diff --git a/tests/mutate.sh b/tests/mutate.sh
index 8891d7d..e831751 100644
--- a/tests/mutate.sh
+++ b/tests/mutate.sh
@@ -11,7 +11,7 @@ PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 MUTANT="${1:-none}"
 
 WORK=$(mktemp -d) || { echo "FATAL: mktemp failed" >&2; exit 1; }
-[ -n "$WORK" ] && [ -d "$WORK" ] || { echo "FATAL: bad WORK" >&2; exit 1; }
+if [ -z "$WORK" ] || [ ! -d "$WORK" ]; then echo "FATAL: bad WORK" >&2; exit 1; fi
 trap 'rm -rf "$WORK"' EXIT
 
 # Copy tracked files only — no .git, no run state.
diff --git a/tests/oracle-gate.sh b/tests/oracle-gate.sh
index fa883fa..ea11825 100644
--- a/tests/oracle-gate.sh
+++ b/tests/oracle-gate.sh
@@ -23,7 +23,7 @@ command -v jq >/dev/null || { echo "FATAL: jq required" >&2; exit 1; }
 command -v sha256sum >/dev/null || { echo "FATAL: sha256sum required" >&2; exit 1; }
 
 WORK=$(mktemp -d) || { echo "FATAL: mktemp failed" >&2; exit 1; }
-[ -n "$WORK" ] && [ -d "$WORK" ] || { echo "FATAL: bad WORK" >&2; exit 1; }
+if [ -z "$WORK" ] || [ ! -d "$WORK" ]; then echo "FATAL: bad WORK" >&2; exit 1; fi
 trap 'rm -rf "$WORK"' EXIT
 
 hash_file() { sha256sum "$1" | cut -d' ' -f1; }
diff --git a/tests/simple-test.sh b/tests/simple-test.sh
index f83cf87..1b18742 100644
--- a/tests/simple-test.sh
+++ b/tests/simple-test.sh
@@ -54,7 +54,7 @@ test_skip() {
 
 # Create temp directory
 TEST_TEMP=$(mktemp -d) || { echo "FATAL: mktemp failed" >&2; exit 1; }
-[ -n "$TEST_TEMP" ] && [ -d "$TEST_TEMP" ] || { echo "FATAL: bad TEST_TEMP" >&2; exit 1; }
+if [ -z "$TEST_TEMP" ] || [ ! -d "$TEST_TEMP" ]; then echo "FATAL: bad TEST_TEMP" >&2; exit 1; fi
 trap 'rm -rf "$TEST_TEMP"' EXIT
 
 echo "========================================"
diff --git a/tests/spec-map.sh b/tests/spec-map.sh
index 864ad0b..b58a6f3 100644
--- a/tests/spec-map.sh
+++ b/tests/spec-map.sh
@@ -11,7 +11,7 @@ SPEC="$SCRIPT_DIR/BEHAVIOR-SPEC.md"
 MODE="${1:-validate}"
 
 WORK=$(mktemp -d) || { echo "FATAL: mktemp failed" >&2; exit 1; }
-[ -n "$WORK" ] && [ -d "$WORK" ] || { echo "FATAL: bad WORK" >&2; exit 1; }
+if [ -z "$WORK" ] || [ ! -d "$WORK" ]; then echo "FATAL: bad WORK" >&2; exit 1; fi
 trap 'rm -rf "$WORK"' EXIT
 
 # Runtime names, from an actual run. Strip ANSI, match the three verdicts,