Add BATS smoke tests

.travis.yml

@@ -0,0 +1,8 @@
+language: bash
+
+before_install:
+  - git clone --depth 1 https://github.com/bats-core/bats-core.git /tmp/bats-core
+  - sudo /tmp/bats-core/install.sh /usr/local
+
+script:
+  - make test

Makefile

@@ -15,3 +15,14 @@ readme:
 	echo "## Commands" >> README.md
 	echo '' >> README.md
 	./node-reinstall -h | sed -n -e '/Commands:/,// p' | tail -n +3 >> README.md
+
+test:
+	@if command -v bats >/dev/null 2>&1; then \
+		bats test/*.bats; \
+	elif [ -x test/bats/bin/bats ]; then \
+		test/bats/bin/bats test/*.bats; \
+	else \
+		echo "BATS is required to run the test suite." >&2; \
+		echo "Install bats-core or clone it to test/bats." >&2; \
+		exit 127; \
+	fi

README.md

@@ -100,3 +100,13 @@ Whenever you feel like you need to completely re-install Node and NPM, simply ex
 	node-reinstall --nvm			re-install using stable nvm - the default
 	node-reinstall --nvm-latest		re-install using latest nvm - creationix/nvm:master
 	node-reinstall 5.0.0			specify a default node version
+
+## Testing
+
+The test suite uses [BATS](https://github.com/bats-core/bats-core) for non-destructive smoke tests. Install BATS locally, then run:
+
+```
+make test
+```
+
+The current tests only exercise safe paths such as help, version, and invalid option handling. They do not run the reinstall flow or delete local files.

test/node-reinstall.bats

@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+setup() {
+  REPO_ROOT="$(cd "$BATS_TEST_DIRNAME/.." && pwd)"
+  SCRIPT="$REPO_ROOT/node-reinstall"
+}
+
+@test "help flag prints usage without running reinstall steps" {
+  run "$SCRIPT" --help
+
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"Usage:"* ]]
+  [[ "$output" == *"--nvm-latest"* ]]
+}
+
+@test "version flag prints the script version" {
+  expected="$(grep '^VERSION=' "$SCRIPT" | sed -E 's/VERSION="([^"]+)"/\1/')"
+
+  run "$SCRIPT" --version
+
+  [ "$status" -eq 0 ]
+  [ "$output" = "$expected" ]
+}
+
+@test "unknown flags fail before destructive reinstall steps" {
+  run "$SCRIPT" --does-not-exist
+
+  [ "$status" -eq 1 ]
+  [[ "$output" == *"Unknown option"* ]]
+}