integration: backfill CLI command coverage

Regroup the CLI tests into per-command files and cover every command
except debug/config with CRUD, flag and error permutations, asserted as
JSON.

integration/cli_server_test.go

@@ -0,0 +1,47 @@
+package integration
+
+import (
+	"testing"
+
+	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
+	"github.com/juanfont/headscale/hscontrol/types"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestServerInfoCommands covers the standalone server/info commands that do not
+// fit the resource CRUD groups: `health`, `version` and
+// `generate private-key`. They are exercised against a populated server (one
+// user with a node) so `health` reports a real, connected database.
+func TestServerInfoCommands(t *testing.T) {
+	IntegrationSkip(t)
+
+	scenario, headscale := setupCLIScenario(t, "cli-serverinfo", []string{"user1"}, 1)
+	defer scenario.ShutdownAssertNoPanics(t)
+
+	t.Run("health", func(t *testing.T) {
+		health := assertJSONRoundtrip[*v1.HealthResponse](t, headscale, []string{
+			"headscale", "health", "--output", "json",
+		})
+		assert.True(t, health.GetDatabaseConnectivity(), "database should be reachable")
+	})
+
+	t.Run("version", func(t *testing.T) {
+		info := assertJSONRoundtrip[types.VersionInfo](t, headscale, []string{
+			"headscale", "version", "--output", "json",
+		})
+		assert.NotEmpty(t, info.Version, "version string should be populated")
+		assert.NotEmpty(t, info.Go.Version, "go version should be populated")
+	})
+
+	t.Run("generate-private-key", func(t *testing.T) {
+		key := assertJSONRoundtrip[map[string]string](t, headscale, []string{
+			"headscale", "generate", "private-key", "--output", "json",
+		})
+
+		priv, ok := key["private_key"]
+		require.True(t, ok, "output should contain a private_key field")
+		assert.NotEmpty(t, priv, "generated private key should not be empty")
+		assert.Contains(t, priv, "privkey:", "machine private key should carry the privkey: prefix")
+	})
+}