Merge pull request #225 from dandavison/whitespace

Drop leading space, highlight empty lines, highlight whitespace errors

10 files changed, 490 insertions, 86 deletions

diff --git a/src/cli.rs b/src/cli.rs
index 52cbe0e7..ec45fffb 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -404,6 +404,22 @@ pub struct Opt {
     #[structopt(parse(from_os_str))]
     pub plus_file: Option<PathBuf>,
 
+    /// Style for removed empty line marker (used only if --minus-style has no background color)
+    #[structopt(
+        long = "--minus-empty-line-marker-style",
+        default_value = "normal auto"
+    )]
+    pub minus_empty_line_marker_style: String,
+
+    /// Style for added empty line marker (used only if --plus-style has no background color)
+    #[structopt(long = "--plus-empty-line-marker-style", default_value = "normal auto")]
+    pub plus_empty_line_marker_style: String,
+
+    /// Style for whitespace errors. Defaults to color.diff.whitespace if that is set in git
+    /// config, or else 'magenta reverse'.
+    #[structopt(long = "whitespace-error-style", default_value = "auto auto")]
+    pub whitespace_error_style: String,
+
     #[structopt(long = "minus-color")]
     /// Deprecated: use --minus-style='normal my_background_color'.
     pub deprecated_minus_background_color: Option<String>,
diff --git a/src/config.rs b/src/config.rs
index c5299e12..e05d7b8c 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -26,7 +26,7 @@ pub enum Width {
     Variable,
 }
 
-pub struct Config<'a> {
+pub struct Config {
     pub background_color_extends_to_terminal_width: bool,
     pub commit_style: Style,
     pub decorations_width: Width,
@@ -35,6 +35,7 @@ pub struct Config<'a> {
     pub file_removed_label: String,
     pub file_renamed_label: String,
     pub file_style: Style,
+    pub keep_plus_minus_markers: bool,
     pub hunk_header_style: Style,
     pub list_languages: bool,
     pub list_syntax_theme_names: bool,
@@ -43,8 +44,8 @@ pub struct Config<'a> {
     pub max_line_distance: f64,
     pub max_line_distance_for_naively_paired_lines: f64,
     pub minus_emph_style: Style,
+    pub minus_empty_line_marker_style: Style,
     pub minus_file: Option<PathBuf>,
-    pub minus_line_marker: &'a str,
     pub minus_non_emph_style: Style,
     pub minus_style: Style,
     pub navigate: bool,
@@ -58,8 +59,8 @@ pub struct Config<'a> {
     pub number_plus_style: Style,
     pub paging_mode: PagingMode,
     pub plus_emph_style: Style,
+    pub plus_empty_line_marker_style: Style,
     pub plus_file: Option<PathBuf>,
-    pub plus_line_marker: &'a str,
     pub plus_non_emph_style: Style,
     pub plus_style: Style,
     pub show_background_colors: bool,
@@ -71,10 +72,11 @@ pub struct Config<'a> {
     pub tab_width: usize,
     pub true_color: bool,
     pub tokenization_regex: Regex,
+    pub whitespace_error_style: Style,
     pub zero_style: Style,
 }
 
-impl<'a> Config<'a> {
+impl Config {
     pub fn from_args(args: &[&str], git_config: &mut Option<GitConfig>) -> Self {
         Self::from_arg_matches(cli::Opt::clap().get_matches_from(args), git_config)
     }
@@ -149,7 +151,7 @@ fn is_truecolor_terminal() -> bool {
         .unwrap_or(false)
 }
 
-impl<'a> From<cli::Opt> for Config<'a> {
+impl From<cli::Opt> for Config {
     fn from(opt: cli::Opt) -> Self {
         let assets = HighlightingAssets::new();
 
