Add functional test harness for fzshell binary

tests/functional/suite_test.go

@@ -0,0 +1,150 @@
+package functional_test
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+var (
+	fzshellBinary string
+	repoRoot      string
+)
+
+func TestMain(m *testing.M) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to get working directory: %v\n", err)
+		os.Exit(1)
+	}
+
+	repoRoot = filepath.Dir(filepath.Dir(cwd))
+
+	tempDir, err := os.MkdirTemp("", "fzshell-build-")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to create temp dir: %v\n", err)
+		os.Exit(1)
+	}
+
+	binaryPath := filepath.Join(tempDir, "fzshell")
+	buildCmd := exec.Command("go", "build", "-o", binaryPath, "./cmd/fzshell")
+	buildCmd.Dir = repoRoot
+	buildCmd.Stdout = os.Stdout
+	buildCmd.Stderr = os.Stderr
+	buildCmd.Env = os.Environ()
+
+	if err := buildCmd.Run(); err != nil {
+		fmt.Fprintf(os.Stderr, "go build failed: %v\n", err)
+		os.Exit(1)
+	}
+
+	fzshellBinary = binaryPath
+
+	exitCode := m.Run()
+
+	os.RemoveAll(tempDir)
+
+	os.Exit(exitCode)
+}
+
+type CommandResult struct {
+	Stdout   string
+	Stderr   string
+	ExitCode int
+}
+
+func runFzshell(t *testing.T, args []string, stdin string, env map[string]string) CommandResult {
+	t.Helper()
+
+	if fzshellBinary == "" {
+		t.Fatal("fzshell binary not built")
+	}
+
+	if repoRoot == "" {
+		t.Fatal("repository root not configured")
+	}
+
+	cmd := exec.Command(fzshellBinary, args...)
+	cmd.Dir = repoRoot
+
+	runtimeDir := t.TempDir()
+
+	envVars := environmentMap(os.Environ())
+
+	defaults := map[string]string{
+		"FZSHELL_DEBUG":   "1",
+		"XDG_RUNTIME_DIR": runtimeDir,
+	}
+
+	for key, value := range defaults {
+		if env != nil {
+			if _, ok := env[key]; ok {
+				continue
+			}
+		}
+		envVars[key] = value
+	}
+
+	for key, value := range env {
+		envVars[key] = value
+	}
+
+	cmd.Env = mapToEnvList(envVars)
+
+	var stdoutBuf bytes.Buffer
+	var stderrBuf bytes.Buffer
+
+	cmd.Stdout = &stdoutBuf
+	cmd.Stderr = &stderrBuf
+
+	if stdin != "" {
+		cmd.Stdin = strings.NewReader(stdin)
+	}
+
+	err := cmd.Run()
+
+	exitCode := 0
+	if err != nil {
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			exitCode = exitErr.ExitCode()
+		} else {
+			t.Fatalf("failed to run fzshell: %v", err)
+		}
+	}
+
+	return CommandResult{
+		Stdout:   stdoutBuf.String(),
+		Stderr:   stderrBuf.String(),
+		ExitCode: exitCode,
+	}
+}
+
+func environmentMap(env []string) map[string]string {
+	result := make(map[string]string, len(env))
+	for _, entry := range env {
+		if entry == "" {
+			continue
+		}
+
+		parts := strings.SplitN(entry, "=", 2)
+		key := parts[0]
+		value := ""
+		if len(parts) == 2 {
+			value = parts[1]
+		}
+		result[key] = value
+	}
+	return result
+}
+
+func mapToEnvList(env map[string]string) []string {
+	result := make([]string, 0, len(env))
+	for key, value := range env {
+		result = append(result, fmt.Sprintf("%s=%s", key, value))
+	}
+	return result
+}