diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 00000000..ef43ae71
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,4 @@
+install: git clone https://github.com/sstephenson/bats.git
+script: bats/bin/bats --tap test
+# skips unnecessary Python-specific setup
+language: c
diff --git a/test/--version.bats b/test/--version.bats
new file mode 100644
index 00000000..e035211a
--- /dev/null
+++ b/test/--version.bats
@@ -0,0 +1,46 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "$HOME"
+  git config --global user.name  "Tester"
+  git config --global user.email "tester@test.local"
+}
+
+git_commit() {
+  git commit --quiet --allow-empty -m "empty"
+}
+
+@test "default version" {
+  assert [ ! -e "$PYENV_ROOT" ]
+  run pyenv---version
+  assert_success
+  [[ $output == "pyenv 0."* ]]
+}
+
+@test "reads version from git repo" {
+  mkdir -p "$PYENV_ROOT"
+  cd "$PYENV_ROOT"
+  git init
+  git_commit
+  git tag v0.4.1
+  git_commit
+  git_commit
+
+  cd "$PYENV_TEST_DIR"
+  run pyenv---version
+  assert_success
+  [[ $output == "pyenv 0.4.1-2-g"* ]]
+}
+
+@test "prints default version if no tags in git repo" {
+  mkdir -p "$PYENV_ROOT"
+  cd "$PYENV_ROOT"
+  git init
+  git_commit
+
+  cd "$PYENV_TEST_DIR"
+  run pyenv---version
+  [[ $output == "pyenv 0."* ]]
+}
diff --git a/test/commands.bats b/test/commands.bats
new file mode 100644
index 00000000..b0664a6f
--- /dev/null
+++ b/test/commands.bats
@@ -0,0 +1,39 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "commands" {
+  run pyenv-commands
+  assert_success
+  assert_line "init"
+  assert_line "rehash"
+  assert_line "shell"
+  refute_line "sh-shell"
+  assert_line "echo"
+}
+
+@test "commands --sh" {
+  run pyenv-commands --sh
+  assert_success
+  refute_line "init"
+  assert_line "shell"
+}
+
+@test "commands in path with spaces" {
+  path="${PYENV_TEST_DIR}/my commands"
+  cmd="${path}/pyenv-sh-hello"
+  mkdir -p "$path"
+  touch "$cmd"
+  chmod +x "$cmd"
+
+  PATH="${path}:$PATH" run pyenv-commands --sh
+  assert_success
+  assert_line "hello"
+}
+
+@test "commands --no-sh" {
+  run pyenv-commands --no-sh
+  assert_success
+  assert_line "init"
+  refute_line "shell"
+}
diff --git a/test/completions.bats b/test/completions.bats
new file mode 100644
index 00000000..8012a98d
--- /dev/null
+++ b/test/completions.bats
@@ -0,0 +1,46 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_command() {
+  bin="${PYENV_TEST_DIR}/bin"
+  mkdir -p "$bin"
+  echo "$2" > "${bin}/$1"
+  chmod +x "${bin}/$1"
+}
+
+@test "command with no completion support" {
+  create_command "pyenv-hello" "#!$BASH
+    echo hello"
+  run pyenv-completions hello
+  assert_success ""
+}
+
+@test "command with completion support" {
+  create_command "pyenv-hello" "#!$BASH
+# provide pyenv completions
+if [[ \$1 = --complete ]]; then
+  echo hello
+else
+  exit 1
+fi"
+  run pyenv-completions hello
+  assert_success "hello"
+}
+
+@test "forwards extra arguments" {
+  create_command "pyenv-hello" "#!$BASH
+# provide pyenv completions
+if [[ \$1 = --complete ]]; then
+  shift 1
+  for arg; do echo \$arg; done
+else
+  exit 1
+fi"
+  run pyenv-completions hello happy world
+  assert_success
+  assert_output <<OUT
+happy
+world
+OUT
+}
diff --git a/test/exec.bats b/test/exec.bats
new file mode 100644
index 00000000..c81db709
--- /dev/null
+++ b/test/exec.bats
@@ -0,0 +1,113 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_executable() {
+  name="${1?}"
+  shift 1
+  bin="${PYENV_ROOT}/versions/${PYENV_VERSION}/bin"
+  mkdir -p "$bin"
+  { if [ $# -eq 0 ]; then cat -
+    else echo "$@"
+    fi
+  } | sed -Ee '1s/^ +//' > "${bin}/$name"
+  chmod +x "${bin}/$name"
+}
+
+@test "fails with invalid version" {
+  export PYENV_VERSION="2.0"
+  run pyenv-exec python -v
+  assert_failure "pyenv: version \`2.0' is not installed"
+}
+
+@test "completes with names of executables" {
+  export PYENV_VERSION="2.0"
+  create_executable "python" "#!/bin/sh"
+  create_executable "rake" "#!/bin/sh"
+
+  pyenv-rehash
+  run pyenv-completions exec
+  assert_success
+  assert_output <<OUT
+rake
+python
+OUT
+}
+
+@test "supports hook path with spaces" {
+  hook_path="${PYENV_TEST_DIR}/custom stuff/pyenv hooks"
+  mkdir -p "${hook_path}/exec"
+  echo "export HELLO='from hook'" > "${hook_path}/exec/hello.bash"
+
+  export PYENV_VERSION=system
+  PYENV_HOOK_PATH="$hook_path" run pyenv-exec env
+  assert_success
+  assert_line "HELLO=from hook"
+}
+
+@test "carries original IFS within hooks" {
+  hook_path="${PYENV_TEST_DIR}/pyenv.d"
+  mkdir -p "${hook_path}/exec"
+  cat > "${hook_path}/exec/hello.bash" <<SH
+hellos=(\$(printf "hello\\tugly world\\nagain"))
+echo HELLO="\$(printf ":%s" "\${hellos[@]}")"
+SH
+
+  export PYENV_VERSION=system
