test(output): integration coverage for ANSI color helpers

Ten tests in output_helpers_e2e.rs driving format_severity and
color directly via the lib's pub API. Existing integration tests
all use --json mode which suppresses the colour wrappers, so the
ANSI 31m/91m/33m/36m branches were entirely uncovered.

Assisted-by: Claude Code:claude-opus-4-7

Author: mikolalysenko

crates/socket-patch-cli/tests/output_helpers_e2e.rs

@@ -0,0 +1,80 @@
+//! Integration coverage for `socket_patch_cli::output` helpers.
+//! The pub `format_severity` and `color` functions are widely used
+//! by `commands/scan.rs` + `commands/list.rs` for human-mode display,
+//! but the integration test suite runs all its scan/list tests in
+//! `--json` mode (which suppresses the colour wrappers entirely), so
+//! every ANSI branch was uncovered. These tests drive each branch
+//! directly via the lib's pub API.
+
+use socket_patch_cli::output::{color, format_severity};
+
+#[test]
+fn format_severity_no_color_returns_input_verbatim() {
+    assert_eq!(format_severity("critical", false), "critical");
+    assert_eq!(format_severity("high", false), "high");
+    assert_eq!(format_severity("medium", false), "medium");
+    assert_eq!(format_severity("low", false), "low");
+    assert_eq!(format_severity("unknown", false), "unknown");
+}
+
+#[test]
+fn format_severity_critical_wraps_in_red() {
+    let out = format_severity("critical", true);
+    assert!(out.contains("\x1b[31m"), "expected red ANSI 31m; got {out:?}");
+    assert!(out.ends_with("\x1b[0m"));
+    assert!(out.contains("critical"));
+}
+
+#[test]
+fn format_severity_high_wraps_in_bright_red() {
+    let out = format_severity("high", true);
+    assert!(out.contains("\x1b[91m"), "expected bright-red 91m; got {out:?}");
+}
+
+#[test]
+fn format_severity_medium_wraps_in_yellow() {
+    let out = format_severity("medium", true);
+    assert!(out.contains("\x1b[33m"), "expected yellow 33m; got {out:?}");
+}
+
+#[test]
+fn format_severity_low_wraps_in_cyan() {
+    let out = format_severity("low", true);
+    assert!(out.contains("\x1b[36m"), "expected cyan 36m; got {out:?}");
+}
+
+#[test]
+fn format_severity_unknown_passes_through_unwrapped() {
+    // The `_` arm returns the input verbatim — no ANSI wrapper.
+    let out = format_severity("nonsense", true);
+    assert!(!out.contains("\x1b["), "unknown severity must not wrap: {out:?}");
+    assert_eq!(out, "nonsense");
+}
+
+#[test]
+fn format_severity_case_insensitive() {
+    // The lowercase match must apply to mixed-case input.
+    assert!(format_severity("CRITICAL", true).contains("\x1b[31m"));
+    assert!(format_severity("High", true).contains("\x1b[91m"));
+    assert!(format_severity("MEDIUM", true).contains("\x1b[33m"));
+    assert!(format_severity("Low", true).contains("\x1b[36m"));
+}
+
+#[test]
+fn color_with_use_color_false_returns_input() {
+    assert_eq!(color("text", "31", false), "text");
+}
+
+#[test]
+fn color_with_use_color_true_wraps_with_code() {
+    let out = color("text", "31", true);
+    assert_eq!(out, "\x1b[31mtext\x1b[0m");
+}
+
+#[test]
+fn color_with_empty_text_still_wraps() {
+    // Edge case: empty input still gets the ANSI envelope when
+    // colour is enabled.
+    let out = color("", "31", true);
+    assert_eq!(out, "\x1b[31m\x1b[0m");
+}