test,cli: wire pkh test into the CLI

Argument wiring only, per the report ports: the live view carries
phases and the outcome, the per-test report renders after the run
(text or --json) and decides the exit code; runtime errors exit 2.
--list-tests prints the parsed debian/tests/control and exits without
booting a testbed.

src/test/mod.rs

@@ -536,6 +536,34 @@ fn create_run_dir(package: &str, series: &str, arch: &str) -> std::io::Result<Pa
     Ok(dir)
 }
 
+/// Render the tests declared in the tree's `debian/tests/control`, one
+/// block per test (`pkh test --list-tests`).
+pub fn list_tests(tree: &Path) -> Result<String, Box<dyn std::error::Error>> {
+    let tests_control = TestsControl::parse(&tree.join("debian/tests/control"))
+        .map_err(|e| format!("cannot parse debian/tests/control: {e}"))?;
+    let mut out = String::new();
+    for test in &tests_control.tests {
+        out.push_str(&test.name);
+        out.push('\n');
+        if let Some(command) = &test.command {
+            out.push_str(&format!("  Test-Command: {command}\n"));
+        }
+        if !test.restrictions.is_empty() {
+            out.push_str(&format!(
+                "  Restrictions: {}\n",
+                test.restrictions.join(" ")
+            ));
+        }
+        if let Some(depends) = &test.depends {
+            out.push_str(&format!("  Depends: {depends}\n"));
+        }
+        if let Some(directory) = &test.tests_directory {
+            out.push_str(&format!("  Tests-Directory: {directory}\n"));
+        }
+    }
+    Ok(out)
+}
+
 /// The binary package name of a staged .deb file name.
 fn deb_binary_name(path: &Path) -> Option<String> {
     let name = path.file_name()?.to_string_lossy();