@@ -208,10 +210,13 @@ impl<'a> From<cli::Opt> for Config<'a> {
             minus_style,
             minus_emph_style,
             minus_non_emph_style,
+            minus_empty_line_marker_style,
             zero_style,
             plus_style,
             plus_emph_style,
             plus_non_emph_style,
+            plus_empty_line_marker_style,
+            whitespace_error_style,
         ) = make_hunk_styles(&opt, is_light_mode, true_color);
 
         let (commit_style, file_style, hunk_header_style) =
@@ -236,17 +241,6 @@ impl<'a> From<cli::Opt> for Config<'a> {
         };
         let syntax_dummy_theme = assets.theme_set.themes.values().next().unwrap().clone();
 
-        let minus_line_marker = if opt.keep_plus_minus_markers {
-            "-"
-        } else {
-            " "
-        };
-        let plus_line_marker = if opt.keep_plus_minus_markers {
-            "+"
-        } else {
-            " "
-        };
-
         let max_line_distance_for_naively_paired_lines =
             env::get_env_var("DELTA_EXPERIMENTAL_MAX_LINE_DISTANCE_FOR_NAIVELY_PAIRED_LINES")
                 .map(|s| s.parse::<f64>().unwrap_or(0.0))
@@ -271,6 +265,7 @@ impl<'a> From<cli::Opt> for Config<'a> {
             file_removed_label: opt.file_removed_label,
             file_renamed_label: opt.file_renamed_label,
             file_style,
+            keep_plus_minus_markers: opt.keep_plus_minus_markers,
             hunk_header_style,
             list_languages: opt.list_languages,
             list_syntax_theme_names: opt.list_syntax_theme_names,
@@ -279,8 +274,8 @@ impl<'a> From<cli::Opt> for Config<'a> {
             max_line_distance: opt.max_line_distance,
             max_line_distance_for_naively_paired_lines,
             minus_emph_style,
+            minus_empty_line_marker_style,
             minus_file: opt.minus_file.map(|s| s.clone()),
-            minus_line_marker,
             minus_non_emph_style,
             minus_style,
             navigate: opt.navigate,
@@ -294,8 +289,8 @@ impl<'a> From<cli::Opt> for Config<'a> {
             number_plus_style,
             paging_mode,
             plus_emph_style,
+            plus_empty_line_marker_style,
             plus_file: opt.plus_file.map(|s| s.clone()),
-            plus_line_marker,
             plus_non_emph_style,
             plus_style,
             show_background_colors: opt.show_background_colors,
@@ -307,6 +302,7 @@ impl<'a> From<cli::Opt> for Config<'a> {
             tab_width: opt.tab_width,
             tokenization_regex,
             true_color,
+            whitespace_error_style,
             zero_style,
         }
     }
@@ -316,7 +312,18 @@ fn make_hunk_styles<'a>(
     opt: &'a cli::Opt,
     is_light_mode: bool,
     true_color: bool,
-) -> (Style, Style, Style, Style, Style, Style, Style) {
+) -> (
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+    Style,
+) {
     let minus_style = Style::from_str(
         &opt.minus_style,
         None,
@@ -350,6 +357,20 @@ fn make_hunk_styles<'a>(
         false,
     );
 
+    // The style used to highlight a removed empty line when otherwise it would be invisible due to
+    // lack of background color in minus-style.
+    let minus_empty_line_marker_style = Style::from_str(
+        &opt.minus_empty_line_marker_style,
+        None,
+        Some(color::get_minus_background_color_default(
+            is_light_mode,
+            true_color,
+        )),
+        None,
+        true_color,
+        false,
+    );
+
     let zero_style = Style::from_str(&opt.zero_style, None, None, None, true_color, false);
 
     let plus_style = Style::from_str(
@@ -385,14 +406,40 @@ fn make_hunk_styles<'a>(
         false,
     );
 
