pub fn write_diff(
writer: &mut dyn std::fmt::Write,
expected: &crate::Data,
actual: &crate::Data,
expected_name: Option<&dyn std::fmt::Display>,
actual_name: Option<&dyn std::fmt::Display>,
palette: crate::report::Palette,
) -> Result<(), std::fmt::Error> {
#[allow(unused_mut)]
let mut rendered = false;
#[cfg(feature = "diff")]
if let (Some(expected), Some(actual)) = (expected.as_str(), actual.as_str()) {
write_diff_inner(
writer,
expected,
actual,
expected_name,
actual_name,
palette,
)?;
rendered = true;
}
if !rendered {
if let Some(expected_name) = expected_name {
writeln!(writer, "{} {}:", expected_name, palette.info("(expected)"))?;
} else {
writeln!(writer, "{}:", palette.info("Expected"))?;
}
writeln!(writer, "{}", palette.info(&expected))?;
if let Some(actual_name) = actual_name {
writeln!(writer, "{} {}:", actual_name, palette.error("(actual)"))?;
} else {
writeln!(writer, "{}:", palette.error("Actual"))?;
}
writeln!(writer, "{}", palette.error(&actual))?;
}
Ok(())
}
#[cfg(feature = "diff")]
fn write_diff_inner(
writer: &mut dyn std::fmt::Write,
expected: &str,
actual: &str,
expected_name: Option<&dyn std::fmt::Display>,
actual_name: Option<&dyn std::fmt::Display>,
palette: crate::report::Palette,
) -> Result<(), std::fmt::Error> {
let changes = similar::TextDiff::configure()
.algorithm(similar::Algorithm::Patience)
.timeout(std::time::Duration::from_millis(500))
.newline_terminated(false)
.diff_lines(expected, actual);
writeln!(writer)?;
if let Some(expected_name) = expected_name {
writeln!(
writer,
"{}",
palette.info(format_args!("--- {} (expected)", expected_name))
)?;
} else {
writeln!(writer, "{}", palette.info(format_args!("--- Expected")))?;
}
if let Some(actual_name) = actual_name {
writeln!(
writer,
"{}",
palette.error(format_args!("+++ {} (actual)", actual_name))
)?;
} else {
writeln!(writer, "{}", palette.error(format_args!("+++ Actual")))?;
}
for op in changes.ops() {
for change in changes.iter_inline_changes(op) {
match change.tag() {
similar::ChangeTag::Insert => {
write_change(writer, change, "+", palette.actual, palette.error, palette)?;
}
similar::ChangeTag::Delete => {
write_change(writer, change, "-", palette.expected, palette.info, palette)?;
}
similar::ChangeTag::Equal => {
write_change(writer, change, " ", palette.hint, palette.hint, palette)?;
}
}
}
}
Ok(())
}
#[cfg(feature = "diff")]
fn write_change(
writer: &mut dyn std::fmt::Write,
change: similar::InlineChange<str>,
sign: &str,
em_style: crate::report::Style,
style: crate::report::Style,
palette: crate::report::Palette,
) -> Result<(), std::fmt::Error> {
if let Some(index) = change.old_index() {
write!(writer, "{:>4} ", palette.hint(index + 1),)?;
} else {
write!(writer, "{:>4} ", " ",)?;
}
if let Some(index) = change.new_index() {
write!(writer, "{:>4} ", palette.hint(index + 1),)?;
} else {
write!(writer, "{:>4} ", " ",)?;
}
write!(writer, "{} ", style.paint(sign))?;
for &(emphasized, change) in change.values() {
let cur_style = if emphasized { em_style } else { style };
write!(writer, "{}", cur_style.paint(change))?;
}
if change.missing_newline() {
writeln!(writer, "{}", em_style.paint("∅"))?;
}
Ok(())
}
#[cfg(test)]
mod test {
use super::*;
#[cfg(feature = "diff")]
#[test]
fn diff_eq() {
let expected = "Hello\nWorld\n";
let expected_name = "A";
let actual = "Hello\nWorld\n";
let actual_name = "B";
let palette = crate::report::Palette::never();
let mut actual_diff = String::new();
write_diff_inner(
&mut actual_diff,
expected,
actual,
Some(&expected_name),
Some(&actual_name),
palette,
)
.unwrap();
let expected_diff = "
--- A (expected)
+++ B (actual)
1 1 Hello
2 2 World
";
assert_eq!(expected_diff, actual_diff);
}
#[cfg(feature = "diff")]
#[test]
fn diff_ne_line_missing() {
let expected = "Hello\nWorld\n";
let expected_name = "A";
let actual = "Hello\n";
let actual_name = "B";
let palette = crate::report::Palette::never();
let mut actual_diff = String::new();
write_diff_inner(
&mut actual_diff,
expected,
actual,
Some(&expected_name),
Some(&actual_name),
palette,
)
.unwrap();
let expected_diff = "
--- A (expected)
+++ B (actual)
1 1 Hello
2 - World
";
assert_eq!(expected_diff, actual_diff);
}
#[cfg(feature = "diff")]
#[test]
fn diff_eq_trailing_extra_newline() {
let expected = "Hello\nWorld";
let expected_name = "A";
let actual = "Hello\nWorld\n";
let actual_name = "B";
let palette = crate::report::Palette::never();
let mut actual_diff = String::new();
write_diff_inner(
&mut actual_diff,
expected,
actual,
Some(&expected_name),
Some(&actual_name),
palette,
)
.unwrap();
let expected_diff = "
--- A (expected)
+++ B (actual)
1 1 Hello
2 - World∅
2 + World
";
assert_eq!(expected_diff, actual_diff);
}
#[cfg(feature = "diff")]
#[test]
fn diff_eq_trailing_newline_missing() {
let expected = "Hello\nWorld\n";
let expected_name = "A";
let actual = "Hello\nWorld";
let actual_name = "B";
let palette = crate::report::Palette::never();
let mut actual_diff = String::new();
write_diff_inner(
&mut actual_diff,
expected,
actual,
Some(&expected_name),
Some(&actual_name),
palette,
)
.unwrap();
let expected_diff = "
--- A (expected)
+++ B (actual)
1 1 Hello
2 - World
2 + World∅
";
assert_eq!(expected_diff, actual_diff);
}
}