add hexai-tmux-edit: tmux popup editor for AI agent prompts

New tool that opens $EDITOR in a tmux popup for composing longer prompts
when working with AI CLI agents (Claude Code, Cursor, Amp, Aider, etc.).
Captures existing prompt text from the target pane, pre-fills the editor,
and sends edited text back via tmux send-keys. Config-driven agent
detection via regex patterns in [tmux_edit] config section.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/internal/tmuxedit/pane_test.go b/internal/tmuxedit/pane_test.go
new file mode 100644
index 0000000..5b6f1b6
--- /dev/null
+++ b/internal/tmuxedit/pane_test.go
@@ -0,0 +1,83 @@
+package tmuxedit
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestResolveTargetPane_FlagWins(t *testing.T) {
+	old := runCommand
+	defer func() { runCommand = old }()
+	runCommand = func(string, ...string) ([]byte, error) {
+		return []byte("%99"), nil
+	}
+	t.Setenv("HEXAI_TMUX_PANE", "%10")
+	got, err := resolveTargetPane("%5")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "%5" {
+		t.Errorf("got %q, want %%5 (flag should win)", got)
+	}
+}
+
+func TestResolveTargetPane_EnvFallback(t *testing.T) {
+	old := runCommand
+	defer func() { runCommand = old }()
+	runCommand = func(string, ...string) ([]byte, error) {
+		return []byte("%99"), nil
+	}
+	t.Setenv("HEXAI_TMUX_PANE", "%10")
+	got, err := resolveTargetPane("")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "%10" {
+		t.Errorf("got %q, want %%10 (env fallback)", got)
+	}
+}
+
+func TestResolveTargetPane_TmuxQuery(t *testing.T) {
+	old := runCommand
+	defer func() { runCommand = old }()
+	runCommand = func(name string, args ...string) ([]byte, error) {
+		if name == "tmux" && len(args) > 0 && args[0] == "display-message" {
+			return []byte("%42\n"), nil
+		}
+		return nil, fmt.Errorf("unexpected command: %s", name)
+	}
+	t.Setenv("HEXAI_TMUX_PANE", "")
+	got, err := resolveTargetPane("")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "%42" {
+		t.Errorf("got %q, want %%42 (tmux query)", got)
+	}
+}
+
+func TestResolveTargetPane_TmuxError(t *testing.T) {
+	old := runCommand
+	defer func() { runCommand = old }()
+	runCommand = func(string, ...string) ([]byte, error) {
+		return nil, fmt.Errorf("tmux not available")
+	}
+	t.Setenv("HEXAI_TMUX_PANE", "")
+	_, err := resolveTargetPane("")
+	if err == nil {
+		t.Fatal("expected error when tmux fails")
+	}
+}
+
+func TestResolveTargetPane_TmuxEmptyOutput(t *testing.T) {
+	old := runCommand
+	defer func() { runCommand = old }()
+	runCommand = func(string, ...string) ([]byte, error) {
+		return []byte("  \n"), nil
+	}
+	t.Setenv("HEXAI_TMUX_PANE", "")
+	_, err := resolveTargetPane("")
+	if err == nil {
+		t.Fatal("expected error for empty tmux output")
+	}
+}