diff --git a/build.gradle.kts b/build.gradle.kts
index ae4cf541..2a2a5f8f 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -104,7 +104,7 @@ tasks.test {
 testing {
     suites {
         // Separate test suite for module testing
-        val testModular by registering(JvmTestSuite::class) {
+        val testJavaModule by registering(JvmTestSuite::class) {
             dependencies {
                 implementation(project)
             }
@@ -116,7 +116,7 @@ testing {
 if (JavaVersion.current().isJava9Compatible) {
     tasks.check {
         @Suppress("UnstableApiUsage")
-        dependsOn(testing.suites.named("testModular"))
+        dependsOn(testing.suites.named("testJavaModule"))
     }
 }
 
diff --git a/src/main/java-9/module-info.java b/src/main/java-9/module-info.java
index b2dbf69e..93bc2312 100644
--- a/src/main/java-9/module-info.java
+++ b/src/main/java-9/module-info.java
@@ -1,5 +1,22 @@
+/*
+ * Copyright © 2018-today Peter M. Stahl pemistahl@gmail.com
+ *
+ * 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 expressed or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 module com.github.pemistahl.lingua {
     exports com.github.pemistahl.lingua.api;
+    exports com.github.pemistahl.lingua.api.io;
 
     requires kotlin.stdlib;
 
diff --git a/src/testJavaModule/java/module-info.java b/src/testJavaModule/java/module-info.java
new file mode 100644
index 00000000..02b757ac
--- /dev/null
+++ b/src/testJavaModule/java/module-info.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright © 2018-today Peter M. Stahl pemistahl@gmail.com
+ *
+ * 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 expressed or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Open complete module for reflection to allow JUnit to access the packages
+open module test {
+    requires com.github.pemistahl.lingua;
+
+    requires org.junit.jupiter.api;
+}
diff --git a/src/testJavaModule/java/test/LinguaTest.java b/src/testJavaModule/java/test/LinguaTest.java
new file mode 100644
index 00000000..b6cb21b3
--- /dev/null
+++ b/src/testJavaModule/java/test/LinguaTest.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright © 2018-today Peter M. Stahl pemistahl@gmail.com
+ *
+ * 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 expressed or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package test;
+
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.io.TempDir;
+
+import com.github.pemistahl.lingua.api.Language;
+import com.github.pemistahl.lingua.api.LanguageDetector;
+import com.github.pemistahl.lingua.api.LanguageDetectorBuilder;
+import com.github.pemistahl.lingua.api.io.LanguageModelFilesWriter;
+
+import static java.util.stream.Collectors.toList;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.condition.OS.WINDOWS;
+
+import static com.github.pemistahl.lingua.api.Language.ENGLISH;
+import static com.github.pemistahl.lingua.api.Language.FRENCH;
+import static com.github.pemistahl.lingua.api.Language.SPANISH;
+
+/**
+ * Tests basic Lingua functionality. The main purpose of this test is to verify that the
+ * packages can be accessed from a different module and that Lingua specifies all required
+ * modules and can be used successfully.
+ */
+class LinguaTest {
+    @Test
+    void testDetector() {
+        LanguageDetector detector = LanguageDetectorBuilder.fromLanguages(ENGLISH, FRENCH, SPANISH).build();
+        Language detectedLanguage = detector.detectLanguageOf("languages are awesome");
+        assertEquals(ENGLISH, detectedLanguage);
+    }
+
+    @Test
+    @DisabledOnOs(WINDOWS) // TempDir cannot be deleted on Windows
+    void testLanguageModelFilesWriter(@TempDir Path outputDirectoryPath) throws Exception {
+        Path inputFilePath = Files.createTempFile(null, null);
+
+        LanguageModelFilesWriter.createAndWriteLanguageModelFiles(
+            inputFilePath,
+            StandardCharsets.UTF_8,
+            outputDirectoryPath,
+            ENGLISH,
+            "\\p{L}&&\\p{IsLatin}"
+        );
+
+        List<Path> filesList = Files.list(outputDirectoryPath).collect(toList());
+
+        assertEquals(5, filesList.size());
+
+        inputFilePath.toFile().delete();
+    }
+}
diff --git a/src/testModular/java/module-info.java b/src/testModular/java/module-info.java
deleted file mode 100644
index 2069c996..00000000
--- a/src/testModular/java/module-info.java
+++ /dev/null
@@ -1,6 +0,0 @@
-// Open complete module for reflection to allow JUnit to access the packages
-open module test {
-    requires com.github.pemistahl.lingua;
-
-    requires org.junit.jupiter.api;
-}
diff --git a/src/testModular/java/test/LinguaTest.java b/src/testModular/java/test/LinguaTest.java
deleted file mode 100644
index f06c9fda..00000000
--- a/src/testModular/java/test/LinguaTest.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package test;
-
-import com.github.pemistahl.lingua.api.*;
-import org.junit.jupiter.api.Test;
-
-import static com.github.pemistahl.lingua.api.Language.*;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-/**
- * Tests basic Lingua functionality. The main purpose of this test is to verify that the
- * packages can be accessed from a different module and that Lingua specifies all required
- * modules and can be used successfully.
- */
-class LinguaTest {
-    @Test
-    void test() {
-        LanguageDetector detector = LanguageDetectorBuilder.fromLanguages(ENGLISH, FRENCH, GERMAN, SPANISH).build();
-        Language detectedLanguage = detector.detectLanguageOf("languages are awesome");
-        assertEquals(ENGLISH, detectedLanguage);
-    }
-}