Feat: Add integration test for file not exist.

Cargo.lock

@@ -67,6 +67,39 @@ version = "1.0.98"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e16d2d3311acee920a9eb8d33b8cbc1787ce4a264e85f964c2404b969bdcd487"
 
+[[package]]
+name = "assert_cmd"
+version = "2.0.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bd389a4b2970a01282ee455294913c0a43724daedcd1a24c3eb0ec1c1320b66"
+dependencies = [
+ "anstyle",
+ "bstr",
+ "doc-comment",
+ "libc",
+ "predicates",
+ "predicates-core",
+ "predicates-tree",
+ "wait-timeout",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
+
+[[package]]
+name = "bstr"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "234113d19d0d7d613b40e86fb654acf958910802bcceab913a4f9e7cda03b1a4"
+dependencies = [
+ "memchr",
+ "regex-automata",
+ "serde",
+]
+
 [[package]]
 name = "clap"
 version = "4.5.39"
@@ -113,6 +146,18 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"
 
+[[package]]
+name = "difflib"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6184e33543162437515c2e2b48714794e37845ec9851711914eec9d308f6ebe8"
+
+[[package]]
+name = "doc-comment"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fea41bba32d969b513997752735605054bc0dfa92b4c56bf1189f2e174be7a10"
+
 [[package]]
 name = "env_filter"
 version = "0.1.3"
@@ -136,14 +181,25 @@ dependencies = [
  "log",
 ]
 
+[[package]]
+name = "float-cmp"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b09cf3155332e944990140d967ff5eceb70df778b34f77d8075db46e4704e6d8"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "grrs"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "assert_cmd",
  "clap",
  "env_logger",
  "log",
+ "predicates",
 ]
 
 [[package]]
@@ -182,6 +238,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "libc"
+version = "0.2.172"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d750af042f7ef4f724306de029d18836c26c1765a54a6a3f094cbd23a7267ffa"
+
 [[package]]
 name = "log"
 version = "0.4.27"
@@ -194,6 +256,21 @@ version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
+[[package]]
+name = "normalize-line-endings"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61807f77802ff30975e01f4f071c8ba10c022052f98b3294119f3e615d13e5be"
+
+[[package]]
+name = "num-traits"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "once_cell_polyfill"
 version = "1.70.1"
@@ -215,6 +292,36 @@ dependencies = [
  "portable-atomic",
 ]
 
+[[package]]
+name = "predicates"
+version = "3.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a5d19ee57562043d37e82899fade9a22ebab7be9cef5026b07fda9cdd4293573"
+dependencies = [
+ "anstyle",
+ "difflib",
+ "float-cmp",
+ "normalize-line-endings",
+ "predicates-core",
+ "regex",
+]
+
+[[package]]
+name = "predicates-core"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "727e462b119fe9c93fd0eb1429a5f7647394014cf3c04ab2c0350eeb09095ffa"
+
+[[package]]
+name = "predicates-tree"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72dd2d6d381dfb73a193c7fca536518d7caee39fc8503f74e7dc0be0531b425c"
+dependencies = [
+ "predicates-core",
+ "termtree",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.95"
@@ -299,6 +406,12 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "termtree"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f50febec83f5ee1df3015341d8bd429f2d1cc62bcba7ea2076759d315084683"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.18"
@@ -311,6 +424,15 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ac3b126d3914f9849036f826e054cbabdc8519970b8998ddaf3b5bd3c65f11"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.59.0"

Cargo.toml

@@ -8,3 +8,7 @@ anyhow = "1.0.98"
 clap = { version = "4.5.39", features = ["derive"] }
 env_logger = "0.11.8"
 log = "0.4.27"
+
+[dev-dependencies]
+assert_cmd = "2.0.17"
+predicates = "3.1.3"

src/lib.rs

@@ -0,0 +1,18 @@
+use anyhow::Result;
+
+pub fn find_matches(content: &str, pattern: &str, mut writer: impl std::io::Write) -> Result<()> {
+    for line in content.lines() {
+        if line.contains(pattern) {
+            writeln!(writer, "{}", line)?;
+        }
+    }
+    Ok(())
+}
+
+#[test]
+fn find_a_match() -> Result<(), Box<dyn std::error::Error>> {
+    let mut result = Vec::new();
+    find_matches("lorem ipsum\ndolar sit amet", "lorem", &mut result)?;
+    assert_eq!(result, b"lorem ipsum\n");
+    Ok(())
+}

src/main.rs

@@ -14,35 +14,18 @@ fn main() -> Result<()> {
     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)
         .with_context(|| format!("could not read file `{}`.", args.path.display()))?;
 
-    find_matches(
+    grrs::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(pattern) {
-            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;

tests/cli.rs

@@ -0,0 +1,15 @@
+use assert_cmd::prelude::*; // Add methods on commands
+use predicates::prelude::*; // Used for writing assertions
+use std::process::Command; // Run programs
+
+#[test]
+fn file_doesnt_exist() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin("grrs")?;
+
+    cmd.arg("foobar").arg("test/file/doesnt/exist");
+    cmd.assert()
+        .failure()
+        .stderr(predicate::str::contains("could not read file"));
+
+    Ok(())
+}