+  PYENV_HOOK_PATH="$hook_path" IFS=$' \t\n' run pyenv-exec env
+  assert_success
+  assert_line "HELLO=:hello:ugly:world:again"
+}
+
+@test "forwards all arguments" {
+  export PYENV_VERSION="2.0"
+  create_executable "python" <<SH
+#!$BASH
+echo \$0
+for arg; do
+  # hack to avoid bash builtin echo which can't output '-e'
+  printf "  %s\\n" "\$arg"
+done
+SH
+
+  run pyenv-exec python -w "/path to/python script.rb" -- extra args
+  assert_success
+  assert_output <<OUT
+${PYENV_ROOT}/versions/2.0/bin/python
+  -w
+  /path to/python script.rb
+  --
+  extra
+  args
+OUT
+}
+
+@test "supports python -S <cmd>" {
+  export PYENV_VERSION="2.0"
+
+  # emulate `python -S' behavior
+  create_executable "python" <<SH
+#!$BASH
+if [[ \$1 == "-S"* ]]; then
+  found="\$(PATH="\${PYTHONPATH:-\$PATH}" which \$2)"
+  # assert that the found executable has python for shebang
+  if head -1 "\$found" | grep python >/dev/null; then
+    \$BASH "\$found"
+  else
+    echo "python: no Python script found in input (LoadError)" >&2
+    exit 1
+  fi
+else
+  echo 'python 2.0 (pyenv test)'
+fi
+SH
+
+  create_executable "rake" <<SH
+#!/usr/bin/env python
+echo hello rake
+SH
+
+  pyenv-rehash
+  run python -S rake
+  assert_success "hello rake"
+}
diff --git a/test/global.bats b/test/global.bats
new file mode 100644
index 00000000..743c7e80
--- /dev/null
+++ b/test/global.bats
@@ -0,0 +1,31 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "default" {
+  run pyenv global
+  assert_success
+  assert_output "system"
+}
+
+@test "read PYENV_ROOT/version" {
+  mkdir -p "$PYENV_ROOT"
+  echo "1.2.3" > "$PYENV_ROOT/version"
+  run pyenv-global
+  assert_success
+  assert_output "1.2.3"
+}
+
+@test "set PYENV_ROOT/version" {
+  mkdir -p "$PYENV_ROOT/versions/1.2.3"
+  run pyenv-global "1.2.3"
+  assert_success
+  run pyenv global
+  assert_success "1.2.3"
+}
+
+@test "fail setting invalid PYENV_ROOT/version" {
+  mkdir -p "$PYENV_ROOT"
+  run pyenv-global "1.2.3"
+  assert_failure "pyenv: version \`1.2.3' not installed"
+}
diff --git a/test/help.bats b/test/help.bats
new file mode 100644
index 00000000..db178c2b
--- /dev/null
+++ b/test/help.bats
@@ -0,0 +1,115 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "without args shows summary of common commands" {
+  run pyenv-help
+  assert_success
+  assert_line "Usage: pyenv <command> [<args>]"
+  assert_line "Some useful pyenv commands are:"
+}
+
+@test "invalid command" {
+  run pyenv-help hello
+  assert_failure "pyenv: no such command \`hello'"
+}
+
+@test "shows help for a specific command" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  cat > "${PYENV_TEST_DIR}/bin/pyenv-hello" <<SH
+#!shebang
+# Usage: pyenv hello <world>
+# Summary: Says "hello" to you, from pyenv
+# This command is useful for saying hello.
+echo hello
+SH
+
+  run pyenv-help hello
+  assert_success
+  assert_output <<SH
+Usage: pyenv hello <world>
+
+This command is useful for saying hello.
+SH
+}
+
+@test "replaces missing extended help with summary text" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  cat > "${PYENV_TEST_DIR}/bin/pyenv-hello" <<SH
+#!shebang
+# Usage: pyenv hello <world>
+# Summary: Says "hello" to you, from pyenv
+echo hello
+SH
+
+  run pyenv-help hello
+  assert_success
+  assert_output <<SH
+Usage: pyenv hello <world>
+
+Says "hello" to you, from pyenv
+SH
+}
+
+@test "extracts only usage" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  cat > "${PYENV_TEST_DIR}/bin/pyenv-hello" <<SH
+#!shebang
+# Usage: pyenv hello <world>
+# Summary: Says "hello" to you, from pyenv
+# This extended help won't be shown.
+echo hello
+SH
+
+  run pyenv-help --usage hello
+  assert_success "Usage: pyenv hello <world>"
+}
+
+@test "multiline usage section" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  cat > "${PYENV_TEST_DIR}/bin/pyenv-hello" <<SH
+#!shebang
+# Usage: pyenv hello <world>
+#        pyenv hi [everybody]
+#        pyenv hola --translate
+# Summary: Says "hello" to you, from pyenv
+# Help text.
+echo hello
+SH
+
+  run pyenv-help hello
+  assert_success
+  assert_output <<SH
+Usage: pyenv hello <world>
+       pyenv hi [everybody]
+       pyenv hola --translate
+
+Help text.
+SH
+}
+
+@test "multiline extended help section" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  cat > "${PYENV_TEST_DIR}/bin/pyenv-hello" <<SH
+#!shebang
+# Usage: pyenv hello <world>
+# Summary: Says "hello" to you, from pyenv
+# This is extended help text.
+# It can contain multiple lines.
+#
+# And paragraphs.
+
+echo hello
+SH
+
+  run pyenv-help hello
+  assert_success
+  assert_output <<SH
+Usage: pyenv hello <world>
+
+This is extended help text.
+It can contain multiple lines.
+
+And paragraphs.
