add section about operating system specific tests

content/doc/developer/testing/index.adoc

@@ -246,6 +246,48 @@ To recreate the same configuration from a test method, you can do the following:
 In order to test parts of your plugin, you may want certain files to exist in the build workspace, or that Jenkins is configured in a certain way.
 This section covers various ways to achieve this using the Jenkins Test Harness.
 
+=== Operating System Awareness
+
+Sometimes it ios necessary to adjust the testcase depending on the operating system.
+This can be the choice of Batch or Shell commands.
+The following example shows how to make use of `Functions.isWindows()` to create different code depending on the operating system:
+
+[source,java]
+----
+import hudson.Functions;
+import hudson.model.FreeStyleProject;
+import hudson.tasks.BatchFile;
+import hudson.tasks.Shell;
+import org.jvnet.hudson.test.JenkinsRule;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class MyPluginTest {
+
+    @Rule
+    public JenkinsRule j = new JenkinsRule();
+
+    @Test
+    public void testOnAllSystems() throws Exception {
+        FreeStyleProject project = j.createFreeStyleProject();
+        if(Functions.isWindows()) {
+            project.getBuildersList().add(new BatchFile("echo ahoy > log.log"));
+        } else {
+            project.getBuildersList().add(new Shell("echo ahoy > log.log"));
+        }
+        j.buildAndAssertSuccess(project);
+    }
+}
+----
+
+If you just want to disable a test on Windows systems you can make use of `assumeFalse()` in combination with `Functions.isWindows()`:
+
+`assumeFalse("TODO: Implement this test on Windows", Functions.isWindows());`
+
+The following Test will only be executed if it is not executed under windows.
+
+Be aware, that in general, we encourage to also test functionality under windows!
+
 ==== Customizing the Build Workspace