test: high-level CLI tests that catch basic errors

test/cli.bats

+#!/usr/bin/env bats
+#
+# This tests the basic CLI functionality of Packer. It makes no network
+# requests and should be very fast.
+
+load test_helper
+
+@test "cli: packer should show help" {
+    run packer
+    [ "$status" -eq 1 ]
+    [[ "$output" == *"usage: packer"* ]]
+}
+
+@test "cli: packer version" {
+    run packer version
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Packer v"* ]]
+
+    run packer -v
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Packer v"* ]]
+
+    run packer --version
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"Packer v"* ]]
+}
+
+@test "cli: packer version show help" {
+    run packer version -h
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"usage: packer version"* ]]
+
+    run packer version --help
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"usage: packer version"* ]]
+}