+    // The style used to highlight an added empty line when otherwise it would be invisible due to
+    // lack of background color in plus-style.
+    let plus_empty_line_marker_style = Style::from_str(
+        &opt.plus_empty_line_marker_style,
+        None,
+        Some(color::get_plus_background_color_default(
+            is_light_mode,
+            true_color,
+        )),
+        None,
+        true_color,
+        false,
+    );
+
+    let whitespace_error_style = Style::from_str(
+        &opt.whitespace_error_style,
+        None,
+        None,
+        None,
+        true_color,
+        false,
+    );
+
     (
         minus_style,
         minus_emph_style,
         minus_non_emph_style,
+        minus_empty_line_marker_style,
         zero_style,
         plus_style,
         plus_emph_style,
         plus_non_emph_style,
+        plus_empty_line_marker_style,
+        whitespace_error_style,
     )
 }
 
diff --git a/src/delta.rs b/src/delta.rs
index b498bd0a..366520ec 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -405,6 +405,7 @@ fn handle_hunk_header_line(
                 "",
                 config.null_style,
                 config.null_style,
+                None,
                 Some(false),
             );
             painter.output_buffer.pop(); // trim newline
@@ -467,7 +468,11 @@ fn handle_hunk_line(
         }
         Some(' ') => {
             let state = State::HunkZero;
-            let prefix = if line.is_empty() { "" } else { &line[..1] };
+            let prefix = if config.keep_plus_minus_markers && !line.is_empty() {
+                &line[..1]
+            } else {
+                ""
+            };
             painter.paint_buffered_lines();
             let lines = vec![prepare(&line, true, config)];
             let syntax_style_sections = Painter::get_syntax_style_sections_for_lines(
@@ -491,6 +496,7 @@ fn handle_hunk_line(
                 config.zero_style,
                 config.zero_style,
                 None,
+                None,
             );
             painter.minus_line_number += 1;
             painter.plus_line_number += 1;
@@ -520,12 +526,22 @@ fn prepare(line: &str, append_newline: bool, config: &Config) -> String {
     if !line.is_empty() {
         let mut line = line.graphemes(true);
 
-        // The first column contains a -/+/space character, added by git. We substitute it for a
-        // space now, so that it is not present during syntax highlighting, and substitute again
-        // when emitting the line.
+        // The first column contains a -/+/space character, added by git. If we are retaining them
+        // (--keep-plus-minus-markers), then we substitute it for a space now, so that it is not
+        // present during syntax highlighting, and reinstate it when emitting the line in
+        // Painter::paint_lines. If we not retaining them, then we drop it now, and
+        // Painter::paint_lines doesn't inject anything.
         line.next();
-
-        format!(" {}{}", expand_tabs(line, config.tab_width), terminator)
+        format!(
+            "{}{}{}",
+            if config.keep_plus_minus_markers {
+                " "
+            } else {
+                ""
+            },
+            expand_tabs(line, config.tab_width),
+            terminator
+        )
     } else {
         terminator.to_string()
     }
diff --git a/src/paint.rs b/src/paint.rs
index d1505c74..f946853c 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -14,6 +14,8 @@ use crate::paint::superimpose_style_sections::superimpose_style_sections;
 use crate::style::Style;
 
 pub const ANSI_CSI_CLEAR_TO_EOL: &str = "\x1b[0K";
+pub const ANSI_CSI_CLEAR_TO_BOL: &str = "\x1b[1K";
+pub const ANSI_CSI_CURSOR_BACK_1: &str = "\x1b[1D";
 pub const ANSI_SGR_RESET: &str = "\x1b[0m";
 
