Import tests from rbenv with sed -e s/rbenv/pyenv/g

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" ]
+}