+SH
+}
diff --git a/test/hooks.bats b/test/hooks.bats
new file mode 100644
index 00000000..46583aee
--- /dev/null
+++ b/test/hooks.bats
@@ -0,0 +1,65 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_hook() {
+  mkdir -p "$1/$2"
+  touch "$1/$2/$3"
+}
+
+@test "prints usage help given no argument" {
+  run pyenv-hooks
+  assert_failure "Usage: pyenv hooks <command>"
+}
+
+@test "prints list of hooks" {
+  path1="${PYENV_TEST_DIR}/pyenv.d"
+  path2="${PYENV_TEST_DIR}/etc/pyenv_hooks"
+  create_hook "$path1" exec "hello.bash"
+  create_hook "$path1" exec "ahoy.bash"
+  create_hook "$path1" exec "invalid.sh"
+  create_hook "$path1" which "boom.bash"
+  create_hook "$path2" exec "bueno.bash"
+
+  PYENV_HOOK_PATH="$path1:$path2" run pyenv-hooks exec
+  assert_success
+  assert_output <<OUT
+${PYENV_TEST_DIR}/pyenv.d/exec/ahoy.bash
+${PYENV_TEST_DIR}/pyenv.d/exec/hello.bash
+${PYENV_TEST_DIR}/etc/pyenv_hooks/exec/bueno.bash
+OUT
+}
+
+@test "supports hook paths with spaces" {
+  path1="${PYENV_TEST_DIR}/my hooks/pyenv.d"
+  path2="${PYENV_TEST_DIR}/etc/pyenv hooks"
+  create_hook "$path1" exec "hello.bash"
+  create_hook "$path2" exec "ahoy.bash"
+
+  PYENV_HOOK_PATH="$path1:$path2" run pyenv-hooks exec
+  assert_success
+  assert_output <<OUT
+${PYENV_TEST_DIR}/my hooks/pyenv.d/exec/hello.bash
+${PYENV_TEST_DIR}/etc/pyenv hooks/exec/ahoy.bash
+OUT
+}
+
+@test "resolves relative paths" {
+  path="${PYENV_TEST_DIR}/pyenv.d"
+  create_hook "$path" exec "hello.bash"
+  mkdir -p "$HOME"
+
+  PYENV_HOOK_PATH="${HOME}/../pyenv.d" run pyenv-hooks exec
+  assert_success "${PYENV_TEST_DIR}/pyenv.d/exec/hello.bash"
+}
+
+@test "resolves symlinks" {
+  path="${PYENV_TEST_DIR}/pyenv.d"
+  mkdir -p "${path}/exec"
+  mkdir -p "$HOME"
+  touch "${HOME}/hola.bash"
+  ln -s "../../home/hola.bash" "${path}/exec/hello.bash"
+
+  PYENV_HOOK_PATH="$path" run pyenv-hooks exec
+  assert_success "${HOME}/hola.bash"
+}
diff --git a/test/init.bats b/test/init.bats
new file mode 100644
index 00000000..71cbd853
--- /dev/null
+++ b/test/init.bats
@@ -0,0 +1,79 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "creates shims and versions directories" {
+  assert [ ! -d "${PYENV_ROOT}/shims" ]
+  assert [ ! -d "${PYENV_ROOT}/versions" ]
+  run pyenv-init -
+  assert_success
+  assert [ -d "${PYENV_ROOT}/shims" ]
+  assert [ -d "${PYENV_ROOT}/versions" ]
+}
+
+@test "auto rehash" {
+  run pyenv-init -
+  assert_success
+  assert_line "pyenv rehash 2>/dev/null"
+}
+
+@test "setup shell completions" {
+  root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
+  run pyenv-init - bash
+  assert_success
+  assert_line "source '${root}/libexec/../completions/pyenv.bash'"
+}
+
+@test "detect parent shell" {
+  root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
+  SHELL=/bin/false run pyenv-init -
+  assert_success
+  assert_line "export PYENV_SHELL=bash"
+}
+
+@test "setup shell completions (fish)" {
+  root="$(cd $BATS_TEST_DIRNAME/.. && pwd)"
+  run pyenv-init - fish
+  assert_success
+  assert_line ". '${root}/libexec/../completions/pyenv.fish'"
+}
+
+@test "fish instructions" {
+  run pyenv-init fish
+  assert [ "$status" -eq 1 ]
+  assert_line 'status --is-interactive; and . (pyenv init -|psub)'
+}
+
+@test "option to skip rehash" {
+  run pyenv-init - --no-rehash
+  assert_success
+  refute_line "pyenv rehash 2>/dev/null"
+}
+
+@test "adds shims to PATH" {
+  export PATH="${BATS_TEST_DIRNAME}/../libexec:/usr/bin:/bin"
+  run pyenv-init - bash
+  assert_success
+  assert_line 0 'export PATH="'${PYENV_ROOT}'/shims:${PATH}"'
+}
+
+@test "adds shims to PATH (fish)" {
+  export PATH="${BATS_TEST_DIRNAME}/../libexec:/usr/bin:/bin"
+  run pyenv-init - fish
+  assert_success
+  assert_line 0 "setenv PATH '${PYENV_ROOT}/shims' \$PATH"
+}
+
+@test "doesn't add shims to PATH more than once" {
+  export PATH="${PYENV_ROOT}/shims:$PATH"
+  run pyenv-init - bash
+  assert_success
+  refute_line 'export PATH="'${PYENV_ROOT}'/shims:${PATH}"'
+}
+
+@test "doesn't add shims to PATH more than once (fish)" {
+  export PATH="${PYENV_ROOT}/shims:$PATH"
+  run pyenv-init - fish
+  assert_success
+  refute_line 'setenv PATH "'${PYENV_ROOT}'/shims" $PATH ;'
+}
diff --git a/test/libexec/rbenv-echo b/test/libexec/rbenv-echo
new file mode 100755
index 00000000..0a802df4
--- /dev/null
+++ b/test/libexec/rbenv-echo
@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+eval "echo \$$1"
diff --git a/test/local.bats b/test/local.bats
new file mode 100644
index 00000000..d9901822
--- /dev/null
+++ b/test/local.bats
@@ -0,0 +1,103 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "${PYENV_TEST_DIR}/myproject"
+  cd "${PYENV_TEST_DIR}/myproject"
+}
+
+@test "no version" {
+  assert [ ! -e "${PWD}/.python-version" ]
+  run pyenv-local
+  assert_failure "pyenv: no local version configured for this directory"
+}
+
+@test "local version" {
+  echo "1.2.3" > .python-version
+  run pyenv-local
+  assert_success "1.2.3"
+}
+
+@test "supports legacy .pyenv-version file" {
+  echo "1.2.3" > .pyenv-version
+  run pyenv-local
+  assert_success "1.2.3"
+}
+
+@test "local .python-version has precedence over .pyenv-version" {