 pub struct Painter<'a> {
@@ -22,7 +24,7 @@ pub struct Painter<'a> {
     pub writer: &'a mut dyn Write,
     pub syntax: &'a SyntaxReference,
     pub highlighter: HighlightLines<'a>,
-    pub config: &'a config::Config<'a>,
+    pub config: &'a config::Config,
     pub output_buffer: String,
     pub minus_line_number: usize,
     pub plus_line_number: usize,
@@ -96,9 +98,14 @@ impl<'a> Painter<'a> {
                 minus_line_numbers,
                 &mut self.output_buffer,
                 self.config,
-                self.config.minus_line_marker,
+                if self.config.keep_plus_minus_markers {
+                    "-"
+                } else {
+                    ""
+                },
                 self.config.minus_style,
                 self.config.minus_non_emph_style,
+                Some(self.config.minus_empty_line_marker_style),
                 None,
             );
         }
@@ -109,9 +116,14 @@ impl<'a> Painter<'a> {
                 plus_line_numbers,
                 &mut self.output_buffer,
                 self.config,
-                self.config.plus_line_marker,
+                if self.config.keep_plus_minus_markers {
+                    "+"
+                } else {
+                    ""
+                },
                 self.config.plus_style,
                 self.config.plus_non_emph_style,
+                Some(self.config.plus_empty_line_marker_style),
                 None,
             );
         }
@@ -130,6 +142,7 @@ impl<'a> Painter<'a> {
         prefix: &str,
         style: Style,          // style for right fill if line contains no emph sections
         non_emph_style: Style, // style for right fill if line contains emph sections
+        empty_line_style: Option<Style>, // a style with background color to highlight an empty line
         background_color_extends_to_terminal_width: Option<bool>,
     ) {
         // There's some unfortunate hackery going on here for two reasons:
@@ -204,19 +217,14 @@ impl<'a> Painter<'a> {
                     ansi_strings.push(section_style.ansi_term_style.paint(text));
                 }
             }
-            // Set style for the right-fill.
-            let mut have_background_for_right_fill = false;
-            if non_emph_style.ansi_term_style.background.is_some() {
+            let right_fill_background_color = non_emph_style.has_background_color()
+                && background_color_extends_to_terminal_width
+                    .unwrap_or(config.background_color_extends_to_terminal_width);
+            if right_fill_background_color {
                 ansi_strings.push(non_emph_style.ansi_term_style.paint(""));
-                have_background_for_right_fill = true;
             }
             let line = &mut ansi_term::ANSIStrings(&ansi_strings).to_string();
-            let background_color_extends_to_terminal_width =
-                match background_color_extends_to_terminal_width {
-                    Some(boolean) => boolean,
-                    None => config.background_color_extends_to_terminal_width,
-                };
-            if background_color_extends_to_terminal_width && have_background_for_right_fill {
+            if right_fill_background_color {
                 // HACK: How to properly incorporate the ANSI_CSI_CLEAR_TO_EOL into ansi_strings?
                 if line
                     .to_lowercase()
@@ -227,6 +235,18 @@ impl<'a> Painter<'a> {
                 output_buffer.push_str(&line);
                 output_buffer.push_str(ANSI_CSI_CLEAR_TO_EOL);
                 output_buffer.push_str(ANSI_SGR_RESET);
+            } else if line.is_empty() {
+                if let Some(empty_line_style) = empty_line_style {
+                    output_buffer.push_str(
+                        &empty_line_style
+                            .ansi_term_style
+                            .paint(format!(
+                                "{}{}",
+                                ANSI_CSI_CLEAR_TO_BOL, ANSI_CSI_CURSOR_BACK_1
+                            ))
+                            .to_string(),
+                    );
+                }
             } else {
                 output_buffer.push_str(&line);
             }
@@ -304,13 +324,17 @@ impl<'a> Painter<'a> {
         } else {
             None
         };
-        Self::update_styles(&mut diff_sections.0, minus_non_emph_style);
+        Self::update_styles(&mut diff_sections.0, None, minus_non_emph_style);
         let plus_non_emph_style = if config.plus_non_emph_style != config.plus_emph_style {
             Some(config.plus_non_emph_style)
         } else {
             None
         };
-        Self::update_styles(&mut diff_sections.1, plus_non_emph_style);
+        Self::update_styles(
+            &mut diff_sections.1,
+            Some(config.whitespace_error_style),
+            plus_non_emph_style,
+        );
         diff_sections
     }
 
