test: add docker-gated integration tests for hm cache save/restore

Author: markovejnovic

crates/hm/src/commands/cache/manifest.rs

@@ -54,6 +54,7 @@ pub fn tag_from_tar_name(filename: &str) -> Option<String> {
 }
 
 #[cfg(test)]
+#[allow(clippy::unwrap_used, reason = "unit tests")]
 mod tests {
     use super::*;
 

crates/hm/tests/cache_round_trip.rs

@@ -0,0 +1,103 @@
+//! Docker-gated integration test for `hm cache save` / `hm cache restore`.
+//!
+//! Run: `cargo test -p harmont-cli --features docker-integration -- --ignored cache`
+
+#![cfg(feature = "docker-integration")]
+#![allow(
+    clippy::unwrap_used,
+    reason = "integration tests panic on unexpected failures"
+)]
+#![allow(
+    clippy::expect_used,
+    reason = "integration tests panic on unexpected failures"
+)]
+#![allow(
+    clippy::ignore_without_reason,
+    reason = "reason is in the test name and doc comment above"
+)]
+
+use assert_cmd::Command;
+use predicates::str::contains;
+use tempfile::TempDir;
+
+#[test]
+#[ignore]
+fn cache_save_creates_manifest() {
+    let cache_dir = TempDir::new().unwrap();
+    let cache_path = cache_dir.path();
+
+    let out = Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "save", cache_path.to_str().unwrap()])
+        .assert()
+        .success();
+
+    // manifest.json must exist
+    let manifest_path = cache_path.join("manifest.json");
+    assert!(manifest_path.exists(), "manifest.json should exist");
+
+    let content = std::fs::read_to_string(&manifest_path).unwrap();
+    let manifest: serde_json::Value = serde_json::from_str(&content).unwrap();
+    assert_eq!(manifest["version"], 1);
+
+    // stdout has the 16-char hex content hash
+    let stdout = String::from_utf8(out.get_output().stdout.clone()).unwrap();
+    let hash = stdout.trim();
+    assert_eq!(hash.len(), 16, "content hash should be 16 hex chars");
+    assert!(hash.chars().all(|c| c.is_ascii_hexdigit()), "should be hex");
+}
+
+#[test]
+#[ignore]
+fn cache_save_is_deterministic() {
+    let cache_dir = TempDir::new().unwrap();
+    let path = cache_dir.path().to_str().unwrap();
+
+    let out1 = Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "save", path])
+        .assert()
+        .success();
+    let out2 = Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "save", path])
+        .assert()
+        .success();
+
+    let h1 = String::from_utf8(out1.get_output().stdout.clone()).unwrap();
+    let h2 = String::from_utf8(out2.get_output().stdout.clone()).unwrap();
+    assert_eq!(h1.trim(), h2.trim(), "content hash should be deterministic");
+}
+
+#[test]
+#[ignore]
+fn cache_restore_after_save() {
+    let cache_dir = TempDir::new().unwrap();
+    let path = cache_dir.path().to_str().unwrap();
+
+    // Save first
+    Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "save", path])
+        .assert()
+        .success();
+
+    // Restore — all images already present
+    Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "restore", path])
+        .assert()
+        .success()
+        .stderr(contains("already present"));
+}
+
+#[test]
+#[ignore]
+fn cache_restore_missing_dir() {
+    Command::cargo_bin("hm")
+        .unwrap()
+        .args(["cache", "restore", "/tmp/harmont-nonexistent-cache-dir-test"])
+        .assert()
+        .success()
+        .stderr(contains("0/0"));
+}