better tests style

src/main/java/click/kamil/springstatemachineexporter/statemachine/KamilEnumStateMachineConfiguration.java

@@ -64,7 +64,6 @@ class KamilEnumStateMachineConfiguration extends StateMachineConfigurerAdapter<O
                 .and().withExternal().source(OrderStates.PAID2).event(OrderEvents.ABCD).action(new Action<OrderStates, OrderEvents>() {
                     @Override
                     public void execute(StateContext<OrderStates, OrderEvents> context) {
-                        ;
                     }
                 }).action(action2);
     }

src/test/java/click/kamil/springstatemachineexporter/ast/app/TransitionStateUtilsTest.java

@@ -7,7 +7,6 @@ import java.util.List;
 import java.util.Set;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 class TransitionStateUtilsTest {
 

src/test/java/click/kamil/springstatemachineexporter/ast/in/AstFileFinderTest.java

@@ -213,7 +213,7 @@ class AstFileFinderTest {
 
         // AST parser might still create a valid AST even with syntax errors
         // The result depends on how the parser handles the invalid syntax
-        assertThat(result).isNotNull();
+        assertThat(result).isTrue();
     }
 
     @Test