feat: «Здесь» from a machine's file pane opens the terminal in that pane's folder (the agent starts the shell there; an older agent, or a folder gone, at home)

internal/agent/terminal_test.go

@@ -0,0 +1,62 @@
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// A terminal opened with a folder starts its shell there; a folder that is
+// not there leaves it at home.
+func TestStartPTYDir(t *testing.T) {
+	dir, err := filepath.EvalSymlinks(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	sub := filepath.Join(dir, "sub dir")
+	if err := os.Mkdir(sub, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if got := ptyPwd(t, sub); got != sub {
+		t.Fatalf("pwd = %q, want %q", got, sub)
+	}
+	home, _ := filepath.EvalSymlinks(homeDir(""))
+	if got := ptyPwd(t, filepath.Join(dir, "missing")); got != home {
+		t.Fatalf("pwd for a missing folder = %q, want home %q", got, home)
+	}
+}
+
+// ptyPwd opens a terminal at dir and returns where its shell is.
+func ptyPwd(t *testing.T, dir string) string {
+	t.Helper()
+	t.Setenv("SHELL", "/bin/sh")
+	p, err := StartPTY("", dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer p.Close()
+	if _, err := p.Write([]byte("echo \"@@$(pwd -P)@@\"\n")); err != nil {
+		t.Fatal(err)
+	}
+	var out strings.Builder
+	buf := make([]byte, 4096)
+	deadline := time.Now().Add(5 * time.Second)
+	for time.Now().Before(deadline) {
+		n, err := p.Read(buf)
+		out.Write(buf[:n])
+		s := out.String()
+		// The echoed command line has "@@$(pwd" in it; the answer does not.
+		for _, part := range strings.Split(s, "@@") {
+			if strings.HasPrefix(part, "/") && strings.Contains(s, part+"@@") {
+				return part
+			}
+		}
+		if err != nil {
+			break
+		}
+	}
+	t.Fatalf("no pwd in %q", out.String())
+	return ""
+}