Feat: Add test case for find_matches

Slight find_matches rewrite to use Write trait.

Cargo.lock

@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "0.6.19"
@@ -52,6 +61,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.98"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e16d2d3311acee920a9eb8d33b8cbc1787ce4a264e85f964c2404b969bdcd487"
+
 [[package]]
 name = "clap"
 version = "4.5.39"
@@ -98,11 +113,37 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
 
+[[package]]
+name = "env_filter"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "186e05a59d4c50738528153b83b0b0194d3a29507dfec16eccd4b342903397d0"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.11.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13c863f0904021b108aa8b2f55046443e6b1ebde8fd4a15c399893aae4fa069f"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "env_filter",
+ "jiff",
+ "log",
+]
+
 [[package]]
 name = "grrs"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "clap",
+ "env_logger",
+ "log",
 ]
 
 [[package]]
@@ -117,12 +158,63 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "jiff"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a194df1107f33c79f4f93d02c80798520551949d59dfad22b6157048a88cca93"
+dependencies = [
+ "jiff-static",
+ "log",
+ "portable-atomic",
+ "portable-atomic-util",
+ "serde",
+]
+
+[[package]]
+name = "jiff-static"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c6e1db7ed32c6c71b759497fae34bf7933636f75a251b9e736555da426f6442"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "log"
+version = "0.4.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13dc2df351e3202783a1fe0d44375f7295ffb4049267b0f3018346dc122a1d94"
+
+[[package]]
+name = "memchr"
+version = "2.7.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
+
 [[package]]
 name = "once_cell_polyfill"
 version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a4895175b425cb1f87721b59f0f286c2092bd4af812243672510e1ac53e2e0ad"
 
+[[package]]
+name = "portable-atomic"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f84267b20a16ea918e43c6a88433c2d54fa145c92a811b5b047ccbe153674483"
+
+[[package]]
+name = "portable-atomic-util"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d8a2f0d8d040d7848a709caf78912debcc3f33ee4b3cac47d73d1e1069e83507"
+dependencies = [
+ "portable-atomic",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.95"
@@ -141,6 +233,55 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
+
+[[package]]
+name = "serde"
+version = "1.0.219"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f0e2c6ed6606019b4e29e69dbaba95b11854410e5347d525002456dbbb786b6"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.219"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b0276cf7f2c73365f7157c8123c21cd9a50fbbd844757af28ca1f5925fc2a00"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "strsim"
 version = "0.11.1"

Cargo.toml

@@ -4,4 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+anyhow = "1.0.98"
 clap = { version = "4.5.39", features = ["derive"] }
+env_logger = "0.11.8"
+log = "0.4.27"

src/main.rs

@@ -1,4 +1,6 @@
+use anyhow::{Context, Result};
 use clap::Parser;
+use log::info;
 
 // Search for a pattern in a file and display the lines that contain it.
 #[derive(Parser)]
@@ -7,14 +9,46 @@ struct Cli {
     path: std::path::PathBuf,
 }
 
-fn main() {
+fn main() -> Result<()> {
+    env_logger::init();
+    info!("starting up");
     let args = Cli::parse();
 
-    let content = std::fs::read_to_string(&args.path).expect("Could not read file.");
+    // let content = std::fs::read_to_string(&args.path).expect("Could not read file.");
 
+    let content = std::fs::read_to_string(&args.path)
+        .with_context(|| format!("could not read file `{}`.", args.path.display()))?;
+
+    find_matches(
+        content.as_str(),
+        args.pattern.as_str(),
+        &mut std::io::stdout(),
+    );
+
+    Ok(())
+}
+
+fn find_matches(content: &str, pattern: &str, mut writer: impl std::io::Write) {
     for line in content.lines() {
-        if line.contains(&args.pattern) {
+        if line.contains(pattern) {
-            println!("{}", line)
+            writeln!(writer, "{}", line);
         }
     }
 }
+
+#[test]
+fn find_a_match() {
+    let mut result = Vec::new();
+    find_matches("lorem ipsum\ndolar sit amet", "lorem", &mut result);
+    assert_eq!(result, b"lorem ipsum\n")
+}
+
+#[allow(dead_code)]
+fn answer() -> i32 {
+    return 42;
+}
+
+#[test]
+fn check_answer_validity() {
+    assert_eq!(answer(), 42);
+}