test: cover compiler cli tooling

fec/tests/run-cli-tests.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+set -eu
+root=$(CDPATH= cd -- "$(dirname "$0")/.." && pwd)
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT HUP INT TERM
+
+"$root"/fec --dump-tokens "$root"/tests/pass/basic.fe >"$tmp/tokens.out"
+grep 'unit' "$tmp/tokens.out" >/dev/null
+grep 'identifier' "$tmp/tokens.out" >/dev/null
+grep 'eof' "$tmp/tokens.out" >/dev/null
+
+"$root"/fec --check "$root"/tests/m2/hello.fe >"$tmp/check.out"
+if [ -s "$tmp/check.out" ]; then
+    echo "FAIL: --check produced stdout"
+    exit 1
+fi
+
+if "$root"/fec --check "$root"/tests/m2/bad-condition.fe >"$tmp/bad.out" 2>"$tmp/diag.out"; then
+    echo "FAIL: --check accepted invalid input"
+    exit 1
+fi
+grep 'error:' "$tmp/diag.out" >/dev/null
+grep '^  [0-9][0-9]* | ' "$tmp/diag.out" >/dev/null
+grep ' | .*\^' "$tmp/diag.out" >/dev/null
+
+echo "CLI tests: token dump, check mode, and source diagnostics passed"