Squash Odysseus development history

tests/test_cookbook_error_tail_lines.py

@@ -0,0 +1,56 @@
+"""Behavioral guard for the cookbook error output-tail expansion.
+
+When a task reaches status "error" the status endpoint previously returned
+only the last 12 lines of the subprocess log. The "Copy last 50 lines"
+context-menu action was therefore copying the same 12 lines — useless for
+diagnosing failures that emit long stack traces or build output.
+
+`error_aware_output_tail` now returns the last 50 lines on error and keeps
+the cheaper 12-line tail for running/other tasks.
+"""
+from routes.cookbook_output import error_aware_output_tail
+
+
+def _snapshot(n):
+    return "\n".join(f"line {i}" for i in range(n))
+
+
+def test_error_status_returns_last_50_lines():
+    snap = _snapshot(200)
+    tail = error_aware_output_tail(snap, "error")
+    lines = tail.splitlines()
+    assert len(lines) == 50, f"error tail should be 50 lines, got {len(lines)}"
+    assert lines[0] == "line 150"
+    assert lines[-1] == "line 199"
+
+
+def test_non_error_status_returns_last_12_lines():
+    snap = _snapshot(200)
+    for status in ("running", "ready", "completed", "stopped", "unknown"):
+        tail = error_aware_output_tail(snap, status)
+        lines = tail.splitlines()
+        assert len(lines) == 12, f"{status} tail should be 12 lines, got {len(lines)}"
+        assert lines[-1] == "line 199"
+
+
+def test_short_snapshot_returns_all_lines():
+    # Fewer lines than the cap — return everything, no padding.
+    snap = _snapshot(5)
+    assert error_aware_output_tail(snap, "error").splitlines() == [
+        "line 0", "line 1", "line 2", "line 3", "line 4",
+    ]
+    assert len(error_aware_output_tail(snap, "running").splitlines()) == 5
+
+
+def test_empty_snapshot_returns_empty_string():
+    assert error_aware_output_tail("", "error") == ""
+    assert error_aware_output_tail("", "running") == ""
+
+
+def test_error_tail_is_wider_than_non_error():
+    snap = _snapshot(100)
+    err = error_aware_output_tail(snap, "error").splitlines()
+    run = error_aware_output_tail(snap, "running").splitlines()
+    assert len(err) > len(run)
+    # The non-error tail is a strict suffix of the error tail.
+    assert err[-len(run):] == run