1// Copyright (c) 2018 The predicates-rs Project Developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9use std::borrow;
10use std::fmt;
11
12use crate::reflection;
13use crate::Predicate;
14
15/// Predicate that diffs two strings.
16///
17/// This is created by the `predicate::str::diff`.
18#[derive(Debug, Clone, PartialEq, Eq)]
19pub struct DifferencePredicate {
20 orig: borrow::Cow<'static, str>,
21}
22
23impl Predicate<str> for DifferencePredicate {
24 fn eval(&self, edit: &str) -> bool {
25 edit == self.orig
26 }
27
28 fn find_case<'a>(&'a self, expected: bool, variable: &str) -> Option<reflection::Case<'a>> {
29 let result = variable != self.orig;
30 if result == expected {
31 None
32 } else {
33 let palette = crate::Palette::current();
34 let orig: Vec<_> = self.orig.lines().map(|l| format!("{}\n", l)).collect();
35 let variable: Vec<_> = variable.lines().map(|l| format!("{}\n", l)).collect();
36 let diff = difflib::unified_diff(
37 &orig,
38 &variable,
39 "",
40 "",
41 &palette.expected.paint("orig").to_string(),
42 &palette.var.paint("var").to_string(),
43 0,
44 );
45 let mut diff = colorize_diff(diff, palette);
46 diff.insert(0, "\n".to_owned());
47
48 Some(
49 reflection::Case::new(Some(self), result).add_product(reflection::Product::new(
50 "diff",
51 itertools::join(diff.iter(), ""),
52 )),
53 )
54 }
55 }
56}
57
58impl reflection::PredicateReflection for DifferencePredicate {
59 fn parameters<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Parameter<'a>> + 'a> {
60 let params = vec![reflection::Parameter::new("original", &self.orig)];
61 Box::new(params.into_iter())
62 }
63}
64
65impl fmt::Display for DifferencePredicate {
66 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
67 let palette = crate::Palette::current();
68 write!(
69 f,
70 "{} {} {}",
71 palette.description.paint("diff"),
72 palette.expected.paint("original"),
73 palette.var.paint("var"),
74 )
75 }
76}
77
78/// Creates a new `Predicate` that diffs two strings.
79///
80/// # Examples
81///
82/// ```
83/// use predicates::prelude::*;
84///
85/// let predicate_fn = predicate::str::diff("Hello World");
86/// assert_eq!(true, predicate_fn.eval("Hello World"));
87/// assert!(predicate_fn.find_case(false, "Hello World").is_none());
88/// assert_eq!(false, predicate_fn.eval("Goodbye World"));
89/// assert!(predicate_fn.find_case(false, "Goodbye World").is_some());
90/// ```
91pub fn diff<S>(orig: S) -> DifferencePredicate
92where
93 S: Into<borrow::Cow<'static, str>>,
94{
95 DifferencePredicate { orig: orig.into() }
96}
97
98#[cfg(feature = "color")]
99fn colorize_diff(mut lines: Vec<String>, palette: crate::Palette) -> Vec<String> {
100 for (i, line) in lines.iter_mut().enumerate() {
101 match (i, line.as_bytes().get(0)) {
102 (0, _) => {
103 if let Some((prefix, body)) = line.split_once(' ') {
104 *line = format!("{} {}", palette.expected.paint(prefix), body);
105 }
106 }
107 (1, _) => {
108 if let Some((prefix, body)) = line.split_once(' ') {
109 *line = format!("{} {}", palette.var.paint(prefix), body);
110 }
111 }
112 (_, Some(b'-')) => {
113 let (prefix, body) = line.split_at(1);
114 *line = format!("{}{}", palette.expected.paint(prefix), body);
115 }
116 (_, Some(b'+')) => {
117 let (prefix, body) = line.split_at(1);
118 *line = format!("{}{}", palette.var.paint(prefix), body);
119 }
120 (_, Some(b'@')) => {
121 *line = format!("{}", palette.description.paint(&line));
122 }
123 _ => (),
124 }
125 }
126 lines
127}
128
129#[cfg(not(feature = "color"))]
130fn colorize_diff(lines: Vec<String>, _palette: crate::Palette) -> Vec<String> {
131 lines
132}
133