mesh-host/cmd/mesh-bootstrap/main_test.go

package main

import (
	"flag"
	"strings"
	"testing"
	"time"

	"github.com/novox/mesh-host/internal/bootstrap"
	"github.com/novox/mesh-host/internal/store"
)

// Argument handling gets tests for the reason `mesh-host` records: the standard library stops
// parsing at the first non-flag argument, so a flag sitting after one is silently dropped and the
// command exits zero having ignored what it was asked. Here that would mean `--dry-run` ignored on
// a program whose whole job is to change a machine.

func TestBootstrapIsWhatItDoesWithNoCommand(t *testing.T) {
	// Running the installer with nothing but flags must install, not print usage: the command is
	// the reason the binary exists, and making somebody type its name twice buys nothing.
	command, opts, _, err := parseArgs([]string{"--dry-run"})
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if command != "bootstrap" {
		t.Errorf("command = %q, want bootstrap", command)
	}
	if !opts.DryRun {
		t.Error("--dry-run before any subcommand was ignored")
	}
}

func TestFlagsAreReadWhereverTheySit(t *testing.T) {
	for _, args := range [][]string{
		{"bootstrap", "--dry-run", "--bundle", "s.lock", "--json"},
		{"bootstrap", "--json", "--bundle=s.lock", "--dry-run"},
		{"--bundle", "s.lock", "--dry-run", "--json"},
	} {
		_, opts, jsonOut, err := parseArgs(args)
		if err != nil {
			t.Errorf("%v: unexpected error: %v", args, err)
			continue
		}
		if !opts.DryRun || !jsonOut || opts.Template != "s.lock" {
			t.Errorf("%v parsed as dry-run=%v json=%v bundle=%q",
				args, opts.DryRun, jsonOut, opts.Template)
		}
	}
}

func TestAMistypedFlagIsRefusedNotIgnored(t *testing.T) {
	// Asymmetric cost: an error is a moment's annoyance, and a silently dropped --dry-run is a
	// machine changed by somebody who asked for it not to be.
	if _, _, _, err := parseArgs([]string{"bootstrap", "--dry-runn"}); err == nil {
		t.Fatal("a mistyped flag was accepted")
	}
}

func TestAnUnexpectedArgumentIsRefused(t *testing.T) {
	if _, _, _, err := parseArgs([]string{"bootstrap", "substrate.lock"}); err == nil {
		t.Fatal("a stray argument was ignored rather than refused — the bundle is --bundle")
	}
}

func TestTheDefaultsAreTheDocumentedOnes(t *testing.T) {
	// The usage text is a promise. A default that drifts from what is printed is a small lie that
	// costs somebody an afternoon in front of a machine that will not come up.
	_, opts, jsonOut, err := parseArgs(nil)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if opts.Template != defaultTemplate {
		t.Errorf("default bundle is %q; the usage text says %q", opts.Template, defaultTemplate)
	}
	if opts.Out != defaultOut {
		t.Errorf("default out is %q; the usage text says %q", opts.Out, defaultOut)
	}
	if opts.State != store.DefaultPath {
		t.Errorf("default state is %q; the host's own default is %q", opts.State, store.DefaultPath)
	}
	if opts.Timeout != 30*time.Second {
		t.Errorf("default timeout is %s; the usage text says 30s", opts.Timeout)
	}
	if opts.Wait != 3*time.Minute {
		t.Errorf("default wait is %s; the usage text says 3m", opts.Wait)
	}
	if opts.DryRun || jsonOut || opts.System != "" {
		t.Error("something is on by default that the usage text describes as a flag")
	}
}

// Every flag the usage text promises must exist, and every flag that exists must be in the usage
// text. The two drifting apart is how a program acquires a feature nobody can find and a
// documented option that does nothing.
func TestTheUsageTextAndTheFlagsAgree(t *testing.T) {
	var opts bootstrap.Options
	var jsonOut bool
	set := newFlagSet(&opts, &jsonOut)

	declared := map[string]bool{}
	set.VisitAll(func(f *flag.Flag) { declared[f.Name] = true })

	for name := range declared {
		if !strings.Contains(usage, "--"+name) {
			t.Errorf("--%s exists and the usage text does not mention it", name)
		}
	}
	for _, promised := range []string{"bundle", "out", "state", "system", "timeout", "wait", "dry-run", "json"} {
		if !declared[promised] {
			t.Errorf("the usage text promises --%s and no such flag exists", promised)
		}
	}
}