test: Revert back removed tests

Co-authored-by: Oleksandr Klymenko <[email protected]>
Signed-off-by: Oleksandr Klymenko <[email protected]>

Author: alxkm

spring-ai-client-chat/src/test/java/org/springframework/ai/chat/client/DefaultChatClientTests.java

@@ -1683,6 +1683,28 @@ void whenFunctionNameIsEmptyThenThrow() {
 			.build())).isInstanceOf(IllegalArgumentException.class).hasMessage("name cannot be null or empty");
 	}
 
+	@Test
+	@Disabled("This fails now as the FunctionToolCallback description is allowed to be empty")
+	void whenFunctionDescriptionIsNullThenThrow() {
+		ChatClient chatClient = new DefaultChatClientBuilder(mock(ChatModel.class)).build();
+		ChatClient.ChatClientRequestSpec spec = chatClient.prompt();
+		assertThatThrownBy(() -> spec.toolCallbacks(FunctionToolCallback.builder("name", input -> "hello")
+			.description(null)
+			.inputType(String.class)
+			.build())).isInstanceOf(IllegalArgumentException.class).hasMessage("Description must not be empty");
+	}
+
+	@Test
+	@Disabled("This fails now as the FunctionToolCallback description is allowed to be empty")
+	void whenFunctionDescriptionIsEmptyThenThrow() {
+		ChatClient chatClient = new DefaultChatClientBuilder(mock(ChatModel.class)).build();
+		ChatClient.ChatClientRequestSpec spec = chatClient.prompt();
+		assertThatThrownBy(() -> spec.toolCallbacks(
+				FunctionToolCallback.builder("name", input -> "hello").description("").inputType(String.class).build()))
+			.isInstanceOf(IllegalArgumentException.class)
+			.hasMessage("Description must not be empty");
+	}
+
 	@Test
 	void whenFunctionThenReturn() {
 		ChatClient chatClient = new DefaultChatClientBuilder(mock(ChatModel.class)).build();