1 files changed, 170 insertions, 0 deletions
diff --git a/internal/tmuxedit/send_test.go b/internal/tmuxedit/send_test.go
new file mode 100644
index 0000000..eeced35
--- /dev/null
+++ b/internal/tmuxedit/send_test.go
@@ -0,0 +1,170 @@
+package tmuxedit
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+)
+
+func TestDeduplicateText(t *testing.T) {
+	tests := []struct {
+		name     string
+		original string
+		edited   string
+		want     string
+	}{
+		{"empty both", "", "", ""},
+		{"empty original", "", "new text", "new text"},
+		{"empty edited", "original", "", ""},
+		{"unchanged", "hello world", "hello world", ""},
+		{"appended", "hello", "hello world", "world"},
+		{"rewritten", "hello world", "goodbye world", "goodbye world"},
+		{"whitespace handling", "  hello  ", "  hello  world  ", "world"},
+		{"prefix match with newlines", "line1\nline2", "line1\nline2\nline3", "line3"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := deduplicateText(tt.original, tt.edited)
+			if got != tt.want {
+				t.Errorf("deduplicateText(%q, %q) = %q, want %q",
+					tt.original, tt.edited, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestSendTextToPane_SingleLine(t *testing.T) {
+	var calls []string
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		calls = append(calls, fmt.Sprintf("send:%s:%s", paneID, strings.Join(keys, ",")))
+		return nil
+	}
+	agent := AgentConfig{ClearFirst: true, ClearKeys: "C-u", NewlineKeys: "S-Enter"}
+	err := sendTextToPane("%5", "hello", agent)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// Expect: clear, then single line (no newline after last line)
+	if len(calls) != 2 {
+		t.Fatalf("got %d calls, want 2: %v", len(calls), calls)
+	}
+	if calls[0] != "send:%5:C-u" {
+		t.Errorf("call[0] = %q, want clear", calls[0])
+	}
+	if calls[1] != "send:%5:hello" {
+		t.Errorf("call[1] = %q, want text", calls[1])
+	}
+}
+
+func TestSendTextToPane_MultiLine(t *testing.T) {
+	var calls []string
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		calls = append(calls, strings.Join(keys, ","))
+		return nil
+	}
+	agent := AgentConfig{NewlineKeys: "S-Enter"}
+	err := sendTextToPane("%1", "line1\nline2\nline3", agent)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// Expect: line1, S-Enter, line2, S-Enter, line3 (no trailing newline)
+	want := []string{"line1", "S-Enter", "line2", "S-Enter", "line3"}
+	if len(calls) != len(want) {
+		t.Fatalf("got %d calls, want %d: %v", len(calls), len(want), calls)
+	}
+	for i, w := range want {
+		if calls[i] != w {
+			t.Errorf("call[%d] = %q, want %q", i, calls[i], w)
+		}
+	}
+}
+
+func TestSendTextToPane_NoClear(t *testing.T) {
+	var calls []string
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		calls = append(calls, strings.Join(keys, ","))
+		return nil
+	}
+	agent := AgentConfig{ClearFirst: false, ClearKeys: "C-u"}
+	err := sendTextToPane("%1", "hello", agent)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// No clear call; just the text
+	if len(calls) != 1 {
+		t.Fatalf("got %d calls, want 1: %v", len(calls), calls)
+	}
+}
+
+func TestSendTextToPane_Empty(t *testing.T) {
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(string, ...string) error {
+		t.Fatal("sendKeys should not be called for empty text")
+		return nil
+	}
+	err := sendTextToPane("%1", "", AgentConfig{})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestSendTextToPane_ClearError(t *testing.T) {
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		return fmt.Errorf("tmux error")
+	}
+	agent := AgentConfig{ClearFirst: true, ClearKeys: "C-u"}
+	err := sendTextToPane("%1", "hello", agent)
+	if err == nil {
+		t.Fatal("expected error on clear failure")
+	}
+}
+
+func TestSendTextToPane_SendError(t *testing.T) {
+	callCount := 0
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		callCount++
+		if callCount == 2 { // fail on second call (first line text)
+			return fmt.Errorf("send failed")
+		}
+		return nil
+	}
+	agent := AgentConfig{ClearFirst: true, ClearKeys: "C-u"}
+	err := sendTextToPane("%1", "hello", agent)
+	if err == nil {
+		t.Fatal("expected error on send failure")
+	}
+}
+
+func TestSendTextToPane_FallbackNewline(t *testing.T) {
+	var calls []string
+	oldSend := sendKeys
+	defer func() { sendKeys = oldSend }()
+	sendKeys = func(paneID string, keys ...string) error {
+		calls = append(calls, strings.Join(keys, ","))
+		return nil
+	}
+	// Agent with empty NewlineKeys should fallback to "Enter"
+	agent := AgentConfig{NewlineKeys: ""}
+	err := sendTextToPane("%1", "a\nb", agent)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// Expect: a, Enter, b
+	if len(calls) != 3 {
+		t.Fatalf("got %d calls, want 3: %v", len(calls), calls)
+	}
+	if calls[1] != "Enter" {
+		t.Errorf("newline key = %q, want Enter (fallback)", calls[1])
+	}
+}