-artifact").resolve("maven").resolve("test-0.1.0.jar"))
@@ -197,10 +198,10 @@ void withDockerfileInBaseDirectory() throws IOException {
     assertBuildDirectoryFileTree("test-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "maven",
-        "maven/Dockerfile",
-        "maven/test-0.1.0.jar",
-        "maven/target",
-        "maven/target/test-0.1.0.jar");
+        separatorsToSystem("maven/Dockerfile"),
+        separatorsToSystem("maven/test-0.1.0.jar"),
+        separatorsToSystem("maven/target"),
+        separatorsToSystem("maven/target/test-0.1.0.jar"));
   }
 
   @Test
@@ -238,11 +239,11 @@ void withDockerfileInBaseDirectoryAndAssemblyFile() throws IOException {
     assertBuildDirectoryFileTree("dockerfile-and-assembly-file").containsExactlyInAnyOrder(
         "Dockerfile",
         "maven",
-        "maven/Dockerfile",
-        "maven/test-0.1.0.jar",
-        "maven/extra-file-1.txt",
-        "maven/target",
-        "maven/target/test-0.1.0.jar");
+        separatorsToSystem("maven/Dockerfile"),
+        separatorsToSystem("maven/test-0.1.0.jar"),
+        separatorsToSystem("maven/extra-file-1.txt"),
+        separatorsToSystem("maven/target"),
+        separatorsToSystem("maven/target/test-0.1.0.jar"));
   }
 
   @Test
@@ -271,9 +272,9 @@ void withDockerfileInBaseDirectoryAndDockerinclude() throws IOException {
     assertBuildDirectoryFileTree("test-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "maven",
-        "maven/test-0.1.0.jar",
-        "maven/target",
-        "maven/target/ill-be-included.txt");
+        separatorsToSystem("maven/test-0.1.0.jar"),
+        separatorsToSystem("maven/target"),
+        separatorsToSystem("maven/target/ill-be-included.txt"));
   }
 
   @Test
@@ -302,11 +303,12 @@ void withDockerfileInBaseDirectoryAndDockerexclude() throws IOException {
     assertBuildDirectoryFileTree("test-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "maven",
-        "maven/Dockerfile",
-        "maven/test-0.1.0.jar",
-        "maven/target",
-        "maven/target/test-0.1.0.jar",
-        "maven/target/ill-be-included");
+        separatorsToSystem("maven/Dockerfile"),
+        separatorsToSystem("maven/test-0.1.0.jar"),
+        separatorsToSystem("maven/target"),
+        separatorsToSystem("maven/target/test-0.1.0.jar"),
+        separatorsToSystem("maven/target/ill-be-included")
+    );
   }
 
   @Test
@@ -335,11 +337,11 @@ void withDockerfileInBaseDirectoryAndDockerignore() throws IOException {
     assertBuildDirectoryFileTree("test-image").containsExactlyInAnyOrder(
         "Dockerfile",
         "maven",
-        "maven/Dockerfile",
-        "maven/test-0.1.0.jar",
-        "maven/target",
-        "maven/target/test-0.1.0.jar",
-        "maven/target/i-wont-be-ignored");
+        separatorsToSystem("maven/Dockerfile"),
+        separatorsToSystem("maven/test-0.1.0.jar"),
+        separatorsToSystem("maven/target"),
+        separatorsToSystem("maven/target/test-0.1.0.jar"),
+        separatorsToSystem("maven/target/i-wont-be-ignored"));
   }
 
   private void assertTargetHasDockerDirectories(String imageDirName) {
diff --git a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/auth/handler/OpenShiftRegistryAuthHandlerTest.java b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/auth/handler/OpenShiftRegistryAuthHandlerTest.java
index 7cbe3f2658..1885d0261b 100644
--- a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/auth/handler/OpenShiftRegistryAuthHandlerTest.java
+++ b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/auth/handler/OpenShiftRegistryAuthHandlerTest.java
@@ -20,6 +20,7 @@
 import java.nio.file.Path;
 import java.util.Base64;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Consumer;
 
 import com.fasterxml.jackson.core.type.TypeReference;
@@ -127,7 +128,7 @@ private void createOpenShiftConfig(File homeDir, String testConfig) {
       File kubeDir = new File(homeDir, ".kube");
       kubeDir.mkdirs();
       File config = new File(kubeDir, "config");
-      IOUtils.copy(getClass().getResourceAsStream(testConfig), new FileOutputStream(config));
+      Files.copy(new File(Objects.requireNonNull(getClass().getResource(testConfig)).getFile()).toPath(), config.toPath());
     } catch (IOException e) {
       throw new RuntimeException(e);
     }
diff --git a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/helper/DockerFileUtilTest.java b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/helper/DockerFileUtilTest.java
index 492b8f7932..39ac4cba53 100644
--- a/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/helper/DockerFileUtilTest.java
+++ b/jkube-kit/build/api/src/test/java/org/eclipse/jkube/kit/build/api/helper/DockerFileUtilTest.java
@@ -119,7 +119,7 @@ void interpolate_withNullFilter_shouldPickDefaultFilter() throws IOException {
         String result = DockerFileUtil.interpolate(givenDockerfile, properties, null);
 
         // Then
-        String[] lines = result.split("\n");
+        String[] lines = result.split(System.lineSeparator());
         assertThat(result).isNotNull();
         assertThat(lines).hasSize(2)
             .containsExactly("FROM openjdk:latest",
diff --git a/jkube-kit/common/src/test/java/org/eclipse/jkube/kit/common/assertj/ArchiveAssertions.java b/jkube-kit/common/src/test/java/org/eclipse/jkube/kit/common/assertj/ArchiveAssertions.java
index 229e83c260..f5884b23f5 100644
--- a/jkube-kit/common/src/test/java/org/eclipse/jkube/kit/common/assertj/ArchiveAssertions.java
+++ b/jkube-kit/common/src/test/java/org/eclipse/jkube/kit/common/assertj/ArchiveAssertions.java
@@ -38,6 +38,7 @@
 import org.assertj.core.error.ShouldBeEmpty;
 import org.assertj.core.internal.Failures;
 
+import static org.apache.commons.io.FilenameUtils.separatorsToSystem;
 import static org.assertj.core.error.ShouldBeEqualIgnoringCase.shouldBeEqual;
 
 public class ArchiveAssertions extends AbstractFileAssert<ArchiveAssertions> {
@@ -126,8 +127,8 @@ public ArchiveAssertions hasSameContentAsDirectory(File directory) throws IOExce
     final List<String> actualEntries = new ArrayList<>();
     processArchive(actual, (entry, tis) -> {
       // Remove last separator for directory entries -> Required for fileTree assertion
-      actualEntries.add(entry.isDirectory() ?
-          entry.getName().substring(0, entry.getName().length() - 1) : entry.getName());
+      actualEntries.add(separatorsToSystem(entry.isDirectory() ?
+          entry.getName().substring(0, entry.getName().length() - 1) : entry.getName()));
       final File expected = new File(directory, entry.getName());
       if (!expected.exists()) {
         throw failures.failure(info, new BasicErrorMessageFactory("%nExpecting archive <%s>%nnot to contain entry:%n <%s>%n",