+  echo "1.8" > .pyenv-version
+  echo "2.0" > .python-version
+  run pyenv-local
+  assert_success "2.0"
+}
+
+@test "ignores version in parent directory" {
+  echo "1.2.3" > .python-version
+  mkdir -p "subdir" && cd "subdir"
+  run pyenv-local
+  assert_failure
+}
+
+@test "ignores PYENV_DIR" {
+  echo "1.2.3" > .python-version
+  mkdir -p "$HOME"
+  echo "2.0-home" > "${HOME}/.python-version"
+  PYENV_DIR="$HOME" run pyenv-local
+  assert_success "1.2.3"
+}
+
+@test "sets local version" {
+  mkdir -p "${PYENV_ROOT}/versions/1.2.3"
+  run pyenv-local 1.2.3
+  assert_success ""
+  assert [ "$(cat .python-version)" = "1.2.3" ]
+}
+
+@test "changes local version" {
+  echo "1.0-pre" > .python-version
+  mkdir -p "${PYENV_ROOT}/versions/1.2.3"
+  run pyenv-local
+  assert_success "1.0-pre"
+  run pyenv-local 1.2.3
+  assert_success ""
+  assert [ "$(cat .python-version)" = "1.2.3" ]
+}
+
+@test "renames .pyenv-version to .python-version" {
+  echo "1.8.7" > .pyenv-version
+  mkdir -p "${PYENV_ROOT}/versions/1.9.3"
+  run pyenv-local
+  assert_success "1.8.7"
+  run pyenv-local "1.9.3"
+  assert_success
+  assert_output <<OUT
+pyenv: removed existing \`.pyenv-version' file and migrated
+       local version specification to \`.python-version' file
+OUT
+  assert [ ! -e .pyenv-version ]
+  assert [ "$(cat .python-version)" = "1.9.3" ]
+}
+
+@test "doesn't rename .pyenv-version if changing the version failed" {
+  echo "1.8.7" > .pyenv-version
+  assert [ ! -e "${PYENV_ROOT}/versions/1.9.3" ]
+  run pyenv-local "1.9.3"
+  assert_failure "pyenv: version \`1.9.3' not installed"
+  assert [ ! -e .python-version ]
+  assert [ "$(cat .pyenv-version)" = "1.8.7" ]
+}
+
+@test "unsets local version" {
+  touch .python-version
+  run pyenv-local --unset
+  assert_success ""
+  assert [ ! -e .pyenv-version ]
+}
+
+@test "unsets alternate version file" {
+  touch .pyenv-version
+  run pyenv-local --unset
+  assert_success ""
+  assert [ ! -e .pyenv-version ]
+}
diff --git a/test/prefix.bats b/test/prefix.bats
new file mode 100644
index 00000000..1245ceeb
--- /dev/null
+++ b/test/prefix.bats
@@ -0,0 +1,39 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "prefix" {
+  mkdir -p "${PYENV_TEST_DIR}/myproject"
+  cd "${PYENV_TEST_DIR}/myproject"
+  echo "1.2.3" > .python-version
+  mkdir -p "${PYENV_ROOT}/versions/1.2.3"
+  run pyenv-prefix
+  assert_success "${PYENV_ROOT}/versions/1.2.3"
+}
+
+@test "prefix for invalid version" {
+  PYENV_VERSION="1.2.3" run pyenv-prefix
+  assert_failure "pyenv: version \`1.2.3' not installed"
+}
+
+@test "prefix for system" {
+  mkdir -p "${PYENV_TEST_DIR}/bin"
+  touch "${PYENV_TEST_DIR}/bin/python"
+  chmod +x "${PYENV_TEST_DIR}/bin/python"
+  PYENV_VERSION="system" run pyenv-prefix
+  assert_success "$PYENV_TEST_DIR"
+}
+
+@test "prefix for invalid system" {
+  USRBIN_ALT="${PYENV_TEST_DIR}/usr-bin-alt"
+  mkdir -p "$USRBIN_ALT"
+  for util in head readlink greadlink; do
+    if [ -x "/usr/bin/$util" ]; then
+      ln -s "/usr/bin/$util" "${USRBIN_ALT}/$util"
+    fi
+  done
+  PATH_WITHOUT_PYTHON="${PATH/\/usr\/bin:/$USRBIN_ALT:}"
+
+  PATH="$PATH_WITHOUT_PYTHON" run pyenv-prefix system
+  assert_failure "pyenv: system version not found in PATH"
+}
diff --git a/test/rbenv.bats b/test/rbenv.bats
new file mode 100644
index 00000000..e16b636d
--- /dev/null
+++ b/test/rbenv.bats
@@ -0,0 +1,47 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "blank invocation" {
+  run pyenv
+  assert_success
+  assert [ "${lines[0]}" = "pyenv 0.4.0" ]
+}
+
+@test "invalid command" {
+  run pyenv does-not-exist
+  assert_failure
+  assert_output "pyenv: no such command \`does-not-exist'"
+}
+
+@test "default PYENV_ROOT" {
+  PYENV_ROOT="" HOME=/home/mislav run pyenv root
+  assert_success
+  assert_output "/home/mislav/.pyenv"
+}
+
+@test "inherited PYENV_ROOT" {
+  PYENV_ROOT=/opt/pyenv run pyenv root
+  assert_success
+  assert_output "/opt/pyenv"
+}
+
+@test "default PYENV_DIR" {
+  run pyenv echo PYENV_DIR
+  assert_output "$(pwd)"
+}
+
+@test "inherited PYENV_DIR" {
+  dir="${BATS_TMPDIR}/myproject"
+  mkdir -p "$dir"
+  PYENV_DIR="$dir" run pyenv echo PYENV_DIR
+  assert_output "$dir"
+}
+
+@test "invalid PYENV_DIR" {
+  dir="${BATS_TMPDIR}/does-not-exist"
+  assert [ ! -d "$dir" ]
+  PYENV_DIR="$dir" run pyenv echo PYENV_DIR
+  assert_failure
+  assert_output "pyenv: cannot change working directory to \`$dir'"
+}
diff --git a/test/rehash.bats b/test/rehash.bats
new file mode 100755
index 00000000..fbe70f83
--- /dev/null
+++ b/test/rehash.bats
@@ -0,0 +1,114 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_executable() {
+  local bin="${PYENV_ROOT}/versions/${1}/bin"
+  mkdir -p "$bin"
+  touch "${bin}/$2"
+  chmod +x "${bin}/$2"
+}
+
+@test "empty rehash" {
+  assert [ ! -d "${PYENV_ROOT}/shims" ]
+  run pyenv-rehash
+  assert_success ""
+  assert [ -d "${PYENV_ROOT}/shims" ]
+  rmdir "${PYENV_ROOT}/shims"
+}
+
+@test "non-writable shims directory" {
+  mkdir -p "${PYENV_ROOT}/shims"
+  chmod -w "${PYENV_ROOT}/shims"
+  run pyenv-rehash
+  assert_failure "pyenv: cannot rehash: ${PYENV_ROOT}/shims isn't writable"
