chore(ansi): add a few more Cut test cases

ansi/truncate.go

@@ -7,21 +7,21 @@ import (
 	"github.com/rivo/uniseg"
 )
 
-// Cut the string, without adding any prefix or tail strings.
-// This function is aware of ANSI escape codes and will not break them, and
-// accounts for wide-characters (such as East Asians and emojis).
-// Note that the [left] parameter is inclusive, while [right] isn't.
+// Cut the string, without adding any prefix or tail strings. This function is
+// aware of ANSI escape codes and will not break them, and accounts for
+// wide-characters (such as East-Asian characters and emojis). Note that the
+// [left] parameter is inclusive, while [right] isn't.
 func Cut(s string, left, right int) string {
 	if left == 0 {
 		return Truncate(s, right, "")
 	}
 	return TruncateLeft(Truncate(s, right, ""), left, "")
 }
 
-// Truncate truncates a string to a given length, adding a tail to the
-// end if the string is longer than the given length.
-// This function is aware of ANSI escape codes and will not break them, and
-// accounts for wide-characters (such as East Asians and emojis).
+// Truncate truncates a string to a given length, adding a tail to the end if
+// the string is longer than the given length. This function is aware of ANSI
+// escape codes and will not break them, and accounts for wide-characters (such
+// as East-Asian characters and emojis).
 func Truncate(s string, length int, tail string) string {
 	if sw := StringWidth(s); sw <= length {
 		return s
@@ -44,6 +44,7 @@ func Truncate(s string, length int, tail string) string {
 	// Here we iterate over the bytes of the string and collect printable
 	// characters and runes. We also keep track of the width of the string
 	// in cells.
+	//
 	// Once we reach the given length, we start ignoring characters and only
 	// collect ANSI escape codes until we reach the end of string.
 	for i < len(b) {
@@ -120,7 +121,7 @@ func Truncate(s string, length int, tail string) string {
 // TruncateLeft truncates a string from the left side to a given length, adding
 // a prefix to the beginning if the string is longer than the given length.
 // This function is aware of ANSI escape codes and will not break them, and
-// accounts for wide-characters (such as East Asians and emojis).
+// accounts for wide-characters (such as East-Asian characters and emojis).
 func TruncateLeft(s string, length int, prefix string) string {
 	if length == 0 {
 		return ""

ansi/truncate_test.go

@@ -302,27 +302,49 @@ func TestTruncateLeft(t *testing.T) {
 }
 
 func TestCut(t *testing.T) {
-	t.Run("simple string", func(t *testing.T) {
-		got := Cut("This is a long string", 2, 6)
-		expect := "is i"
-		if got != expect {
-			t.Errorf("exptected %q, got %q", expect, got)
-		}
-	})
-
-	t.Run("with ansi", func(t *testing.T) {
-		got := Cut("I really \x1B[38;2;249;38;114mlove\x1B[0m Go!", 4, 25)
-		expect := "ally \x1b[38;2;249;38;114mlove\x1b[0m Go!"
-		if got != expect {
-			t.Errorf("exptected %q, got %q", expect, got)
-		}
-	})
-
-	t.Run("left is 0", func(t *testing.T) {
-		got := Cut("Foo \x1B[38;2;249;38;114mbar\x1B[0mbaz", 0, 5)
-		expect := "Foo \x1B[38;2;249;38;114mb\x1B[0m"
-		if got != expect {
-			t.Errorf("exptected %q, got %q", expect, got)
-		}
-	})
+	for i, c := range []struct {
+		desc   string
+		input  string
+		left   int
+		right  int
+		expect string
+	}{
+		{
+			"simple string",
+			"This is a long string", 2, 6,
+			"is i",
+		},
+		{
+			"with ansi",
+			"I really \x1B[38;2;249;38;114mlove\x1B[0m Go!", 4, 25,
+			"ally \x1b[38;2;249;38;114mlove\x1b[0m Go!",
+		},
+		{
+			"left is 0",
+			"Foo \x1B[38;2;249;38;114mbar\x1B[0mbaz", 0, 5,
+			"Foo \x1B[38;2;249;38;114mb\x1B[0m",
+		},
+		{
+			"right is 0",
+			"\x1b[7mHello\x1b[m", 3, 0,
+			"\x1b[7m\x1b[m",
+		},
+		{
+			"cut size is 0",
+			"\x1b[7mHello\x1b[m", 2, 2,
+			"\x1b[7m\x1b[m",
+		},
+		{
+			"maintains open ansi",
+			"\x1b[38;5;212;48;5;63mHello, Artichoke!\x1b[m", 7, 16,
+			"\x1b[38;5;212;48;5;63mArtichoke\x1b[m",
+		},
+	} {
+		t.Run(c.input, func(t *testing.T) {
+			got := Cut(c.input, c.left, c.right)
+			if got != c.expect {
+				t.Errorf("%s (%d):\nexpected: %q\ngot:      %q", c.desc, i+1, c.expect, got)
+			}
+		})
+	}
 }