CLI: regression tests for render --progress (#1778) and template media values (#1787)

- render --progress with a piped stderr writes well-formed
  `progress <done> <total> <elapsed> <left|->` lines, one per change, and
  the same render without the flag writes none.
- A template's Media Replacement control takes {"path"|"file"|"media": …},
  is found by name ignoring case, and a path that cannot be imported fails
  with an error naming the control and the path.

apps/effectcraft-cli/tests/cli.rs

@@ -623,3 +623,47 @@ fn gpu_adapter_name_empty_is_unset() {
     let all = format!("{}{}", String::from_utf8_lossy(&out.stdout), String::from_utf8_lossy(&out.stderr));
     assert!(!all.contains("WGPU_ADAPTER_NAME"), "{all}");
 }
+
+/// Renders two seconds of the demo at quarter resolution (long enough for several progress
+/// updates) and returns stderr, which `output()` reads through a pipe: not a terminal.
+fn render_demo_stderr(name: &str, extra: &[&str]) -> String {
+    let out = tmp(name);
+    let mut args = vec!["render", "--demo", "--format", "gif", "--start", "0", "--end", "2", "--resolution", "quarter", "--out", out.to_str().unwrap()];
+    args.extend_from_slice(extra);
+    let o = bin().args(&args).output().unwrap();
+    let stderr = String::from_utf8_lossy(&o.stderr).to_string();
+    assert!(o.status.success(), "{args:?}: {stderr}");
+    let _ = std::fs::remove_file(out);
+    stderr
+}
+
+/// `render --progress` with a piped stderr reports the render's frames as
+/// `progress <frames done> <frames total> <seconds elapsed> <seconds left|->` lines, one per
+/// change (#1778).
+#[test]
+fn render_progress_reports_frames_on_a_piped_stderr() {
+    let stderr = render_demo_stderr("progress.gif", &["--progress"]);
+    let mut last_done = None;
+    let mut totals = vec![];
+    for line in stderr.lines().filter(|l| l.starts_with("progress")) {
+        let fields: Vec<&str> = line.split(' ').collect();
+        assert_eq!(fields.len(), 5, "{line}");
+        let done: u64 = fields[1].parse().unwrap_or_else(|e| panic!("{line}: frames done: {e}"));
+        let total: u64 = fields[2].parse().unwrap_or_else(|e| panic!("{line}: frames total: {e}"));
+        let elapsed: f64 = fields[3].parse().unwrap_or_else(|e| panic!("{line}: seconds elapsed: {e}"));
+        assert!(fields[4] == "-" || fields[4].parse::<f64>().is_ok_and(|left| left >= 0.0), "{line}: seconds left");
+        assert!(done <= total && total > 0 && elapsed >= 0.0, "{line}");
+        assert!(last_done.is_none_or(|last| done > last), "one line per change, and frames only go up: {stderr}");
+        last_done = Some(done);
+        totals.push(total);
+    }
+    assert!(!totals.is_empty(), "no progress line on a piped stderr: {stderr}");
+    assert!(totals.iter().all(|&t| t == totals[0]), "one render, one total: {stderr}");
+}
+
+/// Without `--progress`, the same render writes no progress lines to a piped stderr (#1778).
+#[test]
+fn render_without_progress_writes_no_progress_lines() {
+    let stderr = render_demo_stderr("no-progress.gif", &[]);
+    assert!(!stderr.lines().any(|l| l.starts_with("progress")), "{stderr}");
+}