+}
+
+@test "rehash in progress" {
+  mkdir -p "${PYENV_ROOT}/shims"
+  touch "${PYENV_ROOT}/shims/.pyenv-shim"
+  run pyenv-rehash
+  assert_failure "pyenv: cannot rehash: ${PYENV_ROOT}/shims/.pyenv-shim exists"
+}
+
+@test "creates shims" {
+  create_executable "1.8" "python"
+  create_executable "1.8" "rake"
+  create_executable "2.0" "python"
+  create_executable "2.0" "rspec"
+
+  assert [ ! -e "${PYENV_ROOT}/shims/python" ]
+  assert [ ! -e "${PYENV_ROOT}/shims/rake" ]
+  assert [ ! -e "${PYENV_ROOT}/shims/rspec" ]
+
+  run pyenv-rehash
+  assert_success ""
+
+  run ls "${PYENV_ROOT}/shims"
+  assert_success
+  assert_output <<OUT
+rake
+rspec
+python
+OUT
+}
+
+@test "removes stale shims" {
+  mkdir -p "${PYENV_ROOT}/shims"
+  touch "${PYENV_ROOT}/shims/oldshim1"
+  chmod +x "${PYENV_ROOT}/shims/oldshim1"
+
+  create_executable "2.0" "rake"
+  create_executable "2.0" "python"
+
+  run pyenv-rehash
+  assert_success ""
+
+  assert [ ! -e "${PYENV_ROOT}/shims/oldshim1" ]
+}
+
+@test "binary install locations containing spaces" {
+  create_executable "dirname1 p247" "python"
+  create_executable "dirname2 preview1" "rspec"
+
+  assert [ ! -e "${PYENV_ROOT}/shims/python" ]
+  assert [ ! -e "${PYENV_ROOT}/shims/rspec" ]
+
+  run pyenv-rehash
+  assert_success ""
+
+  run ls "${PYENV_ROOT}/shims"
+  assert_success
+  assert_output <<OUT
+rspec
+python
+OUT
+}
+
+@test "carries original IFS within hooks" {
+  hook_path="${PYENV_TEST_DIR}/pyenv.d"
+  mkdir -p "${hook_path}/rehash"
+  cat > "${hook_path}/rehash/hello.bash" <<SH
+hellos=(\$(printf "hello\\tugly world\\nagain"))
+echo HELLO="\$(printf ":%s" "\${hellos[@]}")"
+exit
+SH
+
+  PYENV_HOOK_PATH="$hook_path" IFS=$' \t\n' run pyenv-rehash
+  assert_success
+  assert_output "HELLO=:hello:ugly:world:again"
+}
+
+@test "sh-rehash in bash" {
+  create_executable "2.0" "python"
+  PYENV_SHELL=bash run pyenv-sh-rehash
+  assert_success "hash -r 2>/dev/null || true"
+  assert [ -x "${PYENV_ROOT}/shims/python" ]
+}
+
+@test "sh-rehash in fish" {
+  create_executable "2.0" "python"
+  PYENV_SHELL=fish run pyenv-sh-rehash
+  assert_success ""
+  assert [ -x "${PYENV_ROOT}/shims/python" ]
+}
diff --git a/test/shell.bats b/test/shell.bats
new file mode 100644
index 00000000..30bf127b
--- /dev/null
+++ b/test/shell.bats
@@ -0,0 +1,52 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "no shell version" {
+  mkdir -p "${PYENV_TEST_DIR}/myproject"
+  cd "${PYENV_TEST_DIR}/myproject"
+  echo "1.2.3" > .python-version
+  PYENV_VERSION="" run pyenv-sh-shell
+  assert_failure "pyenv: no shell-specific version configured"
+}
+
+@test "shell version" {
+  PYENV_SHELL=bash PYENV_VERSION="1.2.3" run pyenv-sh-shell
+  assert_success 'echo "$PYENV_VERSION"'
+}
+
+@test "shell version (fish)" {
+  PYENV_SHELL=fish PYENV_VERSION="1.2.3" run pyenv-sh-shell
+  assert_success 'echo "$PYENV_VERSION"'
+}
+
+@test "shell unset" {
+  PYENV_SHELL=bash run pyenv-sh-shell --unset
+  assert_success "unset PYENV_VERSION"
+}
+
+@test "shell unset (fish)" {
+  PYENV_SHELL=fish run pyenv-sh-shell --unset
+  assert_success "set -e PYENV_VERSION"
+}
+
+@test "shell change invalid version" {
+  run pyenv-sh-shell 1.2.3
+  assert_failure
+  assert_output <<SH
+pyenv: version \`1.2.3' not installed
+false
+SH
+}
+
+@test "shell change version" {
+  mkdir -p "${PYENV_ROOT}/versions/1.2.3"
+  PYENV_SHELL=bash run pyenv-sh-shell 1.2.3
+  assert_success 'export PYENV_VERSION="1.2.3"'
+}
+
+@test "shell change version (fish)" {
+  mkdir -p "${PYENV_ROOT}/versions/1.2.3"
+  PYENV_SHELL=fish run pyenv-sh-shell 1.2.3
+  assert_success 'setenv PYENV_VERSION "1.2.3"'
+}
diff --git a/test/shims.bats b/test/shims.bats
new file mode 100644
index 00000000..348125e4
--- /dev/null
+++ b/test/shims.bats
@@ -0,0 +1,29 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "no shims" {
+  run pyenv-shims
+  assert_success
+  assert [ -z "$output" ]
+}
+
+@test "shims" {
+  mkdir -p "${PYENV_ROOT}/shims"
+  touch "${PYENV_ROOT}/shims/python"
+  touch "${PYENV_ROOT}/shims/irb"
+  run pyenv-shims
+  assert_success
+  assert_line "${PYENV_ROOT}/shims/python"
+  assert_line "${PYENV_ROOT}/shims/irb"
+}
+
+@test "shims --short" {
+  mkdir -p "${PYENV_ROOT}/shims"
+  touch "${PYENV_ROOT}/shims/python"
+  touch "${PYENV_ROOT}/shims/irb"
+  run pyenv-shims --short
+  assert_success
+  assert_line "irb"
+  assert_line "python"
+}
diff --git a/test/test_helper.bash b/test/test_helper.bash
new file mode 100644
index 00000000..57f75ea3
--- /dev/null
+++ b/test/test_helper.bash
@@ -0,0 +1,95 @@
+unset PYENV_VERSION
+unset PYENV_DIR
+
+PYENV_TEST_DIR="${BATS_TMPDIR}/pyenv"
+
+# guard against executing this block twice due to bats internals
+if [ "$PYENV_ROOT" != "${PYENV_TEST_DIR}/root" ]; then
+  export PYENV_ROOT="${PYENV_TEST_DIR}/root"
+  export HOME="${PYENV_TEST_DIR}/home"
+
+  PATH=/usr/bin:/bin:/usr/sbin:/sbin
+  PATH="${PYENV_TEST_DIR}/bin:$PATH"
+  PATH="${BATS_TEST_DIRNAME}/../libexec:$PATH"
+  PATH="${BATS_TEST_DIRNAME}/libexec:$PATH"
+  PATH="${PYENV_ROOT}/shims:$PATH"
+  export PATH
+fi
+
+teardown() {
+  rm -rf "$PYENV_TEST_DIR"
+}
+
