diff options
Diffstat (limited to 'tests/test_display.rs')
-rw-r--r-- | tests/test_display.rs | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/tests/test_display.rs b/tests/test_display.rs index 949d9ed..99ce2fd 100644 --- a/tests/test_display.rs +++ b/tests/test_display.rs @@ -1,6 +1,4 @@ -#![deny(clippy::all, clippy::pedantic)] - -use std::fmt::Display; +use std::fmt::{self, Display}; use thiserror::Error; fn assert<T: Display>(expected: &str, value: T) { @@ -144,6 +142,35 @@ fn test_match() { } #[test] +fn test_nested_display() { + // Same behavior as the one in `test_match`, but without String allocations. + #[derive(Error, Debug)] + #[error("{}", { + struct Msg<'a>(&'a String, &'a Option<usize>); + impl<'a> Display for Msg<'a> { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + match self.1 { + Some(n) => write!(formatter, "error occurred with {}", n), + None => write!(formatter, "there was an empty error"), + }?; + write!(formatter, ": {}", self.0) + } + } + Msg(.0, .1) + })] + struct Error(String, Option<usize>); + + assert( + "error occurred with 1: ...", + Error("...".to_owned(), Some(1)), + ); + assert( + "there was an empty error: ...", + Error("...".to_owned(), None), + ); +} + +#[test] fn test_void() { #[allow(clippy::empty_enum)] #[derive(Error, Debug)] |