Improve `git --version` git revision lookup

It doesn't try to chdir into RBENV_ROOT anymore because that might be
a location of an unrelated rbenv install that might have a different
version than the current one that is installed e.g. via a package
manager such as Homebrew.

Now just tries the repo where the source files (`libexec/*`) are
located, and if that isn't a valid rbenv repo, bail out early.

libexec/rbenv---version

@@ -15,12 +15,9 @@ set -e
 version="0.4.0"
 git_revision=""
 
-for source_dir in "${BASH_SOURCE%/*}" "$RBENV_ROOT"; do
-  if cd "$source_dir" 2>/dev/null && git remote -v 2>/dev/null | grep -q rbenv; then
-    git_revision="$(git describe --tags HEAD 2>/dev/null || true)"
-    git_revision="${git_revision#v}"
-    [ -z "$git_revision" ] || break
-  fi
-done
+if cd "${BASH_SOURCE%/*}" 2>/dev/null && git remote -v 2>/dev/null | grep -q rbenv; then
+  git_revision="$(git describe --tags HEAD 2>/dev/null || true)"
+  git_revision="${git_revision#v}"
+fi
 
 echo "rbenv ${git_revision:-$version}"

test/--version.bats

@@ -2,22 +2,13 @@
 
 load test_helper
 
+export GIT_DIR="${RBENV_TEST_DIR}/.git"
+
 setup() {
   mkdir -p "$HOME"
   git config --global user.name  "Tester"
   git config --global user.email "tester@test.local"
-
-  mkdir -p "${RBENV_TEST_DIR}/bin"
-  cat > "${RBENV_TEST_DIR}/bin/git" <<CMD
-#!$BASH
-if [[ \$1 == remote && \$PWD != "\$RBENV_TEST_DIR"/* ]]; then
-  echo "not allowed" >&2
-  exit 1
-else
-  exec $(which git) "\$@"
-fi
-CMD
-  chmod +x "${RBENV_TEST_DIR}/bin/git"
+  cd "$RBENV_TEST_DIR"
 }
 
 git_commit() {
@@ -28,26 +19,21 @@ git_commit() {
   assert [ ! -e "$RBENV_ROOT" ]
   run rbenv---version
   assert_success
-  [[ $output == "rbenv 0."* ]]
+  [[ $output == "rbenv "?.?.? ]]
 }
 
 @test "doesn't read version from non-rbenv repo" {
-  mkdir -p "$RBENV_ROOT"
-  cd "$RBENV_ROOT"
   git init
   git remote add origin https://github.com/homebrew/homebrew.git
   git_commit
   git tag v1.0
 
-  cd "$RBENV_TEST_DIR"
   run rbenv---version
   assert_success
-  [[ $output == "rbenv 0."* ]]
+  [[ $output == "rbenv "?.?.? ]]
 }
 
 @test "reads version from git repo" {
-  mkdir -p "$RBENV_ROOT"
-  cd "$RBENV_ROOT"
   git init
   git remote add origin https://github.com/rbenv/rbenv.git
   git_commit
@@ -55,20 +41,15 @@ git_commit() {
   git_commit
   git_commit
 
-  cd "$RBENV_TEST_DIR"
   run rbenv---version
-  assert_success
-  [[ $output == "rbenv 0.4.1-2-g"* ]]
+  assert_success "rbenv 0.4.1-2-g$(git rev-parse --short HEAD)"
 }
 
 @test "prints default version if no tags in git repo" {
-  mkdir -p "$RBENV_ROOT"
-  cd "$RBENV_ROOT"
   git init
   git remote add origin https://github.com/rbenv/rbenv.git
   git_commit
 
-  cd "$RBENV_TEST_DIR"
   run rbenv---version
-  [[ $output == "rbenv 0."* ]]
+  [[ $output == "rbenv "?.?.? ]]
 }