docs: move tmux documentation to its own file

2 files changed, 79 insertions, 74 deletions

diff --git a/internal/tmux/tmux.go b/internal/tmux/tmux.go
index 63b5660..6d75a44 100644
--- a/internal/tmux/tmux.go
+++ b/internal/tmux/tmux.go
@@ -1,18 +1,20 @@
 package tmux
 
 import (
-    "os"
-    "os/exec"
-    "strconv"
-    "strings"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
 )
 
 // Available reports whether tmux is available and we appear to be in a tmux session.
 func Available() bool { return HasBinary() && InSession() }
 
 // HasBinary reports whether the tmux binary is on PATH.
-var lookPath = exec.LookPath
-var command = exec.Command
+var (
+	lookPath = exec.LookPath
+	command  = exec.Command
+)
 
 func HasBinary() bool { _, err := lookPath("tmux"); return err == nil }
 
@@ -47,8 +49,8 @@ func SplitRun(opts SplitOpts, argv []string) error {
 	// tmux takes a single command string. Use a conservative shell join.
 	cmdStr := shellJoin(argv)
 	args = append(args, cmdStr)
-    c := command("tmux", args...)
-    return c.Run()
+	c := command("tmux", args...)
+	return c.Run()
 }
 
 // shellJoin quotes argv elements for safe use in a single shell command string.
diff --git a/internal/tmux/tmux_test.go b/internal/tmux/tmux_test.go
index b18c8a3..4db2e4a 100644
--- a/internal/tmux/tmux_test.go
+++ b/internal/tmux/tmux_test.go
@@ -1,82 +1,85 @@
 package tmux
 
 import (
-    "errors"
-    "os"
-    "os/exec"
-    "testing"
+	"errors"
+	"os"
+	"os/exec"
+	"testing"
 )
 
 func TestInSession(t *testing.T) {
-    t.Setenv("TMUX", "/tmp/tmux-123,123,0")
-    if !InSession() {
-        t.Fatal("expected InSession true when TMUX is set")
-    }
-    t.Setenv("TMUX", "")
-    if InSession() {
-        t.Fatal("expected InSession false when TMUX is empty")
-    }
+	t.Setenv("TMUX", "/tmp/tmux-123,123,0")
+	if !InSession() {
+		t.Fatal("expected InSession true when TMUX is set")
+	}
+	t.Setenv("TMUX", "")
+	if InSession() {
+		t.Fatal("expected InSession false when TMUX is empty")
+	}
 }
 
 func TestHasBinary_UsesLookPath(t *testing.T) {
-    old := lookPath
-    t.Cleanup(func() { lookPath = old })
-    lookPath = func(file string) (string, error) { return "/bin/tmux", nil }
-    if !HasBinary() {
-        t.Fatal("expected HasBinary true when lookPath succeeds")
-    }
-    lookPath = func(file string) (string, error) { return "", errors.New("nope") }
-    if HasBinary() {
-        t.Fatal("expected HasBinary false when lookPath fails")
-    }
+	old := lookPath
+	t.Cleanup(func() { lookPath = old })
+	lookPath = func(file string) (string, error) { return "/bin/tmux", nil }
+	if !HasBinary() {
+		t.Fatal("expected HasBinary true when lookPath succeeds")
+	}
+	lookPath = func(file string) (string, error) { return "", errors.New("nope") }
+	if HasBinary() {
+		t.Fatal("expected HasBinary false when lookPath fails")
+	}
 }
 
 func TestSplitRun_AssemblesArgs(t *testing.T) {
-    captured := struct{ name string; args []string }{}
-    oldCmd := command
-    t.Cleanup(func() { command = oldCmd })
-    command = func(name string, args ...string) *exec.Cmd {
-        captured.name = name
-        captured.args = append([]string(nil), args...)
-        // Use a benign command that exits 0
-        return exec.Command("true")
-    }
-    opts := SplitOpts{Target: ":.", Vertical: true, Percent: 40}
-    argv := []string{"/path/to/bin", "-flag", "value with spaces", "and'quote"}
-    if err := SplitRun(opts, argv); err != nil {
-        t.Fatalf("SplitRun error: %v", err)
-    }
-    if captured.name != "tmux" {
-        t.Fatalf("expected tmux, got %q", captured.name)
-    }
-    wantFlags := map[string]bool{"split-window": true, "-v": true, "-p": true, "40": true, "-t": true, ":.": true}
-    for _, a := range captured.args[:len(captured.args)-1] {
-        if wantFlags[a] {
-            delete(wantFlags, a)
-        }
-    }
-    if len(wantFlags) != 0 {
-        t.Fatalf("missing expected flags: %v", wantFlags)
-    }
-    last := captured.args[len(captured.args)-1]
-    if last == "" || last == argv[0] {
-        t.Fatalf("expected last arg to be joined command string, got %q", last)
-    }
-    _ = os.Unsetenv("TMUX")
+	captured := struct {
+		name string
+		args []string
+	}{}
+	oldCmd := command
+	t.Cleanup(func() { command = oldCmd })
+	command = func(name string, args ...string) *exec.Cmd {
+		captured.name = name
+		captured.args = append([]string(nil), args...)
+		// Use a benign command that exits 0
+		return exec.Command("true")
+	}
+	opts := SplitOpts{Target: ":.", Vertical: true, Percent: 40}
+	argv := []string{"/path/to/bin", "-flag", "value with spaces", "and'quote"}
+	if err := SplitRun(opts, argv); err != nil {
+		t.Fatalf("SplitRun error: %v", err)
+	}
+	if captured.name != "tmux" {
+		t.Fatalf("expected tmux, got %q", captured.name)
+	}
+	wantFlags := map[string]bool{"split-window": true, "-v": true, "-p": true, "40": true, "-t": true, ":.": true}
+	for _, a := range captured.args[:len(captured.args)-1] {
+		if wantFlags[a] {
+			delete(wantFlags, a)
+		}
+	}
+	if len(wantFlags) != 0 {
+		t.Fatalf("missing expected flags: %v", wantFlags)
+	}
+	last := captured.args[len(captured.args)-1]
+	if last == "" || last == argv[0] {
+		t.Fatalf("expected last arg to be joined command string, got %q", last)
+	}
+	_ = os.Unsetenv("TMUX")
 }
 
 func TestAvailable(t *testing.T) {
-    oldLook := lookPath
-    t.Cleanup(func() { lookPath = oldLook })
-    // Present binary + TMUX set -> available
-    lookPath = func(file string) (string, error) { return "/bin/tmux", nil }
-    t.Setenv("TMUX", "/tmp/tmux-1,1,1")
-    if !Available() {
-        t.Fatal("expected Available true with TMUX + binary")
-    }
-    // No binary -> not available
-    lookPath = func(file string) (string, error) { return "", errors.New("nope") }
-    if Available() {
-        t.Fatal("expected Available false without binary")
-    }
+	oldLook := lookPath
+	t.Cleanup(func() { lookPath = oldLook })
+	// Present binary + TMUX set -> available
+	lookPath = func(file string) (string, error) { return "/bin/tmux", nil }
+	t.Setenv("TMUX", "/tmp/tmux-1,1,1")
+	if !Available() {
+		t.Fatal("expected Available true with TMUX + binary")
+	}
+	// No binary -> not available
+	lookPath = func(file string) (string, error) { return "", errors.New("nope") }
+	if Available() {
+		t.Fatal("expected Available false without binary")
+	}
 }