+flunk() {
+  { if [ "$#" -eq 0 ]; then cat -
+    else echo "$@"
+    fi
+  } | sed "s:${PYENV_TEST_DIR}:TEST_DIR:g" >&2
+  return 1
+}
+
+assert_success() {
+  if [ "$status" -ne 0 ]; then
+    flunk "command failed with exit status $status"
+  elif [ "$#" -gt 0 ]; then
+    assert_output "$1"
+  fi
+}
+
+assert_failure() {
+  if [ "$status" -eq 0 ]; then
+    flunk "expected failed exit status"
+  elif [ "$#" -gt 0 ]; then
+    assert_output "$1"
+  fi
+}
+
+assert_equal() {
+  if [ "$1" != "$2" ]; then
+    { echo "expected: $1"
+      echo "actual:   $2"
+    } | flunk
+  fi
+}
+
+assert_output() {
+  local expected
+  if [ $# -eq 0 ]; then expected="$(cat -)"
+  else expected="$1"
+  fi
+  assert_equal "$expected" "$output"
+}
+
+assert_line() {
+  if [ "$1" -ge 0 ] 2>/dev/null; then
+    assert_equal "$2" "${lines[$1]}"
+  else
+    local line
+    for line in "${lines[@]}"; do
+      if [ "$line" = "$1" ]; then return 0; fi
+    done
+    flunk "expected line \`$1'"
+  fi
+}
+
+refute_line() {
+  if [ "$1" -ge 0 ] 2>/dev/null; then
+    local num_lines="${#lines[@]}"
+    if [ "$1" -lt "$num_lines" ]; then
+      flunk "output has $num_lines lines"
+    fi
+  else
+    local line
+    for line in "${lines[@]}"; do
+      if [ "$line" = "$1" ]; then
+        flunk "expected to not find line \`$line'"
+      fi
+    done
+  fi
+}
+
+assert() {
+  if ! "$@"; then
+    flunk "failed: $@"
+  fi
+}
diff --git a/test/version-file-read.bats b/test/version-file-read.bats
new file mode 100644
index 00000000..c9d19e51
--- /dev/null
+++ b/test/version-file-read.bats
@@ -0,0 +1,66 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "${PYENV_TEST_DIR}/myproject"
+  cd "${PYENV_TEST_DIR}/myproject"
+}
+
+@test "fails without arguments" {
+  run pyenv-version-file-read
+  assert_failure ""
+}
+
+@test "fails for invalid file" {
+  run pyenv-version-file-read "non-existent"
+  assert_failure ""
+}
+
+@test "fails for blank file" {
+  echo > my-version
+  run pyenv-version-file-read my-version
+  assert_failure ""
+}
+
+@test "reads simple version file" {
+  cat > my-version <<<"1.9.3"
+  run pyenv-version-file-read my-version
+  assert_success "1.9.3"
+}
+
+@test "ignores leading spaces" {
+  cat > my-version <<<"  1.9.3"
+  run pyenv-version-file-read my-version
+  assert_success "1.9.3"
+}
+
+@test "reads only the first word from file" {
+  cat > my-version <<<"1.9.3-p194@tag 1.8.7 hi"
+  run pyenv-version-file-read my-version
+  assert_success "1.9.3-p194@tag"
+}
+
+@test "loads only the first line in file" {
+  cat > my-version <<IN
+1.8.7 one
+1.9.3 two
+IN
+  run pyenv-version-file-read my-version
+  assert_success "1.8.7"
+}
+
+@test "ignores leading blank lines" {
+  cat > my-version <<IN
+
+1.9.3
+IN
+  run pyenv-version-file-read my-version
+  assert_success "1.9.3"
+}
+
+@test "handles the file with no trailing newline" {
+  echo -n "1.8.7" > my-version
+  run pyenv-version-file-read my-version
+  assert_success "1.8.7"
+}
diff --git a/test/version-file-write.bats b/test/version-file-write.bats
new file mode 100644
index 00000000..be23bbb4
--- /dev/null
+++ b/test/version-file-write.bats
@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+@test "invocation without 2 arguments prints usage" {
+  run pyenv-version-file-write
+  assert_failure "Usage: pyenv version-file-write <file> <version>"
+  run pyenv-version-file-write "one" ""
+  assert_failure
+}
+
+@test "setting nonexistent version fails" {
+  assert [ ! -e ".python-version" ]
+  run pyenv-version-file-write ".python-version" "1.8.7"
+  assert_failure "pyenv: version \`1.8.7' not installed"
+  assert [ ! -e ".python-version" ]
+}
+
+@test "writes value to arbitrary file" {
+  mkdir -p "${PYENV_ROOT}/versions/1.8.7"
+  assert [ ! -e "my-version" ]
+  run pyenv-version-file-write "${PWD}/my-version" "1.8.7"
+  assert_success ""
+  assert [ "$(cat my-version)" = "1.8.7" ]
+}
diff --git a/test/version-file.bats b/test/version-file.bats
new file mode 100644
index 00000000..8ecf5b8a
--- /dev/null
+++ b/test/version-file.bats
@@ -0,0 +1,99 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+create_file() {
+  mkdir -p "$(dirname "$1")"
+  touch "$1"
+}
+
+@test "prints global file if no version files exist" {
+  assert [ ! -e "${PYENV_ROOT}/version" ]
+  assert [ ! -e ".python-version" ]
+  run pyenv-version-file
+  assert_success "${PYENV_ROOT}/version"
+}
+
+@test "detects 'global' file" {
+  create_file "${PYENV_ROOT}/global"
+  run pyenv-version-file
+  assert_success "${PYENV_ROOT}/global"
+}
+
+@test "detects 'default' file" {
+  create_file "${PYENV_ROOT}/default"
+  run pyenv-version-file
+  assert_success "${PYENV_ROOT}/default"
+}
+
+@test "'version' has precedence over 'global' and 'default'" {
+  create_file "${PYENV_ROOT}/version"
+  create_file "${PYENV_ROOT}/global"
+  create_file "${PYENV_ROOT}/default"
+  run pyenv-version-file
+  assert_success "${PYENV_ROOT}/version"
+}
+
+@test "in current directory" {
+  create_file ".python-version"
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/.python-version"
+}
+
+@test "legacy file in current directory" {
