From 3163933e632b87877b414c16aeffdbc923d5a104 Mon Sep 17 00:00:00 2001
From: Adam <ashonting@gmail.com>
Date: Thu, 13 Aug 2026 18:22:48 -0500
Subject: [PATCH] fix(cli): read chi_square_indicator from the channel dict,
 not lsb_ratio

`stegg analyze <image>` crashed with KeyError: 'chi_square_indicator' on
every input.

steg_core.analyze_image() sets chi_square_indicator directly on each
channel dict (steg_core.py:875). Its own internal reader at :880 uses
ch["chi_square_indicator"], confirming flat placement is canonical. But
cli.py:469 and :502 read it nested under lsb_ratio, which only carries
zeros/ones. The zeros/ones columns were already correct and are
untouched.

Adds test_analyze_cli.py, which drives the real CLI through Typer's
CliRunner. analyze_image() itself was never broken, so a core-only test
does not catch this. The test fails with the original KeyError before
this change and passes after. Plain asserts with a __main__ runner, so
it adds no test dependency (pytest is not currently declared).
---
 cli.py              |  4 +--
 test_analyze_cli.py | 80 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100644 test_analyze_cli.py

diff --git a/cli.py b/cli.py
index c831c48..c49070b 100644
--- a/cli.py
+++ b/cli.py
@@ -466,7 +466,7 @@ def analyze(
 
     for ch_name, ch_data in analysis['channels'].items():
         lsb = ch_data['lsb_ratio']
-        indicator = lsb['chi_square_indicator']
+        indicator = ch_data['chi_square_indicator']
 
         if indicator < 0.1:
             anomaly = "[green]✓ Normal[/green]"
@@ -499,7 +499,7 @@ def analyze(
 
     # Verdict
     max_indicator = max(
-        ch['lsb_ratio']['chi_square_indicator']
+        ch['chi_square_indicator']
         for ch in analysis['channels'].values()
     )
 
diff --git a/test_analyze_cli.py b/test_analyze_cli.py
new file mode 100644
index 0000000..091bc66
--- /dev/null
+++ b/test_analyze_cli.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+"""Regression test for the `analyze` CLI command.
+
+Bug: cli.py read `chi_square_indicator` from under each channel's `lsb_ratio`
+dict, but steg_core.analyze_image() puts it directly on the channel dict
+(only `zeros`/`ones` are nested under `lsb_ratio`). Every `analyze` run
+crashed with KeyError: 'chi_square_indicator'.
+
+This exercises the real CLI path (not just analyze_image(), which was never
+broken) via Typer's CliRunner, on both a clean carrier and a stego-carrying
+image. Run directly:  python test_analyze_cli.py
+"""
+import sys
+import tempfile
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).parent))
+
+import numpy as np
+from PIL import Image
+from typer.testing import CliRunner
+
+from cli import app
+
+runner = CliRunner()
+
+
+def _noise_png(path: Path) -> None:
+    """A deterministic RGB noise image, a realistic analyze target."""
+    rng = np.random.default_rng(1234)
+    arr = rng.integers(0, 256, size=(64, 64, 3), dtype=np.uint8)
+    Image.fromarray(arr, "RGB").save(path)
+
+
+def test_analyze_runs_clean_on_noise_carrier():
+    with tempfile.TemporaryDirectory() as td:
+        img = Path(td) / "carrier.png"
+        _noise_png(img)
+        result = runner.invoke(app, ["analyze", str(img)])
+        assert result.exit_code == 0, (
+            f"analyze exited {result.exit_code}; "
+            f"exception={result.exception!r}")
+        assert result.exception is None, result.exception
+        # The channel-analysis table must actually render its anomaly verdict.
+        assert "Verdict" in result.stdout, result.stdout
+
+
+def test_analyze_runs_clean_on_stego_image():
+    """An image with LSB data hidden should still analyze without crashing
+    (and is the case the detector actually exists for)."""
+    with tempfile.TemporaryDirectory() as td:
+        carrier = Path(td) / "carrier.png"
+        hidden = Path(td) / "hidden.png"
+        _noise_png(carrier)
+        enc = runner.invoke(app, [
+            "encode-cmd", "-i", str(carrier), "-t", "regression secret",
+            "-o", str(hidden)])
+        assert enc.exit_code == 0, (
+            f"encode failed {enc.exit_code}: {enc.exception!r}")
+        result = runner.invoke(app, ["analyze", str(hidden)])
+        assert result.exit_code == 0, (
+            f"analyze exited {result.exit_code}; "
+            f"exception={result.exception!r}")
+        assert result.exception is None, result.exception
+
+
+if __name__ == "__main__":
+    failures = 0
+    for name, fn in sorted(globals().items()):
+        if name.startswith("test_") and callable(fn):
+            try:
+                fn()
+                print(f"ok  {name}")
+            except AssertionError as e:
+                failures += 1
+                print(f"FAIL {name}: {e}")
+    if failures:
+        print(f"\n{failures} test(s) failed")
+        sys.exit(1)
+    print("\nall tests passed")