### Question:
MyTextDocumentService implements TextDocumentService, EventObserver<RunAnalysisEvent> { @Override public void didSave(DidSaveTextDocumentParams params) { LOG.info("Document saved..."); } @Inject @Builder  MyTextDocumentService(
      Communications communications,
      LanguageEngineFacade engine,
      Formations formations,
      Completions completions,
      Occurrences occurrences,
      DataBusBroker dataBus,
      CodeActions actions); @Override CompletableFuture<Either<List<CompletionItem>, CompletionList>> completion(
      CompletionParams params); @Override CompletableFuture<CompletionItem> resolveCompletionItem(CompletionItem unresolved); @Override CompletableFuture<List<? extends Location>> definition(
      TextDocumentPositionParams position); @Override CompletableFuture<List<? extends Location>> references(ReferenceParams params); @Override CompletableFuture<List<? extends DocumentHighlight>> documentHighlight(
      TextDocumentPositionParams position); @Override CompletableFuture<List<? extends TextEdit>> formatting(DocumentFormattingParams params); @Override CompletableFuture<List<Either<Command, CodeAction>>> codeAction(CodeActionParams params); @Override void didOpen(DidOpenTextDocumentParams params); @Override void didChange(DidChangeTextDocumentParams params); @Override void didClose(DidCloseTextDocumentParams params); @Override void didSave(DidSaveTextDocumentParams params); @Override void observerCallback(@Nonnull RunAnalysisEvent event); @Override CompletableFuture<List<Either<SymbolInformation, DocumentSymbol>>> documentSymbol(DocumentSymbolParams params);  }### Answer:
@Test void testDidSave() { TextDocumentIdentifier saveDocumentIdentifier = new TextDocumentIdentifier(DOCUMENT_URI); DidSaveTextDocumentParams saveDocumentParams = new DidSaveTextDocumentParams(saveDocumentIdentifier); service.didOpen( new DidOpenTextDocumentParams( new TextDocumentItem(DOCUMENT_URI, LANGUAGE, 1, TEXT_EXAMPLE))); service.didSave(saveDocumentParams); assertTrue(closeGetter(service).containsKey(DOCUMENT_URI)); }