+  create_file ".pyenv-version"
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/.pyenv-version"
+}
+
+@test ".python-version has precedence over legacy file" {
+  create_file ".python-version"
+  create_file ".pyenv-version"
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/.python-version"
+}
+
+@test "in parent directory" {
+  create_file ".python-version"
+  mkdir -p project
+  cd project
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/.python-version"
+}
+
+@test "topmost file has precedence" {
+  create_file ".python-version"
+  create_file "project/.python-version"
+  cd project
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/project/.python-version"
+}
+
+@test "legacy file has precedence if higher" {
+  create_file ".python-version"
+  create_file "project/.pyenv-version"
+  cd project
+  run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/project/.pyenv-version"
+}
+
+@test "PYENV_DIR has precedence over PWD" {
+  create_file "widget/.python-version"
+  create_file "project/.python-version"
+  cd project
+  PYENV_DIR="${PYENV_TEST_DIR}/widget" run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/widget/.python-version"
+}
+
+@test "PWD is searched if PYENV_DIR yields no results" {
+  mkdir -p "widget/blank"
+  create_file "project/.python-version"
+  cd project
+  PYENV_DIR="${PYENV_TEST_DIR}/widget/blank" run pyenv-version-file
+  assert_success "${PYENV_TEST_DIR}/project/.python-version"
+}
diff --git a/test/version-name.bats b/test/version-name.bats
new file mode 100644
index 00000000..efbaa347
--- /dev/null
+++ b/test/version-name.bats
@@ -0,0 +1,65 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_version() {
+  mkdir -p "${PYENV_ROOT}/versions/$1"
+}
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+@test "no version selected" {
+  assert [ ! -d "${PYENV_ROOT}/versions" ]
+  run pyenv-version-name
+  assert_success "system"
+}
+
+@test "system version is not checked for existance" {
+  PYENV_VERSION=system run pyenv-version-name
+  assert_success "system"
+}
+
+@test "PYENV_VERSION has precedence over local" {
+  create_version "1.8.7"
+  create_version "1.9.3"
+
+  cat > ".python-version" <<<"1.8.7"
+  run pyenv-version-name
+  assert_success "1.8.7"
+
+  PYENV_VERSION=1.9.3 run pyenv-version-name
+  assert_success "1.9.3"
+}
+
+@test "local file has precedence over global" {
+  create_version "1.8.7"
+  create_version "1.9.3"
+
+  cat > "${PYENV_ROOT}/version" <<<"1.8.7"
+  run pyenv-version-name
+  assert_success "1.8.7"
+
+  cat > ".python-version" <<<"1.9.3"
+  run pyenv-version-name
+  assert_success "1.9.3"
+}
+
+@test "missing version" {
+  PYENV_VERSION=1.2 run pyenv-version-name
+  assert_failure "pyenv: version \`1.2' is not installed"
+}
+
+@test "version with prefix in name" {
+  create_version "1.8.7"
+  cat > ".python-version" <<<"python-1.8.7"
+  run pyenv-version-name
+  assert_success
+  assert_output <<OUT
+warning: ignoring extraneous \`python-' prefix in version \`python-1.8.7'
+         (set by ${PWD}/.python-version)
+1.8.7
+OUT
+}
diff --git a/test/version-origin.bats b/test/version-origin.bats
new file mode 100644
index 00000000..324b042e
--- /dev/null
+++ b/test/version-origin.bats
@@ -0,0 +1,38 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+@test "reports global file even if it doesn't exist" {
+  assert [ ! -e "${PYENV_ROOT}/version" ]
+  run pyenv-version-origin
+  assert_success "${PYENV_ROOT}/version"
+}
+
+@test "detects global file" {
+  mkdir -p "$PYENV_ROOT"
+  touch "${PYENV_ROOT}/version"
+  run pyenv-version-origin
+  assert_success "${PYENV_ROOT}/version"
+}
+
+@test "detects PYENV_VERSION" {
+  PYENV_VERSION=1 run pyenv-version-origin
+  assert_success "PYENV_VERSION environment variable"
+}
+
+@test "detects local file" {
+  touch .python-version
+  run pyenv-version-origin
+  assert_success "${PWD}/.python-version"
+}
+
+@test "detects alternate version file" {
+  touch .pyenv-version
+  run pyenv-version-origin
+  assert_success "${PWD}/.pyenv-version"
+}
diff --git a/test/version.bats b/test/version.bats
new file mode 100644
index 00000000..a26c1736
--- /dev/null
+++ b/test/version.bats
@@ -0,0 +1,38 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_version() {
+  mkdir -p "${PYENV_ROOT}/versions/$1"
+}
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+@test "no version selected" {
+  assert [ ! -d "${PYENV_ROOT}/versions" ]
+  run pyenv-version
+  assert_success "system (set by ${PYENV_ROOT}/version)"
+}
+
+@test "set by PYENV_VERSION" {
+  create_version "1.9.3"
+  PYENV_VERSION=1.9.3 run pyenv-version
+  assert_success "1.9.3 (set by PYENV_VERSION environment variable)"
+}
+
+@test "set by local file" {
+  create_version "1.9.3"
+  cat > ".python-version" <<<"1.9.3"
+  run pyenv-version
+  assert_success "1.9.3 (set by ${PWD}/.python-version)"
+}
+
+@test "set by global file" {
+  create_version "1.9.3"
+  cat > "${PYENV_ROOT}/version" <<<"1.9.3"
+  run pyenv-version
+  assert_success "1.9.3 (set by ${PYENV_ROOT}/version)"
+}
diff --git a/test/versions.bats b/test/versions.bats
new file mode 100644
index 00000000..44fad1de
--- /dev/null
