Use assertThatCode with lambda to test getDiagnostics doesn't throw

- Import assertThatCode from assertj
- Replace isEmpty() assertion with doesNotThrowAnyException()
- Specifically test that getDiagnostics call doesn't throw NPE

Co-authored-by: nixel2007 <[email protected]>

Author: Copilot

src/test/java/com/github/_1c_syntax/bsl/languageserver/diagnostics/UselessTernaryOperatorDiagnosticTest.java

@@ -29,6 +29,7 @@
 import java.util.List;
 
 import static com.github._1c_syntax.bsl.languageserver.util.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
 
 class UselessTernaryOperatorDiagnosticTest extends AbstractDiagnosticTest<UselessTernaryOperatorDiagnostic> {
 
@@ -89,9 +90,8 @@ void testMalformedTernaryOperatorDoesNotThrowNPE() {
     // Пример из issue: Return ?(table.Count() = 1, undefined, );
     var documentContext = getDocumentContext("UselessTernaryOperatorDiagnosticMalformed");
 
-    List<Diagnostic> diagnostics = getDiagnostics(documentContext);
-    
-    assertThat(diagnostics).isEmpty();
+    assertThatCode(() -> getDiagnostics(documentContext))
+      .doesNotThrowAnyException();
   }
 
 }