feat(xatu): set CLI exit statuses

src/xatu/BUILD

@@ -41,6 +41,17 @@ rust_test(
     ],
 )
 
+sh_test(
+    name = "xatu_cli_test",
+    srcs = ["xatu_cli_test.sh"],
+    data = [
+        ":xatu",
+        "testdata/clean.nix",
+        "testdata/invalid.nix",
+        "testdata/lint_findings.nix",
+    ],
+)
+
 rust_binary(
     name = "xatu",
     crate_name = "xatu_cli",

src/xatu/xatu_cli_test.sh

@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+xatu="$TEST_SRCDIR/$TEST_WORKSPACE/src/xatu/xatu"
+fixture="$TEST_SRCDIR/$TEST_WORKSPACE/src/xatu/testdata"
+tmp="${TEST_TMPDIR:-$(mktemp -d)}"
+
+cp "$fixture/clean.nix" "$tmp/clean.nix"
+cp "$fixture/invalid.nix" "$tmp/invalid.nix"
+cp "$fixture/lint_findings.nix" "$tmp/lint_findings.nix"
+
+run_xatu() {
+  local name="$1"
+  local expected_status="$2"
+  shift 2
+
+  set +e
+  "$xatu" "$@" >"$tmp/$name.stdout" 2>"$tmp/$name.stderr"
+  local actual_status="$?"
+  set -e
+
+  if [[ "$actual_status" != "$expected_status" ]]; then
+    echo "expected $name to exit $expected_status, got $actual_status" >&2
+    echo "stdout:" >&2
+    cat "$tmp/$name.stdout" >&2
+    echo "stderr:" >&2
+    cat "$tmp/$name.stderr" >&2
+    exit 1
+  fi
+}
+
+run_xatu clean 0 "$tmp/clean.nix"
+if [[ "$(<"$tmp/clean.stdout")" != "No findings." ]]; then
+  echo "expected clean output to report no findings" >&2
+  exit 1
+fi
+if [[ -s "$tmp/clean.stderr" ]]; then
+  echo "expected clean stderr to be empty" >&2
+  cat "$tmp/clean.stderr" >&2
+  exit 1
+fi
+
+run_xatu findings 1 "$tmp/lint_findings.nix"
+if ! grep -Fq "deprecated_to_path" "$tmp/findings.stdout"; then
+  echo "expected findings on stdout" >&2
+  cat "$tmp/findings.stdout" >&2
+  exit 1
+fi
+if [[ -s "$tmp/findings.stderr" ]]; then
+  echo "expected findings stderr to be empty" >&2
+  cat "$tmp/findings.stderr" >&2
+  exit 1
+fi
+
+run_xatu fatal 2 "$tmp/invalid.nix"
+if [[ -s "$tmp/fatal.stdout" ]]; then
+  echo "expected fatal stdout to be empty" >&2
+  cat "$tmp/fatal.stdout" >&2
+  exit 1
+fi
+if ! grep -Fq "FailedPrecondition: failed to parse" "$tmp/fatal.stderr"; then
+  echo "expected fatal error on stderr" >&2
+  cat "$tmp/fatal.stderr" >&2
+  exit 1
+fi

src/xatu/xatu_main.rs

@@ -1,7 +1,8 @@
 use clap::Parser;
 use status::ResultExt;
 use std::path::{Path, PathBuf};
-use xatu::SourceFile;
+use std::process::ExitCode;
+use xatu::{Report, SourceFile};
 
 fn is_nix_file(path: &Path) -> bool {
     path.extension().is_some_and(|extension| extension == "nix")
@@ -66,9 +67,7 @@ struct Args {
     paths: Vec<PathBuf>,
 }
 
-fn main() -> status::Result<()> {
-    let args = Args::parse();
-
+fn analyze(args: Args) -> status::Result<Report> {
     let paths: Vec<PathBuf> = args
         .paths
         .into_iter()
@@ -83,8 +82,22 @@ fn main() -> status::Result<()> {
         .flatten()
         .collect();
 
-    let report = xatu::future_sight(files)?;
-    print!("{report}");
-
-    Ok(())
+    xatu::future_sight(files)
+}
+
+fn main() -> ExitCode {
+    match analyze(Args::parse()) {
+        Ok(report) if report.is_clean() => {
+            println!("No findings.");
+            ExitCode::SUCCESS
+        }
+        Ok(report) => {
+            print!("{report}");
+            ExitCode::from(1)
+        }
+        Err(error) => {
+            eprintln!("{error}");
+            ExitCode::from(2)
+        }
+    }
 }