@@ -320,15 +344,31 @@ impl<'a> Painter<'a> {
     ///    inferred edit operations and so, if there is a special non-emph style that is
     ///    distinct from the default style, then it should be used for the non-emph style
     ///    sections.
-    fn update_styles(style_sections: &mut Vec<Vec<(Style, &str)>>, non_emph_style: Option<Style>) {
+    /// 2. If the line constitutes a whitespace error, then the whitespace error style
+    ///    should be applied to the added material.
+    fn update_styles(
+        style_sections: &mut Vec<Vec<(Style, &str)>>,
+        whitespace_error_style: Option<Style>,
+        non_emph_style: Option<Style>,
+    ) {
         for line_sections in style_sections {
             let line_has_emph_and_non_emph_sections =
                 style_sections_contain_more_than_one_style(line_sections);
             let should_update_non_emph_styles =
                 non_emph_style.is_some() && line_has_emph_and_non_emph_sections;
+            let is_whitespace_error =
+                whitespace_error_style.is_some() && is_whitespace_error(line_sections);
             for section in line_sections.iter_mut() {
-                // Update the style if this is a non-emph section that needs updating.
-                if should_update_non_emph_styles && !section.0.is_emph {
+                // If the line as a whole constitutes a whitespace error then highlight this
+                // section if either (a) it is an emph section, or (b) the line lacks any
+                // emph/non-emph distinction.
+                if is_whitespace_error
+                    && (section.0.is_emph || !line_has_emph_and_non_emph_sections)
+                {
+                    *section = (whitespace_error_style.unwrap(), section.1);
+                }
+                // Otherwise, update the style if this is a non-emph section that needs updating.
+                else if should_update_non_emph_styles && !section.0.is_emph {
                     *section = (non_emph_style.unwrap(), section.1);
                 }
             }
@@ -351,6 +391,20 @@ fn style_sections_contain_more_than_one_style(sections: &Vec<(Style, &str)>) ->
     }
 }
 
+lazy_static! {
+    static ref NON_WHITESPACE_REGEX: Regex = Regex::new(r"\S").unwrap();
+}
+
+/// True iff the line represented by `sections` constitutes a whitespace error.
+// TODO: Git recognizes blank lines at end of file (blank-at-eof) as a whitespace error but delta
+// does not yet.
+// https://git-scm.com/docs/git-config#Documentation/git-config.txt-corewhitespace
+fn is_whitespace_error(sections: &Vec<(Style, &str)>) -> bool {
+    !sections
+        .iter()
+        .any(|(_, s)| NON_WHITESPACE_REGEX.is_match(s))
+}
+
 mod superimpose_style_sections {
     use syntect::highlighting::Style as SyntectStyle;
 
diff --git a/src/preset.rs b/src/preset.rs
index 6ce912c8..7dd13207 100644
--- a/src/preset.rs
+++ b/src/preset.rs
@@ -536,6 +536,81 @@ mod tests {
         remove_file(git_config_path).unwrap();
     }
 
