Rewrite module test in kotlin

okio/src/jvmIntegrationTest/java/module-info.java

@@ -1,4 +1,5 @@
 open module okio.test.integration {
   requires okio;
   requires junit;
+  requires kotlin.stdlib;
 }

okio/src/jvmIntegrationTest/kotlin/okio/test/integration/ModuleTest.kt

@@ -0,0 +1,19 @@
+package okio.test.integration
+
+import okio.FileSystem
+import org.junit.Assert.*
+import org.junit.*
+
+class ModuleTest {
+  @Test
+  fun testModule() {
+    // test okio.test.integration is modular
+    assertTrue(ModuleTest::class.java.module.isNamed)
+    assertEquals(ModuleTest::class.java.module.name, "okio.test.integration")
+    assertFalse(ModuleTest::class.java.module.descriptor.isAutomatic)
+    // test okio is modular
+    assertTrue(FileSystem::class.java.module.isNamed)
+    assertEquals(FileSystem::class.java.module.name, "okio")
+    assertFalse(FileSystem::class.java.module.descriptor.isAutomatic)
+  }
+}