Implement grapheme segmentation in Go

tools/wcswidth/char-props_test.go

@@ -0,0 +1,54 @@
+package wcswidth
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+	"os/exec"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+
+	"kitty/tools/utils"
+)
+
+var _ = fmt.Print
+
+type GraphemeBreakTest struct {
+	Data    []string `json:"data"`
+	Comment string   `json:"comment"`
+}
+
+func TestSplitIntoGraphemes(t *testing.T) {
+	var m = map[string][]string{
+		" \u0308 ": []string{" \u0308", " "},
+		"abc": []string{"a", "b", "c"},
+	}
+	for text, expected := range m {
+		if diff := cmp.Diff(expected, SplitIntoGraphemes(text)); diff != "" {
+			t.Fatalf("Failed to split %#v into graphemes: %s", text, diff)
+		}
+	}
+	cmd := exec.Command(utils.KittyExe(), "+runpy", `
+from kitty.constants import read_kitty_resource
+import sys
+sys.stdout.buffer.write(read_kitty_resource("GraphemeBreakTest.json", "kitty_tests"))
+sys.stdout.flush()
+`)
+	var output []byte
+	var err error
+	if output, err = cmd.Output(); err != nil {
+		t.Fatalf("Getting GraphemeBreakTest.json failed with error: %s", err)
+	}
+	tests := []GraphemeBreakTest{}
+	if err = json.Unmarshal(output, &tests); err != nil {
+		t.Fatalf("Failed to parse GraphemeBreakTest JSON with error: %s", err)
+	}
+	for i, x := range tests {
+		text := strings.Join(x.Data, "")
+		actual := SplitIntoGraphemes(text)
+		if diff := cmp.Diff(x.Data, actual); diff != "" {
+			t.Fatalf("Failed test #%d: split %#v into graphemes (%s): %s", i, text, x.Comment, diff)
+		}
+	}
+}