+++ b/test/versions.bats
@@ -0,0 +1,115 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_version() {
+  mkdir -p "${PYENV_ROOT}/versions/$1"
+}
+
+setup() {
+  mkdir -p "$PYENV_TEST_DIR"
+  cd "$PYENV_TEST_DIR"
+}
+
+stub_system_python() {
+  local stub="${PYENV_TEST_DIR}/bin/python"
+  mkdir -p "$(dirname "$stub")"
+  touch "$stub" && chmod +x "$stub"
+}
+
+@test "no versions installed" {
+  stub_system_python
+  assert [ ! -d "${PYENV_ROOT}/versions" ]
+  run pyenv-versions
+  assert_success "* system (set by ${PYENV_ROOT}/version)"
+}
+
+@test "bare output no versions installed" {
+  assert [ ! -d "${PYENV_ROOT}/versions" ]
+  run pyenv-versions --bare
+  assert_success ""
+}
+
+@test "single version installed" {
+  stub_system_python
+  create_version "1.9"
+  run pyenv-versions
+  assert_success
+  assert_output <<OUT
+* system (set by ${PYENV_ROOT}/version)
+  1.9
+OUT
+}
+
+@test "single version bare" {
+  create_version "1.9"
+  run pyenv-versions --bare
+  assert_success "1.9"
+}
+
+@test "multiple versions" {
+  stub_system_python
+  create_version "1.8.7"
+  create_version "1.9.3"
+  create_version "2.0.0"
+  run pyenv-versions
+  assert_success
+  assert_output <<OUT
+* system (set by ${PYENV_ROOT}/version)
+  1.8.7
+  1.9.3
+  2.0.0
+OUT
+}
+
+@test "indicates current version" {
+  stub_system_python
+  create_version "1.9.3"
+  create_version "2.0.0"
+  PYENV_VERSION=1.9.3 run pyenv-versions
+  assert_success
+  assert_output <<OUT
+  system
+* 1.9.3 (set by PYENV_VERSION environment variable)
+  2.0.0
+OUT
+}
+
+@test "bare doesn't indicate current version" {
+  create_version "1.9.3"
+  create_version "2.0.0"
+  PYENV_VERSION=1.9.3 run pyenv-versions --bare
+  assert_success
+  assert_output <<OUT
+1.9.3
+2.0.0
+OUT
+}
+
+@test "globally selected version" {
+  stub_system_python
+  create_version "1.9.3"
+  create_version "2.0.0"
+  cat > "${PYENV_ROOT}/version" <<<"1.9.3"
+  run pyenv-versions
+  assert_success
+  assert_output <<OUT
+  system
+* 1.9.3 (set by ${PYENV_ROOT}/version)
+  2.0.0
+OUT
+}
+
+@test "per-project version" {
+  stub_system_python
+  create_version "1.9.3"
+  create_version "2.0.0"
+  cat > ".python-version" <<<"1.9.3"
+  run pyenv-versions
+  assert_success
+  assert_output <<OUT
+  system
+* 1.9.3 (set by ${PYENV_TEST_DIR}/.python-version)
+  2.0.0
+OUT
+}
diff --git a/test/whence.bats b/test/whence.bats
new file mode 100644
index 00000000..3c4d6b21
--- /dev/null
+++ b/test/whence.bats
@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_executable() {
+  local bin="${PYENV_ROOT}/versions/${1}/bin"
+  mkdir -p "$bin"
+  touch "${bin}/$2"
+  chmod +x "${bin}/$2"
+}
+
+@test "finds versions where present" {
+  create_executable "1.8" "python"
+  create_executable "1.8" "rake"
+  create_executable "2.0" "python"
+  create_executable "2.0" "rspec"
+
+  run pyenv-whence python
+  assert_success
+  assert_output <<OUT
+1.8
+2.0
+OUT
+
+  run pyenv-whence rake
+  assert_success "1.8"
+
+  run pyenv-whence rspec
+  assert_success "2.0"
+}
diff --git a/test/which.bats b/test/which.bats
new file mode 100644
index 00000000..2bf134c6
--- /dev/null
+++ b/test/which.bats
@@ -0,0 +1,74 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+create_executable() {
+  local bin
+  if [[ $1 == */* ]]; then bin="$1"
+  else bin="${PYENV_ROOT}/versions/${1}/bin"
+  fi
+  mkdir -p "$bin"
+  touch "${bin}/$2"
+  chmod +x "${bin}/$2"
+}
+
+@test "outputs path to executable" {
+  create_executable "1.8" "python"
+  create_executable "2.0" "rspec"
+
+  PYENV_VERSION=1.8 run pyenv-which python
+  assert_success "${PYENV_ROOT}/versions/1.8/bin/python"
+
+  PYENV_VERSION=2.0 run pyenv-which rspec
+  assert_success "${PYENV_ROOT}/versions/2.0/bin/rspec"
+}
+
+@test "searches PATH for system version" {
+  create_executable "${PYENV_TEST_DIR}/bin" "kill-all-humans"
+  create_executable "${PYENV_ROOT}/shims" "kill-all-humans"
+
+  PYENV_VERSION=system run pyenv-which kill-all-humans
+  assert_success "${PYENV_TEST_DIR}/bin/kill-all-humans"
+}
+
+@test "version not installed" {
+  create_executable "2.0" "rspec"
+  PYENV_VERSION=1.9 run pyenv-which rspec
+  assert_failure "pyenv: version \`1.9' is not installed"
+}
+
+@test "no executable found" {
+  create_executable "1.8" "rspec"
+  PYENV_VERSION=1.8 run pyenv-which rake
+  assert_failure "pyenv: rake: command not found"
+}
+
+@test "executable found in other versions" {
+  create_executable "1.8" "python"
+  create_executable "1.9" "rspec"
+  create_executable "2.0" "rspec"
+
+  PYENV_VERSION=1.8 run pyenv-which rspec
+  assert_failure
+  assert_output <<OUT
+pyenv: rspec: command not found
+
+The \`rspec' command exists in these Python versions:
+  1.9
+  2.0
+OUT
+}
+
+@test "carries original IFS within hooks" {
+  hook_path="${PYENV_TEST_DIR}/pyenv.d"
+  mkdir -p "${hook_path}/which"
+  cat > "${hook_path}/which/hello.bash" <<SH
+hellos=(\$(printf "hello\\tugly world\\nagain"))
+echo HELLO="\$(printf ":%s" "\${hellos[@]}")"
+exit
+SH
+
+  PYENV_HOOK_PATH="$hook_path" IFS=$' \t\n' run pyenv-which anything
+  assert_success
+  assert_output "HELLO=:hello:ugly:world:again"
+}