Add an example test without an after text block

src/test/java/com/yourorg/NoGuavaListsNewArrayListTest.java

@@ -155,4 +155,24 @@ class Test {
           )
         );
     }
+
+    // Often you want to make sure no changes are made when the target state is already achieved.
+    // To do so only passs in a before state and no after state to the rewriteRun method SourceSpecs.
+    @Test
+    void noChangeNecessary() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.ArrayList;
+              import java.util.Collections;
+              import java.util.List;
+                            
+              class Test {
+                  List<Integer> cardinalsWorldSeries = Collections.unmodifiableList(new ArrayList<>());
+              }
+              """
+          )
+        );
+    }
 }