Add tests for decode_grapheme_clusters

tests/core/unicode/test_core_unicode.odin

@@ -0,0 +1,73 @@
+package test_core_unicode
+
+import "core:log"
+import "core:testing"
+import "core:unicode/utf8"
+
+Test_Case :: struct {
+	str: string,
+	expected_clusters: int,
+}
+
+run_test_cases :: proc(t: ^testing.T, test_cases: []Test_Case, loc := #caller_location) {
+	failed := 0
+	for c, i in test_cases {
+		log.debugf("(#% 4i) %q ...", i, c.str)
+		result, _ := utf8.grapheme_count(c.str)
+		if !testing.expectf(t, result == c.expected_clusters,
+			"(#% 4i) graphemes: %i != %i, %q %s", i, result, c.expected_clusters, c.str, c.str,
+			loc = loc)
+		{
+			failed += 1
+		}
+	}
+
+	log.logf(.Error if failed > 0 else .Info, "% 4i/% 4i test cases failed.", failed, len(test_cases), location = loc)
+}
+
+@test
+test_official_gcb_cases :: proc(t: ^testing.T) {
+	run_test_cases(t, official_grapheme_break_test_cases)
+}
+
+@test
+test_official_emoji_cases :: proc(t: ^testing.T) {
+	run_test_cases(t, official_emoji_test_cases)
+}
+
+@test
+test_grapheme_byte_index_segmentation :: proc(t: ^testing.T) {
+	SAMPLE_1 :: "\U0001F600"
+	SAMPLE_2 :: "\U0001F3F4\U000E0067\U000E0062\U000E0065\U000E006E\U000E0067\U000E007F"
+	SAMPLE_3 :: "\U0001F468\U0001F3FB\u200D\U0001F9B0"
+
+	str := SAMPLE_1 + SAMPLE_2 + SAMPLE_3 + SAMPLE_2 + SAMPLE_1
+
+	graphemes, _, _ := utf8.decode_grapheme_clusters(str)
+	defer delete(graphemes)
+
+	defer if testing.failed(t) {
+		log.infof("%#v\n%q\n%v", graphemes, str, transmute([]u8)str)
+	}
+	if !testing.expect_value(t, len(graphemes), 5) {
+		return
+	}
+
+	testing.expect_value(t, graphemes[0].rune_index, 0)
+	testing.expect_value(t, graphemes[1].rune_index, 1)
+	testing.expect_value(t, graphemes[2].rune_index, 8)
+	testing.expect_value(t, graphemes[3].rune_index, 12)
+	testing.expect_value(t, graphemes[4].rune_index, 19)
+
+	grapheme_1 := str[graphemes[0].byte_index:graphemes[1].byte_index]
+	grapheme_2 := str[graphemes[1].byte_index:graphemes[2].byte_index]
+	grapheme_3 := str[graphemes[2].byte_index:graphemes[3].byte_index]
+	grapheme_4 := str[graphemes[3].byte_index:graphemes[4].byte_index]
+	grapheme_5 := str[graphemes[4].byte_index:]
+
+	testing.expectf(t, grapheme_1 == SAMPLE_1, "expected %q, got %q", SAMPLE_1, grapheme_1)
+	testing.expectf(t, grapheme_2 == SAMPLE_2, "expected %q, got %q", SAMPLE_2, grapheme_2)
+	testing.expectf(t, grapheme_3 == SAMPLE_3, "expected %q, got %q", SAMPLE_3, grapheme_3)
+	testing.expectf(t, grapheme_4 == SAMPLE_2, "expected %q, got %q", SAMPLE_2, grapheme_2)
+	testing.expectf(t, grapheme_5 == SAMPLE_1, "expected %q, got %q", SAMPLE_1, grapheme_1)
+}