add tests for help and rbenv --version

test/--version.bats

@@ -0,0 +1,46 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "$HOME"
+  git config --global user.name  "Tester"
+  git config --global user.email "tester@test.local"
+}
+
+git_commit() {
+  git commit --quiet --allow-empty -m "" --allow-empty-message
+}
+
+@test "default version" {
+  assert [ ! -e "$RBENV_ROOT" ]
+  run rbenv---version
+  assert_success
+  [[ $output == "rbenv 0."* ]]
+}
+
+@test "reads version from git repo" {
+  mkdir -p "$RBENV_ROOT"
+  cd "$RBENV_ROOT"
+  git init
+  git_commit
+  git tag v0.4.1
+  git_commit
+  git_commit
+
+  cd "$RBENV_TEST_DIR"
+  run rbenv---version
+  assert_success
+  [[ $output == "rbenv 0.4.1-2-g"* ]]
+}
+
+@test "prints default version if no tags in git repo" {
+  mkdir -p "$RBENV_ROOT"
+  cd "$RBENV_ROOT"
+  git init
+  git_commit
+
+  cd "$RBENV_TEST_DIR"
+  run rbenv---version
+  [[ $output == "rbenv 0."* ]]
+}