+    #[test]
+    fn test_whitespace_error_style() {
+        let git_config_contents = b"
+[color \"diff\"]
+    whitespace = yellow dim ul magenta
+";
+        let git_config_path = "delta__test_whitespace_error_style.gitconfig";
+
+        // Git config disabled: hard-coded delta default wins
+        assert_eq!(
+            make_config(&[], None, None).whitespace_error_style,
+            make_style("magenta reverse")
+        );
+
+        // Unspecified by user: color.diff.whitespace wins
+        assert_eq!(
+            make_config(&[], Some(git_config_contents), Some(git_config_path))
+                .whitespace_error_style,
+            make_style("yellow dim ul magenta")
+        );
+
+        // Command line argument wins
+        assert_eq!(
+            make_config(
+                &["--whitespace-error-style", "red reverse"],
+                Some(git_config_contents),
+                Some(git_config_path)
+            )
+            .whitespace_error_style,
+            make_style("reverse red")
+        );
+
+        let git_config_contents = b"
+[color \"diff\"]
+    whitespace = yellow dim ul magenta
+
+[delta]
+    whitespace-error-style = blue reverse
+
+[delta \"my-whitespace-error-style-preset\"]
+    whitespace-error-style = green reverse
+";
+
+        // Command line argument wins
+        assert_eq!(
+            make_config(
+                &["--whitespace-error-style", "red reverse"],
+                Some(git_config_contents),
+                Some(git_config_path)
+            )
+            .whitespace_error_style,
+            make_style("reverse red")
+        );
+
+        // No command line argument; main [delta] section wins
+        assert_eq!(
+            make_config(&[], Some(git_config_contents), Some(git_config_path))
+                .whitespace_error_style,
+            make_style("blue reverse")
+        );
+
+        // No command line argument; preset section wins
+        assert_eq!(
+            make_config(
+                &["--presets", "my-whitespace-error-style-preset"],
+                Some(git_config_contents),
+                Some(git_config_path)
+            )
+            .whitespace_error_style,
+            make_style("reverse green")
+        );
+
+        remove_file(git_config_path).unwrap();
+    }
+
     fn make_style(s: &str) -> Style {
         _make_style(s, false)
     }
@@ -559,11 +634,11 @@ mod tests {
         GitConfig::from_path(&path)
     }
 
-    fn make_config<'a>(
+    fn make_config(
         args: &[&str],
         git_config_contents: Option<&[u8]>,
         path: Option<&str>,
-    ) -> config::Config<'a> {
+    ) -> config::Config {
         let args: Vec<&str> = itertools::chain(
             &["/dev/null", "/dev/null", "--24-bit-color", "always"],
             args,
diff --git a/src/set_options.rs b/src/set_options.rs
index fe5705c4..b6d8c0ae 100644
--- a/src/set_options.rs
+++ b/src/set_options.rs
@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use structopt::clap;
 
 use crate::cli;
+use crate::config;
 use crate::git_config::{self, GitConfigGet};
 use crate::preset::{self, GetValueFunctionFromBuiltinPreset};
 
@@ -161,6 +162,17 @@ pub fn set_options(
     if opt.no_gitconfig {
         return;
     }
+    // Handle options which default to an arbitrary git config value.
+    // TODO: incorporate this logic into the set_options macro.
+    if !config::user_supplied_option("whitespace-error-style", arg_matches) {
+        opt.whitespace_error_style = if let Some(git_config) = git_config {
+            git_config.get::<String>("color.diff.whitespace")
+        } else {
+            None
+        }
+        .unwrap_or_else(|| "magenta reverse".to_string())
+    }
+
     set_options!(
         [
             // --presets must be set first
@@ -188,6 +200,7 @@ pub fn set_options(
             // dynamically to the value of the former.
             ("minus-style", String, minus_style),
             ("minus-emph-style", String, minus_emph_style),
+            ("minus-empty-line-marker-style", String, minus_empty_line_marker_style),
             ("minus-non-emph-style", String, minus_non_emph_style),
             ("navigate", bool, navigate),
             ("number", bool, show_line_numbers),
@@ -206,10 +219,12 @@ pub fn set_options(
             // dynamically to the value of the former.
             ("plus-style", String, plus_style),
             ("plus-emph-style", String, plus_emph_style),
+            ("plus-empty-line-marker-style", String, plus_empty_line_marker_style),
             ("plus-non-emph-style", String, plus_non_emph_style),
             ("syntax_theme", Option<String>, syntax_theme),
             ("tabs", usize, tab_width),
             ("true-color", String, true_color),
+            ("whitespace-error-style", String, whitespace_error_style),
             ("width", Option<String>, width),
             ("word-diff-regex", String, tokenization_regex),
             ("zero-style", String, zero_style)
diff --git a/src/style.rs b/src/style.rs
index 6b11725f..7e7bea35 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -49,6 +49,14 @@ impl Style {
         }
     }
 
