test(acp): isolate wrapper env and cover codex dispatch

Author: wesm

internal/agent/acp_script_test.go

@@ -2,6 +2,7 @@ package agent
 
 import (
 	"bytes"
+	"fmt"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -31,9 +32,26 @@ func runACPWrapperCommand(t *testing.T, commandPath string, env map[string]strin
 	t.Helper()
 
 	cmd := exec.Command(commandPath, args...)
-	cmd.Env = os.Environ()
+	pathValue := os.Getenv("PATH")
+	if customPath, ok := env["PATH"]; ok {
+		pathValue = customPath
+	}
+
+	cmd.Env = []string{
+		"PATH=" + pathValue,
+	}
+	if home := os.Getenv("HOME"); home != "" {
+		cmd.Env = append(cmd.Env, "HOME="+home)
+	}
+	if tmpDir := os.Getenv("TMPDIR"); tmpDir != "" {
+		cmd.Env = append(cmd.Env, "TMPDIR="+tmpDir)
+	}
+
 	for k, v := range env {
-		cmd.Env = append(cmd.Env, k+"="+v)
+		if k == "PATH" {
+			continue
+		}
+		cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", k, v))
 	}
 
 	var stdout bytes.Buffer
@@ -86,6 +104,37 @@ func TestACPWrapperScripts(t *testing.T) {
 		}
 	})
 
+	t.Run("Adapter dispatch invokes codex wrapper binary from PATH", func(t *testing.T) {
+		fakeBinDir := t.TempDir()
+		writeACPTestCommand(t, fakeBinDir, "codex-acp", "#!/bin/sh\necho ACP_CODEX_OK\n")
+
+		stdout, stderr, err := runACPWrapperCommand(t, filepath.Join(scriptsDir, "acp-agent"), map[string]string{
+			"ROBOREV_ACP_ADAPTER": "codex",
+			"PATH":                fakeBinDir + string(os.PathListSeparator) + basePath,
+		})
+		if err != nil {
+			t.Fatalf("expected codex adapter dispatch to succeed, got err=%v stderr=%q", err, stderr)
+		}
+		if !strings.Contains(stdout, "ACP_CODEX_OK") {
+			t.Fatalf("expected codex marker in stdout, got: %q", stdout)
+		}
+	})
+
+	t.Run("Default adapter dispatch uses codex when adapter env is unset", func(t *testing.T) {
+		fakeBinDir := t.TempDir()
+		writeACPTestCommand(t, fakeBinDir, "codex-acp", "#!/bin/sh\necho ACP_DEFAULT_CODEX_OK\n")
+
+		stdout, stderr, err := runACPWrapperCommand(t, filepath.Join(scriptsDir, "acp-agent"), map[string]string{
+			"PATH": fakeBinDir + string(os.PathListSeparator) + basePath,
+		})
+		if err != nil {
+			t.Fatalf("expected default adapter dispatch to succeed, got err=%v stderr=%q", err, stderr)
+		}
+		if !strings.Contains(stdout, "ACP_DEFAULT_CODEX_OK") {
+			t.Fatalf("expected default codex marker in stdout, got: %q", stdout)
+		}
+	})
+
 	t.Run("Gemini wrapper appends --experimental-acp flag", func(t *testing.T) {
 		fakeBinDir := t.TempDir()
 		writeACPTestCommand(t, fakeBinDir, "gemini", "#!/bin/sh\necho GEMINI_ARGS:$@\n")