From 6d95cd79c40d82d26f2ca887494d01e8a7e90d6e Mon Sep 17 00:00:00 2001
From: laniakea64 <laniakea64@users.noreply.github.com>
Date: Wed, 24 Jan 2024 23:33:33 -0500
Subject: [PATCH] tests: drop colordiff dependency, perform diff internally in
 test runner

---
 .github/workflows/build.yaml |  5 ----
 README.md                    |  1 -
 tests/Cargo.lock             |  7 +++++
 tests/Cargo.toml             |  1 +
 tests/src/main.rs            | 53 ++++++++++++++++++++----------------
 5 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 53b64f1..bf0b524 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -37,11 +37,6 @@ jobs:
       run: |
         rustup component add clippy rustfmt
 
-    - name: Install dependencies
-      run: |
-        sudo apt-get update
-        sudo apt-get install colordiff
-
     - name: Info
       run: |
         rustup --version
diff --git a/README.md b/README.md
index 8ba5b85..e600892 100644
--- a/README.md
+++ b/README.md
@@ -68,7 +68,6 @@ surprised if I close your PR while pushing your authored commit directly to main
 ### Prerequisites
 
 * just (of course, lol)
-* [colordiff](https://www.colordiff.org/)
 * Rust ([simple/recommended installation instructions](https://www.rust-lang.org/tools/install); for detailed and alternative installation instructions see [here](https://forge.rust-lang.org/infra/other-installation-methods.html))
 
 Run `just deps` to install the cargo dev dependencies, which right now is only
diff --git a/tests/Cargo.lock b/tests/Cargo.lock
index e134fe6..04dad0b 100644
--- a/tests/Cargo.lock
+++ b/tests/Cargo.lock
@@ -737,6 +737,12 @@ dependencies = [
  "stable_deref_trait",
 ]
 
+[[package]]
+name = "similar"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32fea41aca09ee824cc9724996433064c89f7777e60762749a4170a14abbfa21"
+
 [[package]]
 name = "siphasher"
 version = "0.3.11"
@@ -845,6 +851,7 @@ dependencies = [
  "scraper",
  "serde",
  "serde_json",
+ "similar",
  "tempfile",
  "wait-timeout",
 ]
diff --git a/tests/Cargo.toml b/tests/Cargo.toml
index 716756f..ba8912c 100644
--- a/tests/Cargo.toml
+++ b/tests/Cargo.toml
@@ -18,5 +18,6 @@ rayon        = "1.8.1"
 scraper      = ">=0.18.1"
 serde        = { version = "1.0.195", features = ["derive"] }
 serde_json   = "1.0.111"
+similar      = "2.4.0"
 tempfile     = "3.9.0"
 wait-timeout = "0.2.0"
diff --git a/tests/src/main.rs b/tests/src/main.rs
index fb9ed41..5883357 100644
--- a/tests/src/main.rs
+++ b/tests/src/main.rs
@@ -10,7 +10,6 @@ use std::{
   fs,
   io::{self, ErrorKind},
   path::{Path, PathBuf},
-  process::Command,
   sync::{
     atomic::{AtomicU64, Ordering::Relaxed},
     Arc,
@@ -119,37 +118,43 @@ fn _main() -> io::Result<()> {
       continue;
     }
 
-    let diff_output_result = Command::new("colordiff")
-      .arg("--unified")
-      .args(["--label", "output"])
-      .arg(output)
-      .args(["--label", "expected"])
-      .arg(expected)
-      .output();
-
-    let diff_output = match diff_output_result {
-      Ok(o) => o,
-      Err(e) => {
-        eprintln!("Could not run colordiff: attempt failed with \"{e}\"\nIs colordiff installed and available executable on $PATH ?");
-        return Err(e);
-      }
-    };
-
     if interrupted.load(Relaxed) {
       return Err(io::Error::new(ErrorKind::Interrupted, "interrupted!"));
     }
 
-    if diff_output.status.success() {
+    let output = fs::read_to_string(output)?;
+    let expected = fs::read_to_string(expected)?;
+
+    let diff = format!(
+      "{}",
+      similar::TextDiff::from_lines(&output, &expected)
+        .unified_diff()
+        .header("output", "expected")
+    );
+    if diff.is_empty() {
       eprintln!("ok");
       passed += 1;
     } else {
-      if diff_output.status.code() == Some(2) {
-        eprintln!("syntax highlighting mismatch:");
-      } else {
-        eprintln!("diff failed:");
+      eprintln!("syntax highlighting mismatch:");
+      for line in diff.lines() {
+        if line.starts_with(' ') {
+          eprintln!("{}", line);
+          continue;
+        }
+        let color = if line.starts_with('+') {
+          "0;32"
+        } else if line.starts_with('-') {
+          "0;31"
+        } else if line.starts_with('@') {
+          "0;36"
+        } else {
+          return Err(io::Error::new(
+            ErrorKind::Other,
+            format!("no defined color for line: {:?}", line),
+          ));
+        };
+        eprintln!("\x1B[{}m{}\x1B[0m", color, line);
       }
-      eprint!("{}", String::from_utf8_lossy(&diff_output.stdout));
-      eprint!("{}", String::from_utf8_lossy(&diff_output.stderr));
     }
   }