+    pub fn has_background_color(&self) -> bool {
+        if self.ansi_term_style.is_reverse {
+            self.ansi_term_style.foreground.is_some()
+        } else {
+            self.ansi_term_style.background.is_some()
+        }
+    }
+
     /// Construct Style from style and decoration-style strings supplied on command line, together
     /// with defaults. A style string is a space-separated string containing 0, 1, or 2 colors
     /// (foreground and then background) and an arbitrary number of style attributes. See `delta
diff --git a/src/tests/ansi_test_utils.rs b/src/tests/ansi_test_utils.rs
index 7d0ccf36..1b4a8c82 100644
--- a/src/tests/ansi_test_utils.rs
+++ b/src/tests/ansi_test_utils.rs
@@ -14,14 +14,31 @@ pub mod ansi_test_utils {
         expected_style: &str,
         config: &Config,
     ) {
-        _assert_line_has_style(
+        assert!(_line_has_style(
             output,
             line_number,
             expected_prefix,
             expected_style,
             config,
             false,
-        );
+        ));
+    }
+
+    pub fn assert_line_does_not_have_style(
+        output: &str,
+        line_number: usize,
+        expected_prefix: &str,
+        expected_style: &str,
+        config: &Config,
+    ) {
+        assert!(!_line_has_style(
+            output,
+            line_number,
+            expected_prefix,
+            expected_style,
+            config,
+            false,
+        ));
     }
 
     pub fn assert_line_has_4_bit_color_style(
@@ -31,14 +48,14 @@ pub mod ansi_test_utils {
         expected_style: &str,
         config: &Config,
     ) {
-        _assert_line_has_style(
+        assert!(_line_has_style(
             output,
             line_number,
             expected_prefix,
             expected_style,
             config,
             true,
-        );
+        ));
     }
 
     pub fn assert_line_has_no_color(output: &str, line_number: usize, expected_prefix: &str) {
@@ -114,18 +131,19 @@ pub mod ansi_test_utils {
             config.null_style,
             config.null_style,
             None,
+            None,
         );
         output_buffer
     }
 
-    fn _assert_line_has_style(
+    fn _line_has_style(
         output: &str,
         line_number: usize,
         expected_prefix: &str,
         expected_style: &str,
         config: &Config,
         _4_bit_color: bool,
-    ) {
+    ) -> bool {
         let line = output.lines().nth(line_number).unwrap();
         assert!(strip_ansi_codes(line).starts_with(expected_prefix));
         let mut style = Style::from_str(expected_style, None, None, None, config.true_color, false);
@@ -135,7 +153,7 @@ pub mod ansi_test_utils {
                 .foreground
                 .map(ansi_term_fixed_foreground_to_4_bit_color);
         }
-        assert!(line.starts_with(&style.ansi_term_style.prefix().to_string()))
+        line.starts_with(&style.ansi_term_style.prefix().to_string())
     }
 
     fn ansi_term_fixed_foreground_to_4_bit_color(color: ansi_term::Color) -> ansi_term::Color {
diff --git a/src/tests/integration_test_utils.rs b/src/tests/integration_test_utils.rs
index 01f08a4f..0259e25d 100644
--- a/src/tests/integration_test_utils.rs
+++ b/src/tests/integration_test_utils.rs
@@ -8,7 +8,7 @@ pub mod integration_test_utils {
     use crate::config;
     use crate::delta::delta;
 
-    pub fn make_config<'a>(_args: &[&str]) -> config::Config<'a> {
+    pub fn make_config(_args: &[&str]) -> config::Config {
         // FIXME: should not be necessary
         let (dummy_minus_file, dummy_plus_file) = ("/dev/null", "/