add a basic test for the inspect command

command/exec_test.go

@@ -85,6 +85,8 @@ func TestHelperProcess(*testing.T) {
 	switch cmd {
 	case "console":
 		os.Exit((&ConsoleCommand{Meta: commandMeta()}).Run(args))
+	case "inspect":
+		os.Exit((&InspectCommand{Meta: commandMeta()}).Run(args))
 	default:
 		fmt.Fprintf(os.Stderr, "Unknown command %q\n", cmd)
 		os.Exit(2)

command/inspect_test.go

@@ -1 +1,57 @@
 package command
+
+import (
+	"fmt"
+	"path/filepath"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func Test_commands(t *testing.T) {
+
+	tc := []struct {
+		command  []string
+		env      []string
+		expected string
+	}{
+		{[]string{"inspect", "-var=fruit=banana", filepath.Join(testFixture("var-arg"), "fruit_builder.pkr.hcl")}, nil, `Packer Inspect: HCL2 mode
+
+> input-variables:
+
+var.fruit: "banana" [debug: {Type:cty.String,CmdValue:banana,VarfileValue:null,EnvValue:null,DefaultValue:null}]
+
+> local-variables:
+
+local.fruit: "banana"
+
+> builds:
+
+  > <unnamed build 0>:
+
+    provisioners:
+
+      shell-local
+
+    post-processors:
+
+      <no post-processor>
+
+`},
+	}
+
+	for _, tc := range tc {
+		t.Run(fmt.Sprintf("packer %s", tc.command), func(t *testing.T) {
+			p := helperCommand(t, tc.command...)
+			p.Env = append(p.Env, tc.env...)
+			bs, err := p.Output()
+			if err != nil {
+				t.Fatalf("%v: %s", err, bs)
+			}
+			actual := string(bs)
+			if diff := cmp.Diff(tc.expected, actual); diff != "" {
+				t.Fatalf("unexpected ouput %s", diff)
+			}
+		})
+	}
+}